Should we consider $\mathsf{P} \neq \mathsf{NP}$ a law of nature? Many experts believe that the $\mathsf{P} \neq \mathsf{NP}$ conjecture is true and use it in their results. My concern is that the complexity strongly depends on the $\mathsf{P} \neq \mathsf{NP}$ conjecture.
So my question is:

As long as the $\mathsf{P}\neq\mathsf{NP}$ conjecture is not proven, can/should one consider it as a law of nature, as indicated in the quote from Strassen?
Or should we treat it as a mathematical conjecture
that maybe proved or disproved someday?

Quote:

&quot;The evidence in favor of Cook's and Valiant's hypotheses is so overwhelming, and the consequences of their failure are so grotesque, that
their status may perhaps be compared to that of physical laws rather than that of ordinary mathematical conjectures.&quot;
[Volker Strassen's laudation
to the Nevanlinna Prize winner, Leslie G. Valian, in 1986]

I ask this question when reading the post Physics results in TCS?.
It is perhaps interesting to note that computational complexity has some similarities to (theoretical) physic: many important complexity results
have been proved by assuming $\mathsf{P} \neq \mathsf{NP}$, while in theoretical physic results are proven by assuming some physical laws.
In this sense, $\mathsf{P} \neq \mathsf{NP}$ can be considered something like $E = mc^2$.
Back to Physics results in TCS?:

Could (part of) TCS be a branch of natural sciences?

Clarification:
(c.f. Suresh's answer below)

Is it legitimate to say that the $\mathsf{P}\neq\mathsf{NP}$ conjecture in complexity theory is as fundamental as a physical laws in theoretical physics (as Strassen said)?
Strassen's statement needs to be put into context. This was an address to an audience of mathematicians in 1986, a time when many mathematicians did not have a high opinion of theoretical computer science. The complete statement is


  For some of you it may seem that the theories discussed here rest on weak foundations. They do not. The evidence in favor of Cook's and Valiant's hypotheses is so overwhelming, and the consequences of their failure is so grotesque, that their status may perhaps be compared to that of physical laws rather than that of ordinary mathematical conjectures.


I am sure that Strassen had had conversations with pure mathematicians who said something along the lines of 


  "You're basing the whole of complexity theory on a house of cards. What if P=NP? Then all your theorems will be meaningless. Why don't you just put forth a little effort and prove that P$\neq$NP, rather than keep building a theory on such weak foundations."


In 2013, when P$\neq$NP has been a Clay prize problem for a dozen years, it may seem difficult to believe that any mathematicians actually had such attitudes; however, I can personally vouch that some did. 

Strassen continues by saying that we should not give up looking for a proof of P$\neq$NP (thus indirectly implying that it is indeed a mathematical conjecture): 


  Nevertheless, a traditional proof would be of great interest, and it seems to me that Valiant's hypothesis may be easier to confirm than Cook's... 


so maybe I would label it as a "working hypothesis" rather than a "physical law". 

Let me finally note that mathematicians also use such working hypotheses. There are a large number of mathematics papers proving theorems whose statements run "Assuming the Riemann hypothesis is true, then ...".