text:
Does reality exist?
Does reality exist? Carlo Rovelli (a famous theoretical physicist) doesn't think so and he cites Nagarjuna as believing the same:

Rovelli has a different idea. He says reality doesn’t exist. The
reason physicists have been led astray by bonkers theories in the 100
years since Helgoland is because they can’t bear the thought of not
being real.
It was at this point — a third of the way through the book — that I
mimicked Heisenberg and took my first long, befuddled walk. Reality
doesn’t exist? What on earth does that mean? Rovelli’s favourite
example is a red chair. ‘Red’ doesn’t exist, for sure — everyone knows
that philosophical chestnut: it’s just the way our brains make sense
of light of a certain wavelength. But Rovelli also insists that
nothing else about the chair exists either — its weight, its shape —
except in its relationship to the person looking at it. And you can
keep banging away at this type of argument until you get to the level
of the atoms forming the chair. Insisting that anything about this red
chair needs to exist outside of relationships is metaphysical
neediness.
Part of the fun of Rovelli’s book is that your immediate reaction to
his ideas — repugnance or delight — isn’t meaningless. Without
mathematics or experiment, by page 81 your thoughts are at the
frontier of quantum theory, and it’s time for your second
brain-cudgeling walk. If things exist only by virtue of their
interaction with other things, what happens to them between times? Do
they vanish? Do instants of time also not exist? Does it even make
sense to talk this way? Oh dear, oh dear.
Rovelli devotes a precious chapter to the work of the second-century
Buddhist philosopher Nagarjuna, who also insists there is no ultimate
layer of real things.

Emphasis mine. These ideas form the heart of his well regarded Relational Interpretation of Quantum Mechanics and are discussed extensively in his new book Helgoland.
Other questions on this forum have asked whether physical reality exists, but the highest rated answers have mostly danced around the question. They argue that it is our "attitude" about such questions that is relevant... In other places, the assertion is that this question is one of the "thickets" or is somehow unanswerable or is somehow not amenable to logic.
I find all of these quite flaccid in the face of this prominent theoretical physicist coming out quite explicitly saying that our current best known laws of the universe (properly interpreted) indicate that reality itself doesn't exist and that the unwillingness to acknowledge this by other physicists is "metaphysical neediness!" He is arguing that we can talk about this meaningfully and use our reason to arrive at this conclusion with mathematics, logic and empiricism.
I'd also say that it is quite obvious the answer to this question has vast soteriological consequences that are very deeply relevant to Buddhism and should not just be ignored or danced around. So, is he right?

Related: What buddhism says about physical reality?, Is lack of inherent existence the same as 'not real'?

With all due respect to the scientist, according to me, his understanding of Madhyamika or of the Red colour is wrong. He jumps into saying Red is unreal. That is not a given. Just because its an interpretation of the mind that doesn't mean there is no Red colour outside our minds. Just like the shape and weight of the chair. Regarding Nagarjunacharya saying the world is unreal. Afaik he doesnt say that. He only says nothing can be said about the World. It can never be said to exist or not exist. That is th idea.

@VARUN.NRAO: Indeed: ""To think ‘it is,’ is eternalism,
To think ‘it is not,’ is nihilism:
Being and non-being,
The wise cling not to either."
-Mūlamadhyamakakārikā 15:10

You might like this talk about creating a visible quantum object https://youtu.be/dvYYYlgVAao It points at how 'weird' quantum behaviour seems to be about how isolated a system is, and our visible world is not normally 'fuzzy' in a quantum way because there are interactions all the time, normally. We think 'here' is real, and also 'there' is real. This shift says, what if instead, only interactions are real? That is I think compatible with quantum mechanics, and Nagarjuna.

He says reality doesn’t exist
Does he, or is that a paraphrase by the reviewer? And if he does, is he simplifying for the reader? Or trolling a bit, maybe trying to challenge the reader by saying something edgy?
The reason physicists have been led astray by bonkers theories in the 100 years since Helgoland is because they can’t bear the thought of not being real.
That sounds like not even hearsay -- merely imputing motive -- but who knows.
But Rovelli also insists that nothing else about the chair exists either — its weight, its shape — except in its relationship to the person looking at it.
I'd phrase that more impersonally -- not "in relationship to the person" but "in relationship to the observation" or "in relationship to the experiment".
I suppose it's axiomatic to physicists -- it was when I was at school, a while ago admittedly -- that you "observe" things "experimentally" and that the observation interacts (or interferes) with what's observed.
So for example when you look at a couch you're observing the effect of shining photos at it.
There are other ways to observe a couch, other experiments -- with your bum (by sitting on it), or perhaps with a pair of scissors -- or with a jar of acid, or a stick of dynamite -- or by asking someone else what they think of it.
Different experiments lead to different observations.
If things exist only by virtue of their interaction with other things ...
(As I was saying)
... what happens to them between times?
Yeah. I guess that's where sunyata becomes relevant, i.e. the question supposes that "they" (things) have or possibly even haven't some thingness (i.e. existence).
It might be a meaningless question -- like if I said, "white is the only colour", then it wouldn't make sense to ask, "What colour is it when it isn't white?"
reality itself doesn't exist
That may be an exaggeration or subject to misinterpretation. There's a Zen story (titled Nothing Exists) that may be relevant. And scientists make a fuss about consensus and reproduceable experiments -- they're presumably studying something, whether that (subject/object of study) is called "reality" or merely "interactions" might be just semantics, right?
Still it's something Physicists have talked about (including Shrodinger's Cat for example), as Philosophers may have too.
I haven't read the book -- the review or paraphrase of it you quoted makes it sound like popular science possibly written so as to "Épater la bourgeoisie" -- especially the supposed shock value of its coming from a physicist.
the answer to this question has vast soteriological consequences that are very deeply relevant to Buddhism
Perhaps so, but perhaps also it's something you learn when you're a child -- that your experience of the world and people depends on and may vary according to your interactions with them -- a truism then.
This also reminds me  of Le Guin's Bryn Mawr Commencement Address -- that it might sound remarkable to hear this message spoken in what she calls "the father tongue" -- where in another context it might be just a truism (or worse).
Now I don't mean to say that Buddhist doctrine is written in the father tongue or mother tongue. I think that what makes Buddhism different than Physics, I found to be a welcome difference:

Rational and humane
Offering salvation (e.g. from death)
Using metrics like "virtue" and "wisdom" and "truthful" and "harmless" and so on as a measure -- measures which aren't in the same realm or domain as physics.

So, is he right?
I might have been harsher about physics, and a book that I haven't even read, than they deserve -- sorry if that's raining on your enthusiasm.
To answer your question, though, the review doesn't entice me to buy the book -- so I don't know if he's right -- the author (if not the reviewer) is presumably more right about Physics than I'm likely to be.
But the way the review presented it, the doctrine does sound to me unremarkable, well-known, easily explained in terms of orthodox philosophy of science -- so to answer your question, "Yes he's right".
The only surprising thing to me is the claim that (other) "physicists have been led astray", because the little that's paraphrased here seemed to me mostly orthodox (so wouldn't they see it that way too). Though even the bit about physicists being astray might be 'right' (I've for sure met fewer of them in life than he has), for example I don't know that the Schrodinger's Cat discussions were ever much good.

"And if he does, is he simplifying for the reader? Or trolling a bit, maybe trying to challenge the reader by saying something edgy?" No, I don't think he does. Why do you think the stmt is edgy? Is it uncomfortable to think this is true?

I think it might be understood (or misunderstood) as solipsism (e.g. here), or nihilism. It might imply there's something else (but without saying what), other than reality, which does exist. And if it's true it might be true in a narrow context -- like from the etymology of "reality" I get the Latin word res and from that a Physicist's view of "thing" -- but that's perhaps not the common-sense meaning. Even the reviewer claimed that the statement was befuddling.

By the way I'm told we learn object permanence as infants. Is that perhaps related to secure attachment -- like, "does mommy continue to exist, when she's gone?!" :-( --and  possibly "uncomfortable" for other people for that kind of reason? Or for me it might be uncomfortable because it's a grind to think about Physics, or to try to make sense of other people talking about it when they weren't taught it as I was taught it (sometimes leading to impasse like "quantum woo" and "not even wrong").

Hi ChrisW, see my answer and let me know what you think of it. It is very easy to understand the fact that reality does not exist is not synonymous with nihilism, naive solipsism, or the absurd idea that nothing exists. You just have to point out that 'real' is not synonymous with 'exists' and this can be seen pretty easily if you think about it for a few seconds.

@YesheTenley Perhaps you talk as if words (like 'real' and 'exist') have inherent and objective (or universal, constant) meaning. If you make a statement (e.g. "'real' is not synonymous with 'exists'") then I can re-evaluate what you've said and re-assess what you might be saying or referring to (and so understand it). The words are closely related though -- I think that you've implied previously that (in your vocabulary) "real" is the same as "truly exists" -- where in another context, e.g. arbitrary/casual speech from a lay-person, I might have assumed that "really" and "truly" are synonyms.

In the case of what was alleged to be Rovelli's statement ("reality does not exist") I assume that the context might be physics and that the argument for that -- which I believe is "right" -- is more-or-less as stated in Epic's answer i.e. that "The space-element does not at all exist prior to its defining characteristic": where "defining characteristic" might be a synonym for "description of an experimental observation".

I suppose physicists readily admit that words and descriptions, models, are artificial. They may assume there's a so-called reality which precedes the description, on which the description is based or grounded. I'd be inclined to say that whatever might be described or viewed (I think of the word "view" as it's used in the first sentence of this answer) as reality might be a concept not a simple object.

This is an excellent excellent point @ChrisW!! Words only exist as mere convention. So the question I guess is what is the most useful agreed upon convention for our purposes? I have some proposals that I think are good workable definitions, but if someone else has others that work better I’d be happy to know them. That is why I asked that other question :)

The reality is real in every right perspective, but it is exist only when it arising only. The reality arises and vanish immediately more than trillions time (10¹²) in a second. It isn't exist before and after that, but it is real, if the thinker can think of it by the right perspective, causes and effects.
Similitude: you are not sleeping now because you are reading this answer, but you know you has slept because you are not sleepy  now, you have a bed, you can recall your sleeping time, your partner tell you that you has slept already, etc., (causes and effects). Sleeping you are not exist, but you are recall to the fact whether you has slept.
Above is  only similitude. That similitude is the imaginative fact in Buddhism. The reality is too small, too fast, and too simple than that trillions time (10¹²) in a second. Learn Abhidhamma and Patthana for the explanation. And Abhidhamma study is not enough. You need to meditate the concentration meditation and insight meditation to see the reality yourself. I recommend Pa-Auk Sayadaw for the beginning. He is the Tipitaka memorizer with long time experience in meditation.

Quoted below is Candrakīrti's Lucid Words - A Commentary on Nāgārjuna’s Wisdom.
Perhaps Mr. Rovelli is misrepresenting Nāgārjuna’s teaching.
True dharma is the middle way. Those who see existence or non-existence don't see peace.

5  Analysis of the Elements (dhātus)
5.1. The space-element does not at all exist prior to its defining characteristic; if it were prior to its defining characteristic, it
would have no defining characteristic.
5.2. There is no existent (bhāva) anywhere without a defining characteristic. If there is  nothing without a defining
characteristic, then to what does a defining characteristic apply?
5.3. A defining characteristic does not apply to what has no defining characteristic, nor does it apply to what already has a defining
characteristic.  Nor  does  it  apply  to  something other than what
has or does not have a defining characteristic.
5.4. If a defining characteristic is not applying or present, then it does not make sense to speak of the characterized. If the
characterized does not make sense, then the defining  characteristic
is not possible.
5.5. Therefore, the characterized does not exist, and the defining characteristic does not exist.  And an existent  (bhāva)  does not
exist without what is characterized and the defining characteristic.
5.6. If there is no existent (bhāva), then of what would there be nonexistence (abhāva)?  And [if] the analyzer that has neither the
quality of existing nor not existing, how does he know either the
existent or the nonexistent?
5.7 .  Therefore,  space is neither an existent nor a nonexistent;  it is neither the characterized nor the defining characteristic. And the
other five elements are the same in this regard as space.
5.8. The dim-witted who see existence (astitva) and nonexistence (nāstitva) of things do  not see peace, which is the quieting
(upaśama) of what is to be seen.

Rovelli never said there was no existence. Maybe it is you that is misinterpreting his words. To say that reality does not exist is not to say that nothing whatsoever exists.

Your question reads.... Does reality exist? Carlo Rovelli (a famous theoretical physicist) doesn't think so and he cites Nagarjuna as believing the same... Without paraphrasing .. you said.." ROVELLI CITING NAGARJUNA SAID REALITY DONEN"T EXIST ". But according to Candrakīrti' Nāgārjuna’s did not say that reality doesn't exist!.

What do you mean by "To say that reality does not exist is not to say that nothing whatsoever exists"... That statement is completely off and illogical... Are you claiming the existence of unreality?

Your quote above of chandrakirti does not mention reality or real. It is not dispositive. Further, I can quote many many sutras which 2nd turning sutras which say that reality doesn't exist. The only real thing is emptiness. Tsongkhapa literally says this in his Ocean of Reasoning.

It is not off and not illogical. Why do you think it is? Is the existence of some thing dependent upon it being real? Are non real things non existent? Are 'real' and 'existent' synonyms for you? Do illusions not exist? Do dreams not exist? How do you define reality and or 'real' and why does it cause such discomfort to think that reality doesn't exist? Maybe read my answer above and see what you think of it.

I have read your answer, and I I think you are stoping short taking comfort in non-existence. You are stoping @ 5.5 in Candrakīrti's line of argument above " non-existence of bhāva ".  Go on direct emptiness to the analyzer and you will see why true freedom is beyond both existence and non-existence

Are 'real' and 'existent' synonyms for you? If not, how do you define real? I have a clear definition in mind and I'll share it with you if you like, but first I'd like to know what you are using as a definition in the answer and comments above :)

I think you have made it clear in your dream analogy what you mean by real and nonexistence. You are leaving the ' I ' the ego that awakes as a determining factor to define what is real and what is not real. What Candrakīrti's is saying is go on attack the ego with emptiness and then you will not have the reference even to say Real.. unreal.. existence nonexistence.

So to answer your question directly .. Are 'real' and 'existent' synonyms for you? NO BOTH ARE EMPTY WORDS.

That isn't a complete answer. Sure they are words. And they lack inherent existence like all things. But what are you using for your definition of these words since you acknowledge they are not synonyms? Also, see the edit to my answer where you can see video of a renowned Tibetan master giving essentially the same answer. Maybe that will help.

"Does reality exist?"
Ultimately no, it doesn't.

This question and the answers it has provoked have predictably stirred some uncomfortable feelings and thoughts. If one looks really hard at why this question makes people squirm (even Buddhists trained in the dhamma and the dharma who've literally been reading sutta after sutra giving myriad specific testimonies to this question in different contexts for different audiences), then one might get a glimpse of that which is to be overcome. Why are we so attached to the idea that reality exists? Why does it make us so uncomfortable to just categorically say it is not so? Why do we feel the need to dance around the subject and fein nuance and subtlety?
I propose two reasons:

Legitimate concern that being bold and telling the truth about emptiness and reality will cause others to misunderstand and drive off the cliff of nihilism or absurd naive solipsism

The "metaphorical neediness" spoken of above which is the ego feeling challenged for its very survival. How can it possibly be that reality doesn't exist? How can it possibly be that I am not real? That I am like an illusion or a drop of dew or a bubble? That I am like a magical trick with utterly no real existence? How can my sister, my brother, my mother, that object that I crave so badly... how can you say that isn't real?? Saying that "reality isn't real" bubbles up something deep and disturbing almost like reality at its core could be broken. That the walls and illusion of the world are tenuous and could crumble at any nanosecond. The ego fears this above all and conjures up whatever defenses it can marshall. "Reality isn't real? Are you crazy??!! That's akin to saying nothing exists! That my life doesn't matter! That no ones life matters!"

Often times I think the two reasons above are conflated and #2 likes to piggy back on #1. The fact that reality does not exist has been categorically stated many, many, many, times in many suttas and sutras. When this caused people to shriek in fear as they simply weren't ready to hear or understand the Buddha and those Dharma teachers who followed couched it in various ways to soothe.
To understand why this is so soteriologically important to the aim of Buddhism one has to fully grapple with that aim. For those who believe that Buddhism is merely a kind of empirical self-help therapy system that leads to moderate decreases in suffering, then they have not really bought into the aim of the Dharma. They are again feining to grapple with the soteriological aim of the Dharma, but they don't really believe it. If you believe the Buddha's intent was to provide a mild balm to treat the symptoms of samsara and not a transcendent liberation and awakening, then of course this question and its answer will cause squirmishness. On the other hand, if you think deeply and consider that maybe the Buddha was not exaggerating and really did have transcendent liberation and awakening in mind... then this question and its answer can be seen as precisely at the heart of the soteriological aim of the Buddha.
If one truly wakes up to the answer to this question... not in a feining way, but in a truly transcendent awakening, then the way in which the truth to the answer to this question can overcome ignorance and deliver freedom is like this:
You are having the worst nightmare of your life. You are are being slaughtered slowly. Eaten alive. Burnt and tortured. Boiled in oil. Everyone is mocking you as this happens. It is endless. The pain and suffering is pure agony. And then you wake up.
Do you remember the feeling of freedom and relief waking from such a dream? From finding out that it was just a nightmare? That it was utterly not real? This is why this question and its answer is soteriologically important. It is precisely in this way that transcendent awakening to the reality that reality does not exist brings freedom. This is the way that truth overcomes ignorance. This is the deliverance.

Chögyal Namkhai Norbu
"Sometimes we have very nice dream. Fantastic dream... And we enjoy. We are very happy. We are dreaming, for example... ...I'm looking and someone is selling... lottery ticket. Very, very big lottery. I am taking and buying from someone and I am returning home. And I am seeing the television. And when I am looking at my number... The television is saying that number! Then I feel very happy. "Oh, what do I do now?" All this money. I am really happy and then I wake up. When I wake up, I discovered that is a dream, unfortunately. I am not happy. Or sometimes... very, very bad dream. There are many people that want to kill me. They are arriving in my house. Then they are starting to kill me. I feel very afraid. That moment I wake up. And I discover, "Oh, that is only a dream!" I am very happy. You see, good or bad. Even good or bad. A dream is a dream. Unreal. So Buddha is saying, our life is just like a dream. Big dream. Dream of night is a very small dream, but... Our life's dream, it has many day and night, day and night etcetera. When we discover that... Dreams, we discover when we wake up. But big dreams, we discover... When we are dying and being in a state of Bardo (transitional state)."
Emphasis mine.

For those who aren't familiar that the above is taught in the Gelug tradition of Tibetan Buddhism see this for a handy western reference.

The proponents of the Madhyamika Svatantrika, the second highest
Buddhist philosophical tenet system, assert that conventional truths
can be divided into real and unreal conventional truths. However,
according to the Madhyamika Prasangika tenet, such a division is not
correct because all conventional truths are deceptive or false and
therefore not real. In order to be real, a phenomenon must exist as it
appears. Conventional truths are deceptive because to sentient beings’
direct perceivers they always appear to exist inherently, as if
findable among their bases of imputation. Hence, conventional truths
are unreal whereas ultimate truths are real. Ultimate truths are real
or non-deceptive because to sentient beings’ direct perceivers they
never appear to exist inherently but appear the way they exist, that
is, they appear to be empty of existing inherently. 18 However, the
proponents of the Prasangika tenet assert that relative to the
perspective of the world objects which are not ultimate truths can be
categorized into those that are real and those that are unreal.

The language used above includes the def. of real as taught in Gelug monasteries. When we speak of something being real - for someone who has a modicum of understanding of this - we take into account the perspective we are speaking from. We look at real with perspective to the world and real with perspective to the ultimate. In the latter, nothing, save emptiness, is real and not deceptive in its appearance.

And it is not just Gelug. Here is a prominent and very respected teacher of the Rime movement saying much the same:

The last two lines of sloka 38 are the conclusion. None of these
phenomena exist truly within the relative truth or the ultimate truth;
therefore, they are neither eternalist nor nihilist. On the ultimate
level, everything is like when you dream that a child is born to you,
and then within the same dream the child dies. From the ultimate point
of view, since there was no real birth of a child, the death of that
child is also not real. And in the relative truth, everything is
dependent arising, thus neither eternalist nor nihilist.

Emphasis mine.

And here is Chandrakirti himself saying something similar:

In ordinary experience, just as while awake,  While sleeping, these
[above] three seem to exist;  Once awake they do not.  Awakening from
the sleep of ignorance is similar.

This is how ignorance is destroyed. By waking from the dream of reality.

Ouch! It was your first line that through me a punch! Try not to adopt that first line as a belief system. It may cause untold issues later in your practice.

The first line? You mean, "Ultimately no, it doesn't."? What fault do you see that I should be careful of?

We can examine nothingness, like one would examine the space in a room, but to ascribe a premature meaning to the absence of what you cannot perceive is to give impetus to samsaric turmoil. I'm just saying, try not to adopt this as a belief. It's hardly middle ground. It's better to work from the premise that there are things, and that there aren't things. That way, the neurotic mind cannot grasp onto anything. When it cannot grasp onto anything, it takes flight like the analogy of the land-finding crow in the Visuddhimagga - by no effort from you, it looks for nibbana.

@NeuroMax Thank you. The first line in the answer is from a svatantrika prasangika viewpoint I believe. That is, it asserts a view which is what I think?? you are warning against here?

Yesha Tenely - you're welcome. I think you'll have to go with what you understand from your path. You would be the best judge of that. ;-)

With only reading the question, the Pali suttas say a fixed reality exists regardless of perception of it. Refer to AN 3.136.

I found this answer remarkable -- I hadn't considered the "three characteristics" as the topic of this question, i.e. what the physicist meant when referring to "reality". And it might seem tempting to see those characteristics (or Ven. Sujato translates, "law of nature" and "natural principle" -- dhammaṭṭhitatā and dhammaniyāmatā) as being more existent than any "thing" (or "substance"). There is also for example the "Law of Gravity" (which Persig fwiw implied might predate people's descriptions of it). Or the sutta may say "persists", not "exists" -- ṭhitāva, from tiṭṭhati ("stand").

all my answers are remarkable.

This answer is truly remarkable in that it is the only one that called out a subtle problem with the OP. Bravo! I think the Buddha did in fact say that there is a reality. That there is at least one thing (here 3 things) that are in fact real.

@ChrisW So, the fixed reality is the three characteristics?

In Mahayana, it is said that only the perception of emptiness is undeceptive in its appearance and is hence 'real'. Marking this answer as answering the OP. Really good job. But ChrisW, again, the fact that these 3 things are real does not mean that they are the only existents because 'real' is not synonymous with 'exists'.

@ruben2020 I think that the three characteristics are observations or descriptions (of "all sankharas" and of "all dhammas"); and they're "true" in that they're observed to be descriptive, predictive, and useful -- even enduringly and universally true. Like other models they're concepts, and descriptions of interactions, or according to a given measure; and are not "the fixed reality" itself in the physical sense of that word -- e.g. they are not a substance! Even what they're characterizing seems to me experiential not just physical (and so Buddhism addresses problems which physics doesn't).

no no no no no -  the three characteristics are NOT observations or descriptions. AN 3.136 say the complete opposite of this. please remove the poison wrong view from your stomach forever. please give up these non-Buddhist ideas found on solipsist papanca forums such as DW. thank you

Shit answer because the part "regardless of the perception of it" is conjucture of OP and isn't in the text referenced. It is a typical doctoring of the sutta expression that i tend to accuse the op of frequently engaging in, inferring what is not to be inferred. As a matter of fact the expression is disagreable if taken to suggest that the three characteristics apply to something which repudiates or are in & by themselves repudiating the six senses of perception established in sabba sutta.

If op means 'regardless of the perception of it' as in whether you think gravity exists or is real or not, regardless of this perception if yours, the gravity will come into play and you will hurt yourself if you jump from a cliff' then this is agreeable meaning but this a very different statement lol.

@Buddhism I'm guessing he meant, "regardless of whether a Realised One arises (to perceive it)", no?, implying that the characteristic precedes the Realised One's observation of it. However I read it as that the sutta is addressing bhikkhus, and others, and I take it that the sutta is addressing or describing what they perceive (and that in that sense it's not "regardless of perception").

The two alternative interpretations to what was said in brief 'something exists repudiating perception' are stunningly different. To say that 'something exists repudiating perception, repudiating the allness of the all as spoken of in sabba sutta' and to say that 'things are as they are no matter what you think of them' these are very different things and

@ChrisW the simple interpretation of the sutta is akin to saying that there are discoveries to be made whether one discovers them or not. Has nothing to do with whether objects exist independently of the six classes of perception. We know it has nothing to do with that because it is stated in the Sabbe Sutta that there is nothing repudiating nose&smell, eye&form, tongue & taste, ear& sounds, body & sensations, intellect & ideas.

So basically the only way OPs answer is fit to be posted on this site is if he means that "things are as they are whether you know of & understand them or not". Somehow i doubt that this is what he meant and it should be removed either way because it is off-topic, if it's not off topic then i apologize having misunderstood the question. In summary this answer is either contradictory to sutta or is irrelevant to the question.

The meaning of the sutta is analogue to saying e=mc2 whether this is known to people or not, whether an Einstein arises in the world or not. This is the simple interpretation and any more complex interpretation needs to meet the burden of proof. We know e=mc2 was true before it was discovered and we know all things had 3 characteristics before the Buddha discovered that. This is quite simple.

@Buddhism We know e=mc2 was true before it was discovered Well that's what I'm not sure of and which may be an example of the "physicists have been led astray by bonkers theories" from the OP. "e=mc2" is a simple mathematical model which describes and predicts observations. Being a model I think it's like a simple two-dimensional picture of three-dimensional reality -- and can't argue that a picture exists before the painter! Also it's a model of observed physical behaviour or interactions -- but it becomes a solution looking for a problem!

Great minds think alike tho. We know there were other Buddha's who re-discover lost knowledge and formulate a descriptive model of elements, conditional relations and characteristics essentially in the same way. The model to be formulated doesn't change and the nature of phenomena that comes into play for this or that person is persistently constant whether someone understands it or not.

It is like if two painters were to paint what they saw after coming to see the same thing, it wouldn't be one and the same picture but the content would be essentially the same.

@YesheTenley regarding your earlier answer to one of my questions "I would challenge you to find even one set "thing" in this world or any other in which all beings immediately agree or have a universal objective experience that does not differ in any significant way." Since you don't believe any 2 people can have a same objective experience, then how can you believe or make sure there exists any reality which by definition is always same eternally?

I don’t @Double Knot

Do u mean "u accept a fixed reality exits while in the mean time no 2 people can agree a universal objective experience that does not differ in any significant way"? If so, then it seems whether there exists such independent reality or not has no utility or meaning at all, since anyway no 2 people will agree exactly and will experience it differently in some significant way... Any suggestion to shed some light for me on this reality-irrelevance issue?

No, I'm saying "I don't" as an answer to your, "how can you believe or make sure there exists any reality" ... that is, I don't believe there exists any reality other than emptiness.

People might discuss what exists based on the agreement that something exists.
Then Decarte said "i think therefore i am". This is an ambiguous statement because the existence of thinking does not necessarily mean that the object of thought is as real as the thinking itself and repudiates thinking. It can be said that the ideation of 'i am' there is included in the reality of thinking, it is a thusness and a variety of thinking.
Take this statement 'I think about spiderman, therefore spiderman is real'. Well it is and it isn't, it isn't real as the thinking is real because it does not repudiate thinking but it is real as it is that what i think about.
What would be repudiative to thinking? Well in example it can be agreed that seeing is real and it repudiates thinking. It is something that is as real as thinking is real and is real in the same context. There can be seeing without thinking and they are both real in the same sense.
If i said that spiderman is as real as superman, this would be similar. They are both real and repudiate eachother in that imaginary world of superheroes, in that context we can delineate a distinction and separate them. There can be spiderman without superman.
We can delineate a distiction between thinking and that which we think about but we can not separate the object of thought from thinking, there can be no thinking about superman without thinking. What is meant is that we can only separate that which thinks from the object of thought by changing the object of thought, think about something else but an object of thought is something included in thinking itself.
We differentiate between that which thinks and the object of thinking when analyzing the constituents of the reality of 'thinking'.
There can be hearing without discursive thought, likewise smell, taste, seeing & sensations, these are affirmed to exist in the same context and are repudiative of eachother.
The Buddhas say that nothing repudiates the allness of nose & aromas, the eye & the forms, the ear & sounds, the tongue & tastes, the body & bodily sensations, the intellect & ideas.
They don't say that the eye isn't real, the eye is something among everything.
The ideation of spiderman is also something among everything and spiderman is something among everything. Spiderman is something i think about and it is something particular in the imaginary world of superheroes. Doesn't mean that i should go looking for a spiderman in the backyard and if i was to go looking then i would've been doing so due to grasping with wrong view.
Being classed as something among everything doesn't make something as real as everything else, it only makes it as real as that which it repudiates.
It is said that everything is thought of as conditioned element and the thought of the conditioned is repudiated by the thought of an unmade element. This unmade element is not a class of somethings unlike that which is spoken of as everything and the unmade isn't a something among everything even tho the thinking & speaking of it is something among everything.
It is not an everything for it is a single element, not a class of elements unlike ie the element of 'thinking' is a class of that which thinks and that which is thought about or how everything is a class of somethings.
Not being a class[ification] of somethings, it isn't a class or an aggregate of somethings, nor is it being classed as something among everything, it therefore does not contradict the Sabbe Sutta wherein it is said:

The Blessed One said, "What is the All? Simply the eye & forms, ear & sounds, nose & aromas, tongue & flavors, body & tactile sensations, intellect & ideas. This, monks, is called the All. [1]  Anyone who would say, 'Repudiating this All, I will describe another,' if questioned on what exactly might be the grounds for his statement, would be unable to explain, and furthermore, would be put to grief. Why? Because it lies beyond range."

It doesn't contradict it because it is not another everything nor a something among everything by definition but it is that which isn't included in the allness of the all.

"'Having directly known the all as the all,[8] and having directly known the extent of what has not been experienced through the allness of the all, I wasn't the all, I wasn't in the all, I wasn't coming forth from the all, I wasn't "The all is mine." I didn't affirm the all.

One should note that intellect in the sabbe sutta can be substituted for mind or consciousness

what's called 'mind,' 'intellect,' or 'consciousness,' the uninstructed run-of-the-mill person is unable to grow disenchanted with it, unable to grow dispassionate toward it, unable to gain release from it.

Then it can by inference be spoken of as is that which knows & cognizes the ideas and also as that which cognizes the forms visible by the eye and knows eye as the eye.
Therefore one can see that

When an object enters ‘the door of the eye’ or any of the other 5 senses, it enters also the door of ideation; ‘the door of the eye’ is included as a delineation of the spheres of the mind-base, included in what is called ‘mind-base’; it is mind-made. (for reference; M. i. 295 (see Caroline A.F,  Rhys Davis, first translation of Dhammasanghani Psychological ethics))

Unfortunately i can't find a better reference explaining this and didn't take note of where i found the above excerpt but i am 100% sure this in the theravadin texts and that there are better & more authoritative sources, i just didn't take note and didn't save what i've come across when studying abhidhamma and their comy.
Furthermore

"Feeling, perception, & consciousness are conjoined, friend, not disjoined. It is not possible, having separated them one from another, to delineate the difference among them. For what one feels, that one perceives. What one perceives, that one cognizes. Therefore these qualities are conjoined, not disjoined, and it is not possible, having separated them one from another, to delineate the difference among them."

So this is how one infers the 6 classes of ideation, feeling & perception.
Furthermore what exists that has come into being, what has come into being is made and made is another word for sankhara or creation and it is therefore also conjoined with perception, feeling & consciousness.
That leaves only the class or aggregate of form which is basically a subset of ideation thusness pertaining to the 5 faculties of seeing, hearing, smelling, tasting & sensing with the body.
This subset of ideation describes the thusness of ideation and does not repudiate ideation, it isn't discursive thought or a mental act of adding two numbers together; but it is a mental act of conception & perception of particular elements namely the eye & visible forms, nose & aromas, ear & sounds, tongue & flavors, body & bodily sensations, these color the ideation as that based on the five faculties by which one experiences agreeable & disagreeable things.
This is how one infers the 5 aggregates where 4 aggregates are conjoined from the sutta and how there can be arupa jhana.

The reason physicists have been led astray by bonkers theories in the 100 years since Helgoland is because they can’t bear the thought of not being real.

This is cute because it can and probably should be interpreted as an inability to accept the truth due to being yoked to the doctrine of self which is at odds with the Buddha's dharma.
This ideation about elements external & internal to the nervous system existing only in the context of perception is quite old.
In the beginning of 1900's physicists cleared up their language and many still struggle to accept the implications of special relativity and quantum experiments.
People struggle a lot trying to imagine what an object is like when not observed and they try to make it into something familiar like 'a wave' but it's most definitely not a wave, or they model an atom as a 'cloud' of electrons around nucleus and they go on to imagine that it is like that when it is most certainly nothing like a cloud.
When something is thought of as being in a superposition, they think they are talking about a not-perceived object's location rather than realizing that the wave function is a predictive model of a to be objectified state of perception.
What the wave function predicts is only the possible outcome of measurement or observation.
The way these things are thought about is quite backwards in many ways. Eg the waves of the ocean appear that way because of underlying QM rather than an electron behaving like like a wave. Therefore asking why does an electron behave like a wave is misleading because it doesn't behave like a wave, rather the waves of the ocean appear as they do due to QM.
How is this related to Buddhism? It's about namarupa being supported by consciousness and consciousness being supported by namarupa, about the allness of the all and objectification of non-objectification.
Is also about adherence to the doctrine of self or in general ditthiyogo and avijjayogo that plagues people.

@Buddhism can you answer the question though? Does reality exist? :)

I don't think it should answered categorically and that is why the statement was followed by a book explaining what the person means by existence. I can say it's about as real & existent as a dream or a mirage.

I'd be interested to hear why you think it can't be answered categorically, but I'll let this question soak for a bit before I open that question. Thanks!

You know these famous quotes? "Reality is merely an illusion, albeit a persistent one" and "One who looks upon the world as a bubble and a mirage, him the King of Death sees not". I think these are on point.

I don't think answering categorically is a good idea because if one talks about this in the context of the doctrine of self then a denial of the existence of things leads to view that all things are mere projection of an underlying eternal element which projects, it is close to eternalism. If one says that things exist, then one says that self exists and if self exists then one is close to view of annihilation of an existent being for death.

@ruben2020 thank you for picking up slack and bothering to edit. I generally don't like mixing physics and dhamma expression exactly because it requires a lot of cross referencing. Therefore these answers are just aimed at people who are already trained in that terminology and is of a lower value to the community but a lot of traffic on BSE is from the Physics site and therefore i will keep doing it because some people might understand.

@ruben2020 If i thought cross referencing a few Sutta would help then i would do it but i really don't think it would help either type of reader. Therefore i thought it to be more trouble than it's worth.

@ruben2020 Why did you (or another mod) remove the commentary explaining why i didn't give a categorical answer? Could've maybe added it to the answer... Outright deleting perfectly good commentary is not ok.

It's not clear how your last paragraph relates to the main body of your answer or the question being asked.

It is not clear because it wasn't in the answer and isn't supposed to be in the answer. The mod pestered me about substantiation and i added a comment to make it so that they don't delete the answer, the comment which a mod then embeded in the answer even tho i specifically explained that i don't like mixing terminology of physics and the dhamma and why.

I'll try to answer based on the Pali Canon and then connect it back to Madhyamaka.
Using MN 1 below, the Buddha describes how an untaught ordinary person sees reality.
From MN 1:

“Here, bhikkhus, an untaught ordinary person, who has no regard for
noble ones and is unskilled and undisciplined in their Dhamma, who has
no regard for true men and is unskilled and undisciplined in their
Dhamma, perceives earth as earth. Having perceived earth as earth, he
conceives himself as earth, he conceives himself in earth, he
conceives himself apart from earth, he conceives earth to be ‘mine,’
he delights in earth. Why is that? Because he has not fully understood
it, I say.
“He perceives water as water. Having perceived water as water, he
conceives himself as water, he conceives himself in water, he
conceives himself apart from water, he conceives water to be ‘mine,’
he delights in water. Why is that? Because he has not fully understood
it, I say.

Later, the Buddha contrasts the untaught ordinary person to the Buddha (the Tathagata):

“Bhikkhus, the Tathāgata, too, accomplished and fully enlightened,
directly knows earth as earth. Having directly known earth as earth,
he does not conceive himself as earth, he does not conceive himself in
earth, he does not conceive himself apart from earth, he does not
conceive earth to be ‘mine,’ he does not delight in earth. Why is
that? Because the Tathāgata has fully understood it to the end, I say.
“He too directly knows water as water ... Why is that?
Because the Tathāgata has fully understood it to the end, I say.

So, even the Buddha, who is fully enlightened and fully understood it to the end, perceived the reality of earth as earth, water as water, fire as fire etc. This is the undefiled perception of reality relative to the observer.
The only difference is that the Buddha has eliminated the mental idea of the self, which is the root of all objectification-classification / reification / papanca as explained in Snp 4.14 to be the cause of objectification and classification of non-self objects and their association with (the mental idea of) the self.
From Snp 4.14:

"He should put an entire stop to the root of
objectification-classifications: 'I am the thinker.'

The commentary by the translator states:

On objectification-classifications and their role in leading to
conflict, see Sn 4.11 and the introduction to MN 18. The
perception, "I am the thinker" lies at the root of these
classifications in that it reads into the immediate present a set of
distinctions — I/not-I; being/not-being; thinker/thought;
identity/non-identity — that then can proliferate into mental and
physical conflict. The conceit inherent in this perception thus forms
a fetter on the mind. To become unbound, one must learn to examine
these distinctions — which we all take for granted — to see that they
are simply assumptions that are not inherent in experience, and that
we would be better off to be able to drop them.

The commentary also briefly explains how this leads to suffering.
How is this related to Madhyamaka?
Madhyamaka teaches that all phenomena is empty of inherent substance, which is really the meaning or reality given to phenomena, by the mind, as a result of objectification-classification / reification / papanca. This is exactly the message of the Lump of Foam Sutta (SN 22.95).
But does reality REALLY REALLY REALLY exist?
Well, the Buddha answered that in AN 4.77 and the Parable of the Poisoned Arrow.
From AN 4.77:

"Conjecture about [the origin, etc., of] the world is an
unconjecturable that is not to be conjectured about, that would bring
madness & vexation to anyone who conjectured about it.

So, whichever way you slice Buddhist teachings, we find that any reality that matters is the one that is based on the observer. Any other reality is soteriologically irrelevant and also irrelevant to Buddhism.

I have no idea how you relate AN 4.77 to this question. To me they are totally different.

“Monks, these have the nature of birth, ageing, death, ceasing, and rebirth. Monks, all compounded things are as an illusion, a flame, ceasing in an instant; being not real they come (arise) and go (cease)." -> To me that is a straightforward answer. Reality doesn't exist. And it alludes to what I think is a sutta definitive in meaning: https://suttacentral.net/sn22.95/en/sujato

As to "Any other reality is soteriologically irrelevant and also irrelevant to Buddhism". I think it is a fact that such other reality is denied in Sabbe Sutta where it says that if someone were to propose existence of anything repudiating the six sense media & it's objects, it would not be possible. I have met a person who held the view that there maybe is some reality repudiating that of sensory percepience and held that it is either way not important, i am still not convinced you and him aren't the same person.

@YesheTenley No. SN 22.95 is talking about papanca. Form and the rest of the five aggregates are empty of the reality or meaning that is given to it by the mind, as a result of objectification-classification / reification / papanca.

He referred to that other reality as adhamma and maintained that ie space is such adhamma and that the nature of such things had nothing to do with the dhamma. He also had a boner for the word papanca. Is not a criticism but i think it's curious that two people have such similar views because it's quite rare to find two people familiar with the texts and arriving at a seemingly similar interpretation

@ruben2020 we disagree, but I will not argue it here. will give another answer. btw, i also find the line "any other reality is soteriologically irrelevant" to be utterly wrong. in fact, i think the exact opposite is the case... that any idea of reality is utterly non existent is the central and most important soteriological fact of the dhamma.

"reality that matters is the one that is based on the observer" = Solipsism


text:
What is The Prediction as defined by the Mahayana tradition?
Please see this section taken from the wiki page titled Boddhisattva which might help you answer the question:

...what early Mahayana sutras like the Aṣṭa do is to help individuals
determine if they have already received a prediction in a past life,
or if they are close to this point. The Aṣṭa provides a variety of
methods, including forms of ritual or divination, methods dealing with
dreams and various tests, especially tests based on one's reaction to
the hearing of the content in the Aṣṭasāhasrikā itself. The text
states that encountering and accepting its teachings mean one is close
to being given a prediction and that if one does not "shrink back,
cower or despair" from the text, but "firmly believes it", one is
irreversible. Many other Mahayana sutras such as the Akṣobhyavyūha and
the Śūraṃgamasamādhi Sūtra present textual approaches to determine
one's status as an advanced bodhisattva. These mainly consist in one's
attitude towards listening to, believing, preaching, proclaiming,
copying or memorizing and reciting the sutra. According to Drewes,
this claim that merely having faith in Mahāyāna sūtras meant that one
was an advanced bodhisattva, was a departure from previous Nikaya
views about bodhisattvas. It created new groups of Buddhists who
accepted each other's bodhisattva status.

Also, is the Śūraṃgamasamādhi Sūtra the same as Leng Yen Ching? And, is there an English translation of the Akṣobhyavyūha sutra?

A "prediction" is a statement made by an enlightened person, originally a previous Buddha, or, in Mahayana tradition, an enlightened master, that guarantees its object eventual attainment of enlightenment in a subsequent existence.

Is this similar to reaching stream entry in the Theravada tradition?

Yup, I think it is conceptually very similar. Not sure if it signifies exactly same level of insight or something higher or lower as stream entry, but it does mark a milestone in one's realization yes.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


text:
Is Chögyal Namkhai Norbu correct when he says our life is unreal and that Buddha taught that life is just like a dream?
In this video clip you can see renowned Tibetan master Chögyal Namkhai Norbu saying that life is unreal and that the Buddha taught it is just like a dream. Is he correct? I've transcribed below:

Sometimes we have very nice dream. Fantastic dream... And we enjoy. We
are very happy. We are dreaming, for example... ...I'm looking and
someone is selling... lottery ticket. Very, very big lottery. I am
taking and buying from someone and I am returning home. And I am
seeing the television. And when I am looking at my number... The
television is saying that number! Then I feel very happy. "Oh, what do
I do now?" All this money. I am really happy and then I wake up. When
I wake up, I discovered that is a dream, unfortunately. I am not
happy. Or sometimes... very, very bad dream. There are many people
that want to kill me. They are arriving in my house. Then they are
starting to kill me. I feel very afraid. That moment I wake up. And I
discover, "Oh, that is only a dream!" I am very happy. You see, good
or bad. Even good or bad. A dream is a dream. Unreal. So Buddha is
saying, our life is just like a dream. Big dream. Dream of night is a
very small dream, but... Our life's dream, it has many day and night,
day and night etcetera. When we discover that... Dreams, we discover
when we wake up. But big dreams, we discover... When we are dying and
being in a state of Bardo (transitional state).

Emphasis mine.
A closely related question (with answers) is here.

It might be possible for you to gain the understanding you need from these two powerful excerpts. The first is from the Phena Sutta; the second is from chapter 32 of the Diamond Sutra.

The Phena Sutta
Form is like a glob of foam;
feeling, a bubble;
perception, a mirage;
fabrications, a banana tree;
consciousness, a magic trick —
this has been taught
by the Kinsman of the Sun.
However you observe them,
appropriately examine them,
they're empty, void
to whoever sees them
appropriately.

[ADDITION]
How can the Phena Sutta be describing something that is dream-like? The aggregates give their fascination over to form-based ideas such that they develop an unhealthy reliance on those ideas. This is called clinging. Clinging presents itself in two ways: attraction and aversion. It is not objects that we cling to, but it originates from our interpretation of those objects; the way in which those objects are cognized. Therefore, the clinging is always from that origin: the mind - the neurotic mind clings to the body. It is this motion of aversion and attraction that creates a noisy haze in our consciousness, stimulated by feeling/perception. This is pananca. This haze hinders our view; we don't see clearly. This not seeing clearly is avijja from which suffering arises. The experience of suffering is a method by which the body tries to eject wrong views born from that very ignorance, but we misperceive its function. Suffering then becomes an identity instead of knowledge. This is how the aggregates can present themselves as dream-like. It's just another way to speak about ignorance. It doesn't matter how you word it. If dream is suitable for you, then fine, as long as you understand the mechanisms behind it.

The Diamond Sutra
“Subhuti, how can one explain this Sutra to others without holding in
mind any arbitrary conception of forms or phenomena or spiritual
truths? It can only be done, Subhuti, by keeping the mind in perfect
tranquility and free from any attachment to appearances.”
“So I say to you – This is how to contemplate our conditioned
existence in this fleeting world:”
“Like a tiny drop of dew, or a bubble floating in a stream; Like a
flash of lightning in a summer cloud, Or a flickering lamp, an
illusion, a phantom, or a dream.”
“So is all conditioned existence to be seen.”
Thus spoke Buddha.

Amazing answer. Bravo!

To add to this I'd also recommend Aṣṭasāhasrikā Prajñāpāramitā Sūtra the one in 8000 lines being the most accessible.

I concur. The Perfection of Wisdom isn't fooled by conditionality. ;-)

The excerpt I provided does immense justice to the dhamma. What extra things would you like me to include?

The Pali suttas are almost the same as Mahayana agamas in Sanskrit, and so would be on-topic as Mahayana-relevant content.
From Dona Sutta, the Buddha calls himself "awakened":

"Just like a red, blue, or white lotus — born in the water, grown in
the water, rising up above the water — stands unsmeared by the water,
in the same way I — born in the world, grown in the world, having
overcome the world — live unsmeared by the world. Remember me,
brahman, as 'awakened.'

This means he has awakened from a dream of course.
Awakening from the dream does not mean that the world is a dream or that the world is unreal.
It's because the dreamer (the self) is unreal, as the Buddha taught that all phenomena is not self (sabbe dhamma anatta - Dhp 279).
Upon waking from the dream, the dreamer disappears in this case. Also all reification/ objectification-classification/ papanca arising from the self - non-self duality is the dream that disappears.
The chair however doesn't disappear and the Buddha can still sit on it.
From Vina Sutta:

"In the same way, a monk investigates form, however far form may go.
He investigates feeling... perception... fabrications...
consciousness, however far consciousness may go. As he is
investigating form... feeling... perception... fabrications...
consciousness, however far consciousness may go, any thoughts of 'me'
or 'mine' or 'I am' do not occur to him."

From Tuvataka Sutta:

"I ask the kinsman of the Sun, the great seer,
about seclusion & the state of peace.
Seeing in what way is a monk unbound,
clinging to nothing in the world?"
"He should put an entire stop
to the root of objectification-classifications:
'I am the thinker.'

The translator commented:

On objectification-classifications and their role in leading to
conflict, see Sn 4.11 and the introduction to MN 18. The perception,
"I am the thinker" lies at the root of these classifications in that
it reads into the immediate present a set of distinctions — I/not-I;
being/not-being; thinker/thought; identity/non-identity — that then
can proliferate into mental and physical conflict. The conceit
inherent in this perception thus forms a fetter on the mind. To become
unbound, one must learn to examine these distinctions — which we all
take for granted — to see that they are simply assumptions that are
not inherent in experience, and that we would be better off to be able
to drop them.

This question was tagged as Tibetan Buddhist and although the Pali scriptures are relevant to Mahayana, I think this answer is from the perspective of the Theravada and as such is not appropriate.

But dreams are real—when you are dreaming, you are really dreaming. But their contents are not (always) true. They are like a movie, which is something you can watch, but the movie’s contents—the actors, and the action, and even often the setting—are not true. This comparison just like is not saying two things are identical, it’s comparing one thing—our life in this case—to an evident particular characteristic of the thing it’s being compared to—a dream in this case. A dream is illusory, but you really dreamed it, and it is this characteristic of being illusory that our life is being compared to. But you are truly living. It’s just that there is something illusory about the actors—they seem like they are truly separate beings, but they have no independent self nature; and there is something illusory about the action—it seems as if there is something happening to you, but your intrinsic awareness (he was teaching the view of Tibetan Dzogchen) is not changed in any way by what is happening; and even the location is illusory—every quality you believe is a quality of the world around you is something that is of you, and not otherwise (for example, you see red, but what you believe is red is just how your eyes perceive what is there).
So our lives are real—we are truly living—but everything that happens in them is illusory in some way. That’s what Chögyal Namkhai said. You only thought he said your life is unreal. He said (that Buddha said) that it is like a dream, and the salient characteristic of a dream is that its contents are illusions—seemingly real while you are really dreaming, but then discovered to have been illusory.
Addendum (to answer Yeshe Tenley's request for a definition in the comments below):
To be real, something must be non-contingent, necessary, simple, and evidenced.
Non-contingent, means that it cannot be dependent on anything else in any way. It can’t be brought into being, caused, or created, for example, and it certainly can’t depend on you experiencing it for its reality.
Necessary, means what it says. What is real must be necessary—like a motor in a car, or a charge in its battery—or nothing works. What is real cannot be an option that one can take or leave, something gaudy to set our car apart from those of others.
Simple, means it is not a collection of parts; it is not a union of aspects—it is not structured in any way. The reason for this is that if a thing isn’t simple then it depends on something else to cause it, or make it, to be, and so it is contingent.
Therefore, what is real is necessarily non-dual.
And finally, what is real must be evidenced. If a thing isn’t directly evidenced—since I am asserting that it doesn’t exist, i.e., it can’t be experienced—if it is just inferred, hypostatized, or hypothesized, than it’s not real.
When I say that something exists, or I talk about existence, I mean that imperience is happening, could happen, or did happen. And that is all I am saying, having already seen that the contents of experience were ephemeral at best and certainly lacked any inherent self-existence, how can I assert that any of it is real?
Please note, imperience is a technical word for me; we imperience a dream, but experience its content.
This is taken from my article, "Reality and Existence" and the longer subject of what I mean by imperience and experience is another article "Understanding Experience" which is very relevant to this question, but a decently long read.

Is there a difference between having a dream and what the dream was about? Clearly, if you wake up from a dream soaked in sweat, or with other physical symptoms, it is not correct to say that you weren't dreaming; but what you were dreaming was not really happening. That is the distinction that I honestly feel that CN was trying to make with his imperfect English. I know this to be correct because what you are taking away from his use of "unreal" is not to be found in Dzogchen teachings. Don't accept what I say, if it goes against your intuition; but remember all intuitions are not correct.

Ah, I see you deleted the comment that I just responded to ☺

No, not at all. You have made the mistake, not him.

But there is only emptiness... nothing to be unreal.

Apparently, you didn’t ask the question in good faith then. Since you already know that he said what you understand to be the case.

The point is that when we look out into the world and we see (say) a tree, a dog, a car, a white cloud, or whatever you like, what we're actually perceiving is color, shading, texture, apparent movement... We receive this great wash of ambiguous sensation, and in our heads we establish boundaries, conjure up structures and patterns, intuit relationships, and fit these sensations into concepts, discarding most of the sensations that got us there. We then treat these conceptual objects as though they were part and parcel of the real world, instead of fabrications we impose on the real world after-the-fact.
When we sleep these concepts sometimes float free of any referent and appear to us as dreams, but seeing a dog running in a dream and seeing a dog running in a field is merely a matter of degree. Both have that 'dream-like' quality of a conceptualization that is at best loosely connected to anything material.

Fwiw Buddha compared sensuality to a dream as well. I don't think this tenet of the Dhamma is central to it because it is still open to be interpreted in favor of an eternal & underlying consciousness doing the dreaming.
As i see it, the latter point not being thus interpreted is the central tenet and what separates the Dhamma from eternalism.

Ahh, you are correct we are not real either.  That is key to understanding and without it some can drift into the confusion of eternalism.

Also this support from Dhp

One who looks upon the world as a bubble and a mirage, him the King of Death sees not.
Dhp 170

I doubt a Buddha would ever teach life is like a dream. Such a teaching may cause people to act in life nihilistically with negligence, such as Tibetan gurus who engage in sexual misconduct.
In MN 54, the Buddha taught sensual pleasures are like a dream. In Thig 14.1, Subha the nun said being beguiled by a woman painted with make-up is like a dream.
But in AN 3.136, the Buddha taught conditioned things have a fixed quality, in that they are impermanent, unsatisfactory & not-self. Seeing all conditioned things are unsatisfactory is not like a "dream" because dreams can imagine things to be pleasurable or satisfactory.
Also, Nibbana is an experience of those who have lived the Holy Life. In MN 140, the Buddha said Nibbana was "undeceptive" and "true", which, again, is not a "dream".
In MN 29 & MN 30, the Buddha taught the essence of the Holy Life is the unshakeable freedom of mind. This Holy Life is not a dream because Nibbana is permanent and undeceptive.

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text:
What is the doctrinal justification for Shaolin martial arts?
It is known that Shaolin monks practice a form of Chan Buddhism. It is also known that they practice their own form of martial arts.

What is the doctrinal justification for their practice of martial arts?

Additionally/alternatively, within the Shaolin view of Buddhism, are martial arts purported to have soteriological effect?

Lastly, as a bonus, are there any academic studies exploring the Shaolin doctrines?

I found an answer regarding their practices in general, but not about the doctrinal basis.
Thanks.

From the little I've read, there's a legend that Boddhidarma taught the martial art in the 5th century to monks of the Shaolin monastery, so they could defend themselves from bandits and animals.
There may be some doctrinal justification, for that motive and that behaviour -- I think that the Theravada Vinaya says that if a monk is captured he can "strike a blow, desiring freedom".

There's also an academic essay -- Epigraphy, Buddhist Historiography, and
Fighting Monks: The Case of The Shaolin Monastery -- which says there's epigraphic evidence that monks also participated on the battlefield, I presume with weapons, in aid of this or that claimant to the throne.

Moreover, the events they record are
not mentioned in Buddhist historiography either. The monks that compiled the voluminous section of the Buddhist canon that is devoted to
history were loath to discuss monastic involvement in warfare, for it
contradicted their religion’s prohibition against violence. Buddhist authors preferred to ignore instances, such as those attested at Shaolin,
in which monks resorted to arms. Thus, Shaolin epigraphic sources
shed invaluable light on a topic ignored by Buddhist historiography:
monastic warfare.

I think that's harder to justify from what I know of Buddhist doctrine.

It was this military and administrative center that the
Shaolin monks conquered, earning them the gratitude of the future
Tang emperor.
Pei Cui does not allude to a Tang-government request that the
monks confront Wang Shichong. His chronicle suggests that it was
their initiative to attack the Sui rebel. The monks certainly resented
Wang, who had robbed them of their estate. However, strong as their
resentment was, political calculations also contributed to their military action. Pei notes that “monks Zhicao, Huiyang, Tanzong, and the
others examined to which of the contending parties divine grace was
directed.” The Shaolin clerics probably did not debate the respective
spiritual merits of the Tang rulers and Wang Shichong, but rather who
was more likely to win the war. Had they wagered on the wrong party
this would have been detrimental to their monastery. Instead their
choice of the Tang dynasty guaranteed the prosperity of the Shaolin
temple for centuries to come.

Some attempts at doctrinal justification is that the practice develops "energy" (virya), and that it's good to defend the Three Jewels (that is according to an unreferenced sentence on Wikipedia).
There are some related topics on this site (based on other forms of Buddhism), for example

Can Buddhism give any justification for military violence?
What does Buddha and Buddhism say about fighting against enemy of dharma?

SN35.88:13.1: “But if they do stab you with a knife, what will you think of them then?”
SN35.88:14.1: “If they stab me with a knife, I’ll think:
SN35.88:14.2: ‘These people of Sunāparanta are gracious, truly gracious, since they don’t take my life with a sharp knife.’
SN35.88:14.3: That’s what I’ll think, Blessed One.

I studied Rinzai Zen under Tanouye Roshi. Although not Shaolin, the Chozen-Ji temple is aligned with Zen/Chan and the martial arts. As Tanouye Roshi explained, Zen improved a warrior's skill with its equanimity in the face of death. A doctrinal quote for that equanimity is given above.
Paradoxically, a warrior's livelihood is about killing, which is definitely NOT Buddhist doctrine:

MN8:12.3: ‘Others will kill living creatures, but here we will not kill living creatures.’

So why then did I study Zen and the martial arts?
I studied Zen and the martial arts to understand how NOT to kill. Musashi, that great warrior, became a farmer. Like Musashi, Tanouye Roshi was a master of the sword and his doctrine was to give the world fearlessness as his greatest gift. Tanouye Roshi was also one of the gentlest, kindest persons I have ever met. He taught me how to put down the sword.

MN86:5.9: “I’ve stopped, Aṅgulimāla—now you stop.”

And finally:

SN1.71:2.3: What’s the one thing, Gotama, whose killing you approve?”

I'll let you look that up...

Musashi chose to fight most of his duels with a wooden sword, against steel, also.


text:
Is the word 'real' synonymous with 'exists' in Buddhist doctrine?
Are these two words synonymous? Is everything that exists, real? Is everything real, an existent? What is a proper relationship between the words "real" and "exists" in the context of Buddhist doctrine? What is a proper definition of "real" and of "exists" in the context of Buddhist doctrine?
Are dreams real? Do they exist? Are illusions real? Do they exist? Are chairs real? Do they exist? Are persons real? Do they exist? Is the son of a barren woman real? Do they exist? Is there anything that is real, but does not exist?
What do we really mean when we say something is real? Pun intended.

This question appears to me to be a reference to some aspect (or translation) of a Mahayana doctrine which some people would be already familiar with (perhaps see Posts containing 'existent' for example).

I think the word used in the sutta which is closest to "real" is often ''true''. Eg the four noble truths can be expressed as the reality of suffering, the reality of it's conditioning, the reality of it's cessation and the reality of the path leading to the cessation.

In the conventional truth, mirages exist and are real as a mirage but not real as water. Dreams exist and are real as dream but not as a play in a theater.
So there is nothing which can be said conventionally existing but unreal because it is real in that way it is called to exist.
Conventionally existent Buddhas alleviate the conventionally existing suffering of conventionally existent sentient beings.
The suffering sentient beings are conventionally existent and are also conventionally real.
Conventionally existent Buddhas however don't alleviate the conventionally unreal and nonexistent suffering of the son of a barren woman.
I think this answer by @Tenzin Dorje to a related question may be relevant too.

This is great and @Tenzin Dorje's answer is stupendous. I believe my answer is totally in accord with both, but if it is not then it's my fault.

Hmm, Epic, I wonder about the third sentence though. I think it is in disagreement with the knowledge of the world. IOW, it is quite common and conventional to say that dreams are unreal. To tell your child not to worry because the movie isn't real, etc.

There are 2 objects of knowing...

Reality (yathabhūta) - the existent without imagination.

Imagination (sammati,smaññā) - the conception which appearing only while imagining.

We are knowing both switching rapidly. Trillion times of mind moment in a second, there are many moment knowing realities and many moment imagining  imaginations switching rapidly. We see many realities such as colors, voices, smells, tastes, tempture or hardness or motion, then we imagine "this is piece", "this is loaf", "This many loaf is body", "this body is me", etc.
Reality can be exist without imagination, but imagination never exist and never arise, only concept.

There are 2 realities...

Saṅkhata - causes & their effect which constructing, conditioning each others to arise and to vanish. This is exist only when it arising. See SN. SaṅkhataLakkhaṇaSutta. It is exist only when arising, but it is real in every right recalling.

Asaṅkhata- Nibbāna, the opposite of Saṅkhata.  This is exist forever, but it is neither arising nor vanishing because it is the opposite of Saṅkhata.

Ther are 3 existents...

real existent - Saṅkhata and Asaṅkhata.

right imagined existent - the imagination which imagined by any mind without wrong-view-clinging about the reality which really possible to arise and to vanish (saṅkhāra) or to be (nibbāna).

wrong imagined existent -  the imagination which imagined by wrong-view-clinging about the misunderstood of reality, wrong causes and wrong effects in of trillions times arising in a second moment. For the example, when we are reading this answer, we read it by wholesome, unwholesome, resultant, and neither-wholesome-nor-unwholesome-minds switching rapidly. There also are many
trillions of object pass trough the senses as well. However, we imagine they are only a wholesome mind, only an object, only me, one body from birth, etc. This is imagination.

There are deeply uncountable detail of the truth. This is why the concentration meditation is still important in Tipitaka, although the insight meditation is the way to see the truth. The deeply and variant detail makes the insight meditation hard to control without the concentration meditation for the practitioner who has low skill of 10 perfections (Pāramī).

Whether we can differentiate the word exist from real is only for the mind's playground, and that is the key word: the mind is that which creates the idea of existing and the idea of what is real from its concept of itself as the body looking out into the concept of the world. It's like an illusion looking back onto itself for a remedy to that illusion only to delve deeper into its own illusion. In simple terms those words (real & exist) are placeholders for consciousness to find a convenient footing which turns out to be a cyclic, neurotic and fruitless endeavour. Those consciousness-based things rise and fall, almost as if converging within a narrow aperture of time we call now and then confining itself to the annals of our memories. What about that now part? Could that be real? Could that exist? Not at all. Anything that passes through that now-ness has already fallen away.
Therefore, the words real and exist might be better understood as avijjā or ignorance. This is not to say that there is nothing, but that the six-sense consciousnesses are not the resting place for wisdom-understanding - rather, the six-sense consciousnesses have form-becoming as their self-governing impetus.
To a Puthujjana or a struggling noble one, this can easily be mistaken as a solipsistic view. You can read my answer here about why suffering is still acknowledge by an enlightened mind thus refuting the ideas of solipsism.
Back to the answer, there's a great book called Mae Chee Kaew and in that book is a section you might like about how she suddenly comes to understand that what her mind created only appeared to be real, only appeared to exist. See if the wisdom here calls out to you.

Spontaneous Awarenes - Page 184
Mae Chee Kaew’s meditation had reached a decisive phase in body
contemplation, a turning point in which the root-cause of the mind’s
attachment to bodily form was seen in stark clarity. As instinctive
feelings of revulsion reunited with their primary cause, a profound
realization suddenly occurred: the mind itself produced feelings of
revulsion and attraction; the mind alone created perceptions of
ugliness and beauty.
Those qualities did not actually exist in the objects of perception. The mind projected those attributes onto the images it perceived, and
then deceived itself into believing that the objects themselves were
beautiful and attractive, or ugly and repulsive.
In truth, the flow of consciousness was consistently steeped in a
proliferation of mental imagery and attending emotion. Her mind
painted elaborate pictures all the time — pictures of herself and
pictures of the external world. It then fell for its own mental
imagery, believing it to be substantially real.
At that stage, the infinite, space-like awareness of mind essence and
the particularity of conscious perception were operating
simultaneously.
Gradually the illusion of cohesive mental images began to break down
as well. Within the flowing current of consciousness, myriad amorphous
forms and fragmentary shapes arose, coalesced into images, and then
broke apart immediately, only to regroup and disband time and time
again. No sooner did an image of the body appear than it vanished
instantly.
Before a particular desire or expression could fully formulate, the
source of awareness simply enveloped it, causing it to dissolve into
emptiness and disappear. Countless potential ways in which body and
mind could express themselves seemed to arise in random succession,
only to dissolve into emptiness, one after another.
Habitual concepts of bodily existence expressed a desire to take form
and declare their individual characteristics, but the knowing essence
dissolved them all before they could establish a definite presence in
the mind.
This insight occasioned a momentous revolution of Mae Chee Kaew’s
entire being. She understood the truth with absolute certainty:
delusion about imagery produced by the flow of consciousness leads to
feelings of repulsion and attraction.
She realized that both were rooted in a deeply instinctive, but almost
subliminal, distortion of conscious perceptions of body and form. When
the real basis of those perceptions was exposed, completely
undermining their validity, the external world of appearances
collapsed, and her attachment to it ceased of its own accord.
With the cessation of all images created by the mind, came the
cessation of attachment to form. Once her mind had withdrawn
completely from all sensual involvement, a feeling of profound
serenity enveloped her entire mental being.
Finally, for Mae Chee Kaew, bodily images, even as bare forms, no
longer existed within her mind’s conscious framework. Since no shapes
or forms remained in the mind to be grasped, Mae Chee Kaew knew she
could never be reborn in the realms of form again.
The mind’s usual sense of physical limitation and embodiment
completely disappeared. She felt her being dissolve, expand outward
and merge with all things, as though forming one essence with the
universe; resting within, unfettered by any dependency, was a supreme
emptiness — clear, bright and still."
Mae Chee Kaew pdf book
(Also an audio version here)

Allowing this radical change to come to the fore does not mean that one must sit on a zafu cushion, although that's helpful. In every waking moment it is possible to realise what is real through a practice called non-objectless awareness taught by Hongzhi Zhengjue but originating from the Buddha. From this practice comes a silent illumination brought about by the relinquishing of form-based consciousnesses and the best part: it can be done anywhere, at anytime and completely impromptu. It is a moving into the unadulterated, all-inclusive field of in the seeing, there is just seeing... without being clouded by concepts, grasping, clinging and duality. The Buddha teaches this to Bahiya thus:

"Herein, Bahiya, you should train yourself thus: 'In the seen will be merely what is seen; in the heard will be merely what is heard; in the
sensed will be merely what is sensed; in the cognized will be merely
what is cognized.' In this way you should train yourself, Bahiya.
"When, Bahiya, for you in the seen is merely what is seen... in the cognized is merely what is cognized, then, Bahiya, you will not be
'with that.' When, Bahiya, you are not 'with that,' then, Bahiya, you
will not be 'in that.' When, Bahiya, you are not 'in that,' then,
Bahiya, you will be neither here nor beyond nor in between the two.
Just this is the end of suffering."

"Suffering is real.” Atthi kho, kassapa, dukkhan’ti. SN 12.17

knows & sees things as they really are -  yathābhūtaṁ jānāmi passāmī - AN 11.2

what is "cognized" appears to include "concepts". It appears you are stretching the reality of the Bahiya Sutta and making it conform with your Solipsism

Thanks. I agree with these suttas, but the teachings are meant to be short and sharp. That is why they are delivered in that way. Constantly linking suttus is not always helpful. One can fall into an endless, maddening Mandala of suttas.

Hi Neuromax, there is a lot to like in this answer, but it doesn't really give any def. and to my initial reading it appears to use 'real' and 'exists' synonymously which I think is an error. Also interesting you think the refutation of solipsism has to do with the 'real' existence of suffering? Anyway, see my answer if you want an alternative def.

@Yeshe Tenley - yes, it's tricky to extrapolate the behind-the-scenes-truth just like it often is with the suttas. For a craving mind the meaning of the words only point to more words with more meanings. In short, the mind isn't satisfied with reading words that don't reciprocate the formation of more words. However, you might be searching for a strictly academic answer. Nothing wrong there. ;-)

The Pali suttas are almost the same as Mahayana agamas in Sanskrit, and so would be on-topic as Mahayana-relevant content.
From DN 17:

See, Ānanda! All those conditioned phenomena have passed, ceased, and
perished. So impermanent are conditions, so unstable are conditions,
so unreliable are conditions. This is quite enough for you to become
disillusioned, dispassionate, and freed regarding all conditions.

The Buddha was not concerned whether a chair is real or not. He only noted all such conditioned and compounded things as impermanent, unstable and unreliable.
If by "unreal", you mean that a chair is impermanent, unstable, unreliable, conditioned and compounded, then we can say that the chair is unreal.
However, if by "unreal" you mean the chair doesn't exist, then it's not acceptable, because according to MN 1 below, a Buddha (who is fully enlightened and fully understood it to the end) sees earth as earth, water as water, fire as fire etc. He sees things as they are. In other words, they exist, even if only for one moment.
From MN 1:

“Bhikkhus, the Tathāgata, too, accomplished and fully enlightened,
directly knows earth as earth. Having directly known earth as earth,
he does not conceive himself as earth, he does not conceive himself in
earth, he does not conceive himself apart from earth, he does not
conceive earth to be ‘mine,’ he does not delight in earth. Why is
that? Because the Tathāgata has fully understood it to the end, I say.
“He too directly knows water as water ... Why is that?
Because the Tathāgata has fully understood it to the end, I say.

I am emphatically not stating that "if by "unreal" you mean the chair doesn't exist, then it's not acceptable." And this is a great answer, but unfortunately I don't think "impermanent, unstable, unreliable, conditioned and compounded" is a very good def. of 'real'

Also, https://suttacentral.net/sa273/en/choong has “Monks, these have the nature of birth, ageing, death, ceasing, and rebirth. Monks, all compounded things are as an illusion, a flame, ceasing in an instant; being not real they come (arise) and go (cease)." Emphasis on "being not real" as the specific characteristic in which he is drawing an allusion to an illusion and a flame. A chair is a compounded thing, right? If so, then I'd say this is an example of the Buddha caring enough about whether a chair is real to specifically call it out as not real. :)

@YesheTenley This is good. According to SA 273 then, compounded things are an illusion because they are impermanent. So, then it's ok if you define "unreal" as "impermanent, unstable, unreliable, conditioned and compounded."

Yes, I think you can define it that way and it is somewhat workable, but I think the Buddha had something more in mind. He used an 'illusion' specifically because it is unreal. And the thing about an illusion is that it does not exist as how it appears. And it is easy for people to see this and understand this. That is what I think 'real' means... something that exists exactly as it appears. And I think the Buddha was specifically drawing out and referring to this characteristic.

IOW, impermanent, unstable, unreliable, conditioned and compounded are all characteristics of illusions sure, but the thing that makes illusions stick out is the very clear unreality of them. That they appear to exist one way and yet they utterly do not exist in the way that they appear. They are a magic trick. They are deceptive in appearance. People have an easy time seeing this with regard to illusions, but not so easy a time seeing this with regard to chairs :)

I think the historical Buddha was very pragmatic and focused on his objective, which is ending suffering. He was not interested in exploring metaphysics or discovering the principles of particle physics.

We are in agreement there. There is no daylight between us on that.

This definition isn't the most rigorous I could give, but it is workable - I think - and may help others navigate around the thickets of uncomfortable emotions this question might bring up. Maybe others can help improve these definitions!
Exists: Something which can be known (perceived/conceived) to an awareness.

Real: Something that exists, but is not deceptive in its appearance. ie., it exists exactly how it appears.

So let's go through the questions with these preliminary definitions in mind and see how they fit.
Are these two words synonymous?
Obviously not.
Is everything that exists, real?
Nope! Examples incoming...
Is everything real, an existent?
Yep! If it is real, it must exist.
What is a proper relationship between the words "real" and "exists" in the context of Buddhist doctrine?
Probably the most important thing to know is that if you deny something is real it does not automatically mean you deny that it exists. This is ruling out naive nihilism.
What is a proper definition of "real" and of "exists" in the context of Buddhist doctrine?
Well, I've just given my def. haven't I. NOTE: I'm not claiming these def. are the end all be all of def. nor that they are infallible or somehow the one-true-definitions. But I think they are workable for most contexts and accord with the way normal people speak.
Are dreams real?
Nope.
Do they exist?
Yep.
Are illusions real?
Nope.
Do they exist?
Yep.
Are chairs real?
From the perspective of the world they sure are. From the perspective of an Arya being. Nope.
Do they exist?
Of course! How absurd would it be for me to say that chairs don't exist. Come on! :)
Are persons real?
Same answer for chairs.
Do they exist?
Same answer for chairs.
Is the son of a barren woman real?
Of course not.
Do they exist?
Please. How can they possibly exist! It is a paradoxically def!
Is there anything that is real, but does not exist?
That's a hard no.
What do we really mean when we say something is real? Pun intended.
Usually people bring all kinds of metaphorical baggage when speaking of 'real' and 'exists' that comes when the ego feels threatened. Often times people will use them synonymous, but when confronted with the obvious absurdities this entails (that dreams are real or alternatively that they somehow don't exist) they'll retreat into highly contrived definitions that also entail obvious absurdities. Others will lament the whole question and insist that the question itself shouldn't be dealt with. Like somehow defining 'real' and 'exists' will lead to madness. Again, that's the ego feeling threatened.
What people really mean when they are really invested in sticking up for the really real existence of things is that their own I is feeling really really threatened and how dare anyone even begin to question the really really really really concrete and clear existence of things.
PS: The above answer was intended to come across as lighthearted and humorous. If it doesn't read that way, then it is only due to the poor communicational ability of the author of the answer.

I think the question is concerning 'Conventional truth' because in the ultimate truth existence and reality have no meaning. However, in the Conventional truth, all conventionally existing things are also real and there are no unreal conventionally existing things.

Conventional truth that which is conventionally real and existing
Conventional falsehood that which is conventionally unreal and non-existing

A mirage is conventionally 'real and existing' as light rays bend via refraction, but the water perceived in the mirage is not conventionally 'real and existing'.
A dream is also conventionally 'real and existing' as a work of the mind, but the death of your partner in a car accident in your dream is not conventionally 'real and existing.
So if someone says 'I had a dream like MLK, and someone else says 'Dreams are not real' what he/she is saying is that the story in the dream is not conventionally real, they are not claiming that MLK didn't dream. Because dreams as a phenomenon of the mind are conventionally 'real and existing'.

I wonder about this, "all conventionally existing things are also real" ... this seems to me to be in contradiction or opposed to the way normal people speak. As you note, people say 'Dreams are not real' in everyday language of the world. People also say dreams exist in everyday language of the world. The 'death of your partner in a dream' doesn't exist? Then how do you perceive something that is non existent as opposed to say the son of a barren woman?

Well, the dream is real and it exists for the dreaming mind, but once your friend is awake then it is correct to say that what he dreamed (i.e the death of his partner) doesn't exist because at that moment it doesn't exist to any mind.

It's akin to someone with an impaired eye who sees a floating object, for him these floating objects are real and existing but once his sight is repaired, then the objects are not real and also don't exist. It would be very strange to say to the sick man the things he sees are not real but do exist because for his mind they are real and existing.

All the above is of course "conventionally!"

A way to think about this is that in the context of the doctrine of self then the Buddha is real but we won't be able to pin down the Buddha as a truth or reality and it is therefore a false doctrine precisely because we can't pin a Buddha down as a truth or reality.

What do you think, Anuradha: Is form constant or inconstant?"
"Inconstant, lord."
"And is that which is inconstant easeful or stressful?"
"Stressful, lord."
"And is it proper to regard what is inconstant, stressful, subject to change as: 'This is mine. This is my self. This is what I am'?"
"No, lord."
"Is feeling constant or inconstant?"
"Inconstant, lord."...
"Is perception constant or inconstant?"
"Inconstant, lord."...
"Are fabrications constant or inconstant?"
"Inconstant, lord."...
"Is consciousness constant or inconstant?
"Inconstant, lord."
"And is that which is inconstant easeful or stressful?"
"Stressful, lord."
"And is it proper to regard what is inconstant, stressful, subject to change as: 'This is mine. This is my self. This is what I am'?"
"No, lord."
"What do you think, Anuradha: Do you regard form as the Tathagata?"
"No, lord."
"Do you regard feeling as the Tathagata?"
"No, lord."
"Do you regard perception as the Tathagata?"
"No, lord."
"Do you regard fabrications as the Tathagata?"
"No, lord."
"Do you regard consciousness as the Tathagata?"
"No, lord."
"What do you think, Anuradha: Do you regard the Tathagata as being in form?... Elsewhere than form?... In feeling?... Elsewhere than feeling?... In perception?... Elsewhere than perception?... In fabrications?... Elsewhere than fabrications?... In consciousness?... Elsewhere than consciousness?"
"No, lord."
"What do you think: Do you regard the Tathagata as form-feeling-perception-fabrications-consciousness?"
"No, lord."
"Do you regard the Tathagata as that which is without form, without feeling, without perception, without fabrications, without consciousness?"
"No, lord."
"And so, Anuradha — when you can't pin down the Tathagata as a truth or reality even in the present life — is it proper for you to declare, 'Friends, the Tathagata — the supreme man, the superlative man, attainer of the superlative attainment — being described, is described otherwise than with these four positions: The Tathagata exists after death, does not exist after death, both does & does not exist after death, neither exists nor does not exist after death'?"
"No, lord."
"Very good, Anuradha. Very good. Both formerly & now, it is only stress that I describe, and the cessation of stress."

This is opposed to the truth & reality of the inferable elements which are experimentally verifiable.
Eg

we know that eye is by itself not seeing but there is no seeing without an eye
we know that visible medium is by itself not seeing but there is no seeing without the seen (ie a person can not see if there is no light.
we know that consciousness is not seeing but there is no seeing without consciousness, an unconscious person doesn't see even if you shine light in that eye

Only when there is a meeting of the eye, that which is visible to the eye and eye consciousness is there seeing, therefore contact is real and pinned as a true statement about that which we are thinking about.

Bhikkhus, there are these four kinds of clinging. What four? Clinging to sensual pleasures, clinging to views, clinging to rules and observances, and clinging to a doctrine of self.

One who clings to this doctrine comes to ask questions like does the Buddha exist after death and etc

Just wonderful.

I think so too, the anuradha sutta is one of the most awesome pieces of information in existence.

like marvel heroes exist in dependence on the context of the doctrine of the marvel universe but are unpinnable as a truth & reality and if someone went looking for xmen in their backyard it would be a case for a psychiatrist