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Molly Pieri's picture

Free Will in Quantum Physics

Last Tuesday, we briefly readdressed the issue of a self outside of/ independent from the body. I just thought I'd share an idea with the class that I think allows for a self outside of the body, while still basing all behavior off of chemical reactions...

A few years ago, I read An Elegant Universe by Brian Greene. In this book, he talks about the implications that concepts from physics have for our daily lives and our conceptions of the self. After reading this book (which, by the way, I really liked, and highly recommend to anyone interested in this sort of thing...) I find that I like Brian Greene's way of reconciling the free-will vs. bag-o-chemicals debate. Or, at least, I like my interpretation of what he has to say. I'm not sure that he would be entirely appreciative of me labeling this rant in this name. So, with that said, my retelling of Mr. Greene's solution:

The system we call Newtonian Mechanics holds that if you know the location, mass, velocity, acceleration, spin etc... of every particle every where (let's say we have a giant super computer that can actually do this) then you could calculate precisely, with 100% certainty, every future event.

Quantum mechanics, on the other hand, explains that there is no way to know with 100% certainty the location, mass, velocity, acceleration, spin etc of every particle at the same time. You can know one of these things to 100% accuracy, but in doing so, must sacrifice the extent of your knowledge of another one of the particle's aspects. To get around this, we can rather determine the probability that a certain particle will be moving at a certain velocity with a certain acceleration thought a certain point at a certain time. Under this system, it is impossible to predict the future- you can only determine the probability that any give future event will occur. (Schodinger had a story about a cat which demonstrated this quite nicely, if a touch inhumanely. He explains that if you put a cat in a box with some radioactive material and the cat's life depends on the decomposition of this material, you can't know whether the cat is alive or dead before you open the box up the check, because really, the cat is both alive and dead at the same time, until you look and see which it is... he's basically using the cat's life as a metaphor for a subatomic particle to explain the paradox that is quantum physics.)

Any way, cats aside, Newtonian mechanics work pretty well for most things we encounter in life- thanks to Newton, we are able to drive our cars, catch footballs, and jump on pogo sticks, all sorts of things. But this system of physical principles doesn't really work for very very small objects, like electrons. (Or for things which are very very dense, like black holes, or things traveling very very fast, like light, but we aren't really concerned about this right now...) For the activities of subatomic particles (and the like) we must turn to quantum mechanics to get our answers.

Therefor we can conclude that, if all human behavior is the product of chemical reactions (that is, the behavior of subatomic particles, namely, electrons) then the more appropriate system with which to describe this behavior would be quantum mechanics. Using this system, we can only determine the probability that we will act in a certain way at a certain time in the future. This, I think, allows for the idea that even though we are just "salt running in and out of tubes" there is still the chance for free will to exist within us.


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