Monday, December 11, 2006

Laws of Nature and Free Will

By Mogens Michaelsen

An article by Behind My Screen: "There is no Free Will: A Secular Argument" inspired me to write a little about the relation between the laws of nature and free will.

Many people think, that since the universe is governed by natural laws, it must necessarily be determined in a way that excludes free will.

The first argument against this, is the fact, that according to science the world we live in is not fully pre-determined in the sense that it is possible to calculate the present state if you knew everything about a state in the past. According to the so-called Copenhagen interpretation of Quantum Mechanics this is due to the "Uncertainty Principle" which makes it impossible to measure both the exact location and the impulse of an electron at the same time. I will not go further into this here, but the implication of it is, that there is an element of randomness in the world/universe. Because Albert Einstein was opposed to this theory he said something like: "I don't think God plays dice". This is often used to argue, that Einstein believed in a personal "God" - which is actually not the case. It is more correct to view it as a metaphor, referring only to the question of randomness.

If we look at another interpretation of Quantum Mechanics called MWI (Many Worlds Interpretation) it is a little more complicated. Here you have to make a distinction between a "world" and the universe as a whole. The reality which most people call "the universe" is only a single world in this theory, and this is only a part of the universe - a part of the universe in which we exist as observers. In contrast to the Copenhagen interpretation, MWI claims that there is no real randomness, because all the possibilities are actually realized, but any observer in our world will observe that he or she is still living in "the world". Since the state of this world is not fully predictable, there appears to be some randomness in the chain of events. The interesting question then is, if it is correct to say, that this apparent randomness is simply an illusion? Personally I would say that it is relative to the observer. If it was possible for an observer to observe the whole universe, there is no randomness. But if you are an observer in a "world" (which human observers normally are!) there actually is randomness in this world - objectively, that is.

My explanation of the interpretations of Quantum Mechanics is very far from complete, but that is actually not my intention here. My intention is to explain, that no matter which interpretation of Quantum Mechanics is used, the existence of a given person in the world is not pre-determined, not even if the universe is 100 pct. deterministic!

The implication of this is, that your own existence as a living human being, is not a necessity, meaning that it is not simply a necessary consequence of the laws of nature. To be, or not to be, that is the question...

Where do all this connect to the question of free will?

Well, it doesn't prove that we have a free will, but it certainly doesn't exclude it either. Most people will probably say, that if everything is pre-determined in the simple sense of the word, you can hardly give any meaning to the concept of "free will". Free will would at best be an illusion, or something like that.

Now I will try to view the laws of nature from a different perspective. And I will do that by a simple example:

1) Imagine a person holding a small object in his hand, e.g. a cigarette lighter.

2) Ask this person to decide whether to drop the lighter or not. And tell him he is free to make the decision himself.

3) Tell the person, that if he drops the lighter within a minute, he will get 10 dollars. If he doesn't drop the lighter within a minute, it will be chosen by random, whether he will get 100 dollars, or no money at all.

Now, what you can "predict" is, that the person will perform some thinking before deciding whether to drop the lighter or not. But can you predict much else than that? Some might say, that his decision will depend on how much he needs how much money, but do you know that for sure? I don't think so - it is also possible that he choose to do the opposite of what he thinks the instructor expects, in order to demonstrate that he has a free will.

Does that mean, that you cannot predict much else than that?

Actually there is another important thing you can predict: If he choose to drop the lighter, you will see the lighter move towards the floor, due to gravity! Or to be more correct: If you see the lighter move towards the floor, you know that he must have decided to drop it. You also know, that the lighter would move towards the floor with an acceleration of 9.8 m/sec^2, if it was not for air-resistance. Of course the exact value of the lighter's acceleration is not relevant, but the fact that there is a natural law - the law of gravity - governing this movement certainly is. If the lighter could just as well move in a random direction with a random speed, the person cannot choose to drop the lighter, since he is not able to predict the movement, and since "dropping" is defined as involving a movement towards the floor. In short: he can only choose to drop the lighter if the laws of nature is like they actually are.

Conclusion: The laws of nature does not contradict free choices. The laws of nature is a necessary precondition for free choice.

Newsvine: Laws of Nature and Free Will
Newsvine: There is no Free Will: A Secular Argument