Do Fetuses have souls? Is the aquisition of a soul instantenous or continuous? Christian fundamentalists argue against abortion on the grounds that fetuses have souls.  The argument starts with two premises: that people have souls while animals do not, and that the right to life goes with possession of a soul. 

It proceeds by asserting that the developing fetus must acquire its soul at some instant; and because no point after conception is special enough to be that instant, it must happen at conception. (It takes hours for an egg and a sperm to unite, but they could choose some brief part of the process as the crucial "instant".)  Therefore, the argument concludes, the fetus has a soul and the same rights as a grown human.

The fetus at any given time either has a soul or it doesn't.  There is no intermediate state, no way to change gradually from soul-absent to soul-present, so the change must be instantaneous.

It is normal in quantum mechanics for an object to change gradually from state A to state B, even though there are no intermediate states between A and B.

Take for example, an electron's spin can either point up or down (along whichever axis you choose for the measurement); there is no possible intermediate value it can have.  Yet in the proper conditions can reliably and gradually convert spin-down electrons into the spin-up state, over a predictable length of time. What changes is the probability you will find State A vs State B moves gradually from 0% to 100%.

So my question is, When does the Fetus Acquire the soul and is it an instantaneous event or a continuous event.  Can someone explain this?
At the risk of making enemies from both sides of the war over abortion, I will merely provide my opinion.

There is no way of knowing when God breathes a soul into a fetus. At conception? Somewhere in the Middle?  Biblically we know it happens in the womb at some point because babies in the womb respond to God.

For example:


  When Elizabeth heard Mary's greeting, the baby leaped in her womb, and Elizabeth was filled with the Holy Spirit. (NIV Luke 1:41)


It takes no forced exegesis to naturally assume John the Baptists, 'before he was born' was responding to God, in some way. this implies a living soul.

The prophecy concerning him also predicted it:


  for he will be great before the Lord. And he must not drink wine or strong drink, and he will be filled with the Holy Spirit, even from his mother’s womb. (ESV Luke 1:15)


Here I could not refer to the NIV as to be clear the word for womb is koy-lee'-ah in Greek and must mean womb. Some translations for ease of street-language just say 'from birth' but without any doubt  whatsoever it means 'before birth'.

Therefore it happens sometime in the womb and one can figure out how old the Baptist was and say definitely before then.  However I do not see the at conception argument made in scripture.  It might be? It might not be?

Therefore since we know the soul is in the womb, but do not know one way or another at exactly when, when a woman is thinking about having an abortion, if she believes the Bible, she must assume at a minimum it might be a living soul. But IMPORTANT if a woman has had an abortion and believes it was a sin, by believing in the Bible, her sin is no greater than the sins we have all committed and she can find perfect full forgiveness and cleansing from guilt, by simple faith in Christ apart from any good work she may want to do to atone for it on her own.

Regarding instantaneous or continuous, I would go with instantaneous as God gave Adam a soul instantaneously by breathing into his human body.