Tuesday, April 16, 2013

Christian compatibilist free will?

Something interesting came up in the comments on my post about the free will defense against the problem of evil, and I wish to recap it.

First, commenter James brought up the argument that God's omniscience contradicts free will.  Commenter Slightlymetaphysical brushed off the argument.  I would brush it off too.  Pshhh, why should omniscience contradict free will?  Just because you know what someone chose doesn't mean that they didn't choose it.

Of course, the reason I would brush it off is because I'm very used to compatibilist free will.  That is, I believe free will is compatible with determinism.  An act of free will is just something that is arises directly from a set of conscious cognitive processes.  Even if those cognitive processes are deterministic, that doesn't mean our decisions weren't caused by them.

But there are also incompatibilist conceptions of free will.  For example, commenter Larry offered the following definition (without necessarily endorsing it):
1. Assume there is some state of the world at time t.
2. Agent A makes decision D at time t+1.
3. We "roll back" the world precisely to its state at time t
4. Agent A has "free will" if and only if she could make a different decision, D', at time t+1.
Clearly, this kind of "free will" is incompatible with determinism, because in a deterministic world, there is only one possible outcome, given initial conditions.

As a result of the comment discussion, I realized that Christians are implicitly taking a compatibilist view of free will.  As long as they accept the following premises, they must accept the conclusion:
Premise 1: Free will exists.
Premise 2: An omniscient being exists.
Premise 3: The existence of omniscience implies determinism.
Conclusion: Free will is compatible with determinism.
This is very interesting, because it is not in accordance with other Christian views on free will.  And in particular, it's not in accordance with the free will defense against the problem of evil.

The Christian* view on free will is that it is the ability to turn against God.  Eve had the ability to eat that apple (or pomegranate or what have you), and the ability to choose not to.  For reasons infathomable, this kind of free will is so desirable to God that it is worth the evil that proceeds from it.  On the other hand, if we believe in compatibilist free will, then God can have his cake and eat it too.  That is, people can have the ability to choose evil, even when it is predetermined that they will not exercise this ability.

*More accurately, a Christian view, which is not necessarily universal among Christians.

The problem of evil is the question, "Why does God allow evil?"  The free will defense is, "Evil is a necessary consequence of free will."  My proposed counter is, "But free will is compatible with a world where no one chooses evil."

Of course, this is one of those purely philosophical arguments, and we all know how unpersuasive those are.  Here are a couple responses:
  • Omniscience does not imply determinism. An omniscient being could simply be aware of all possibilities and their outcomes, without knowing which possibilities will come to pass.  One could counter that this kind of omniscience is hardly a proper omniscience at all.  But I for one would still be very impressed by such a being, whether it's proper omniscience or not.
  • It is not free will itself that God finds so desirable.  Rather, God desires that people have the ability to go against him, and that they actually exercise this ability.  God's desire does apply to heaven, where he is basically okay with the fact that everyone is choosing good.  God sure has some strange desires, but the truth can be strange.


James said...

Interesting thoughts. At first, it feels like determinism. The crux of Christianity is that God sent Jesus to die for humanity's sins. But what if Pilot had chosen to pardon and release Jesus instead?

Of course God knew he wouldn't do that, but did he have the free will to make that choice, thereby ruining God's plan? It seems the Bible is full of examples of God intervening and preventing people from making choices. One example is how "God hardened Pharaoh's heart" so he wouldn't choose to free the Israelite slaves until God proved his point.

So basically, we have free will yet we could not have made choices other than the ones we made? I guess "Man can do what he wills but he cannot will what he wills."

James said...

Another through:

Let's pretend God created the universe like someone who writes and directs a movie. Every human is an actor in the movie. We have free will but we can only choose to read the lines given to us. We don't have the script beforehand, so we just read them as we go. God is sitting in his personal movie theater watching the finished production. As the writer and director, he knows every scene and line will be just as he had chosen.

Does this work with the compatibilist view?

miller said...

"Does this work with he compatibilist view?"

There isn't enough information in your example. It is possible to believe in compatibilism while also believing that free will does not exist. If you're interested in compatibilism, there's lots of stuff online that's better than anything I could write.

drransom said...

I wonder what theory of modality is being used in part 4 of Larry's definition. If we use possible worlds semantics, consider a possible world where the state of the world is identical but the laws of nature are different, so that A makes a different decision at t + 1. That would mean that everything has free will, including inanimate objects. If the "rolling back" requires that the laws of nature remain the same at time t, consider a possible world where the laws of nature change between t and t+1. Again, Larry's definition produces the conclusion that everything has free will.

Or, for another alternative, the many-worlds interpretation of quantum mechanics, where the many worlds branch off in a deterministic way (e.g. one world branches off spin up, and another branches off spin down). Is that non-deterministic? The identity and number of worlds that branch off is deterministic, even though the same initial conditions produce multiple worlds. That would seem to fit Larry's definition, and would also result in everything having free will.

I think Larry must be using a different modality theory, but I'm not sure what it is.

miller said...

I believe that Larry simply didn't want to spend the time developing a fuller definition of free will when all he needed was a rhetorical example of an incompatibilist definition.

Larry Hamelin said...

You are correct, miller. Also, it's not *my* definition of "free will," it's Coyne's.

I'm a noncognitivist, at least on alternate Wednesdays. I don't think the term "free will" actually means anything at all.

tom.harrigan said...

The reason omniscience contradicts freedom is the same reason randomness and freedom are different. It may appear subtle, but randomness can be calculated ahead of time. Subsequent actions will then appear random, and will in fact be random, but they are determined. So, randomness (omniscience) and determinism are the same thing. Freedom and indeterminism are something else. Fortunately the debate is over, as we know how nature behaves.

The experiment you outline is difficult to perform, however analagous experiments have been performed many times, if you accept that the "roll-back" of time is equivalent to the repeat of an experiment with identical particles. A particularly clear exposition of the implications of such experiments is to be found in Kochen and Conway's "Free Will Theorem".

We have known since the 1920's that at a fundamental level nature is indeterministic. In fact didn't Max Born get the Nobel Prize for that insight? We also know that this indeterminism can affect the state of macroscopic objects, otherwise we couldn't do experiments on particles.