Saturday, February 23, 2019

Problems with Determinism

It's a common assumption among naturalistic materialists that, despite the inescapable sense that we're often able to make genuine choices, this sense is an illusion. In a completely material world governed by physical laws, there's no room for the sort of freedom we normally, and naively, think we have.

Given this view, our every choice is the product of all of the influences that have acted upon us from the time of our conception and at any given moment there's really only one possible future. Let's call this view volitional determinism. According to volitional determinism free will is an illusion, as is your conviction that you freely chose to read this post.

Volitional determinism is a derivative of what might be called broad or universal determinism. This is the idea that everything that happens in nature, in the physical universe, is the inevitable consequence of prior causes such that, given the cause, or series of causes, the consequence must necessarily obtain.

Since our choices are events that occur in the universe our choices are necessarily determined.

The argument can be summarized like this:
  1. Every event in the physical universe is determined by antecedent physical causes.
  2. Our choices are events in the physical universe.
  3. Therefore, our choices are determined by antecedent causes.
The argument is valid, to be sure, but both of its premises are open to challenge. In fact, the first premise is almost certainly false, and the second one might well be false. But, if either premise is false then the argument falls apart.

As neuroscientist Michael Egnor explains in a brief article at Mind Matters the first premise is indeed false since physicists have shown beyond any reasonable doubt that the universe is not entirely deterministic.

Egnor writes:
In a previous post, I argued that if determinism is true, we cannot have free will. That is, if everything we do is determined by the laws of physics and chemistry, there is no room for genuine freedom. In that respect, I am an “incompatibilist”—I don’t believe that free will is compatible with determinism.

What do I mean by determinism? Determinism, in the scientific sense intended here, is the view that for every moment in time, the state of the universe is completely determined by the state that immediately precedes it. If you knew all of the details of the universe — the location and state of every particle — at any given moment, you could know with certainty what comes next.

Determinism is more or less the view that nature is a machine. If we know the position of the gears, we can know the future with certainty.

The question that naturally follows is this: Is determinism true? If so, free will is impossible in principle. If not, free will is possible.

In 1964, Irish physicist John Bell (1928–1990) published a paper titled “On the Einstein Podolsky Rosen Paradox”. In it, he observed that there is a way to test determinism at the quantum level by measuring the ratio of quantum states of particles emitted by radioactive decay.

Bell’s experiment has now been done many times, and the answer is unequivocal: determinism at the quantum level is not true. Nature is not deterministic.

The experiments showed that every quantum process entails some degree of “indeterminism”; that is, there are predictable probabilities but there is never certainty. If we knew the exact state of the universe at any given moment, we could still never know with certainty what would happen next.

Determinism in nature has been shown, scientifically, to be false. There is no real debate about this among physicists.
The second premise is also questionable because unless one has ruled out apriori the possibility that human beings possess an immaterial mind there's no reason to think that our choices must be physical events occurring in the physical universe.

If immaterial minds do exist then it's quite possible that our choices occur in that faculty, at least in part, and are therefore not subject to the physical laws and forces that govern the material world.

If naturalistic materialism is true then determinism is probably true, but if naturalism is false determinism could well be false.

What one thinks about determinism and free will all depends upon whether one has embraced a naturalistic worldview or not.