Tuesday, June 29, 2010

Why Theistic Libertarians Should Believe In Future Facts and Backward Causation

...at least if they believe in infallible divine foreknowledge.

I'm not aware of any empirical research to back this up, but my strong anecdotal impression is that theistic philosophers who take an interest in free will are, in the vast majority of cases, libertarians. Now, libertarians come in all sorts of different flavors, but the relevant features for our purposes right now are just:

(a) a belief that humans do indeed have free will &
(b) incompatibilism about free will and determinism

Now, historically, many smart people have worried about the compatibility of divine foreknowledge with free will, but (at least given the positions formed in response to the question of *determinism* and free will) it's not clear what the big deal is. As long as you believe in future facts, there's no problem with (a) believing that there are facts about what undetermined radically self-caused free decisions people will make in the future, and that(b) God, being omniscient, knows all such facts, without anything about that knowledge undermining the libertarian picture.

One problem, though, is that this would seem to commit anyone who believed both (a) and (b) to a form of backward causation. Free decisions I will make in 2020 are causing God's knowledge of them in 2010. Some people view the thought of any sort of causal sequence where the effect precedes the cause with extreme discomfort. Can theistic libertarians, then, make sense of things *without* postulating a process of backward causation whereby future facts cause present divine mental states?

Well, here are a couple of easy ways out, that allow the theistic libertarian to believe that God's knowledge includes knowledge of precisely which free decisions we'll make in 2020:

(i) Deny that this is *foreknowledge*, or
(ii) Deny that it is infallible

Some theologians argue that God is, in some sense, "outside of time." It's controversial whether there's even any coherent way to make sense of this idea, and I'm pretty skeptical, but that's a complicated and interesting subject for another time. For the moment, just note that it amounts to (i). God's atemporal knowledge of all of time wouldn't be foreknowledge, so this amounts to giving up on the project of making sense of divine foreknowledge without determinism or backward causation.

More creatively, one could argue that, even in an indeterministic universe, certain sorts of evidence about the present give one a very high degree of justification for one's beliefs about what people will do in the future, enough so that (if they are true) those beliefs count as knowledge. Surely, all evidentially-based human knowledge of the future is of this kind, whether or not we live in an indeterministic universe. After all, even in a deterministic universe, there's always the possibility that we're misinterpreting the evidence. Despite this, surely we at least sometimes know at least some things about what will happen in the future. Surely, in an indeterministic universe, God, with His complete and flawless knowledge of every aspect of the present, would have extremely well-justified beliefs about what will happen in the future, beliefs that, by parity of reasoning, would count as knowledge if those beliefs were true. So far, so good, but given indeterminism, surely some of God's beliefs about the future would be *false*, right?

Well....

If a clock is broken at 8 O'clock, it's possible that every time anyone ever happens to look at it, it will be either 8 AM or 8 PM. If a coin is fair, it is nevertheless just barely possible that it happens to come up heads every time it happens to be flipped. Perhaps, through a massive, bizarre coincidence, God's fallible knowledge of the future never happens to fail. To claim that this is how God has an entirely accurate and complete knowledge of the future would be massively ad hoc, but it's just barely in the logical space of possibilities.

Still, this doesn't seem to be what people typically mean by divine foreknowledge. It seems to me that, built into ordinary usage of the concept, is the notion that God's foreknowledge is infallible. It's not just that God's beliefs have always and will always luckily happen to be true, but that there's a deep sense in which it would impossible for God to make a mistake.

So, how about reconciling infallible divine foreknowledge with libertarianism without backward causation?

Many theists seem to think this can be done with "middle knowledge." God knows what you would do under certain circumstances, and God knows which circumstances will arise, therefore even without (a) determinism, or (b) God just having direct access to future facts, it is still the case that (c) God knows absolutely everything that will happen in the future.

Now, first notice that we're attributing to God not just knowledge of the "counterfactuals of freedom" of people who already exist, but also of people who will come into existence in the future. Thus, without God having direct epistemic access to the future, God knows the exact details of every free decision that will ever be made by every person who will come into existence 10,000 years in the future.

Now, for the theistic compatibilist (who accepts determinism), that's no problem--given determinism, everything about the character of future people, what kind of decisions they will make, etc., is a function of genetics, environment, etc., and is ultimately all built into the present physical state of the universe. If God knows everything about the present and everything about the laws of nature, He can extrapolate the total state of the universe 10,000 years in the future, including (given a compatibilist understanding of freedom) every free decision made by those future people.

But....for a theistic libertarian, just how does this work? For the sake of simplicity, let's stick with the (presently non-existent) children of present people. Given His knowledge of present-tense facts about you and the person who you will one day have kids with, combined with His knowledge of facts about which external circumstances will arise, God can have foreknowledge of which people will come into existence. How, however, does He know (without direct access to future facts) what decisions those (presently non-existent) children will make under various circumstances, unless that's simply a function of their genetics and environment? Given a view of free will that says that a decision can't be simultaneously determined and free, middle knowledge of presently non-existent people would seem to obviously, trivially rule out free will.

It gets worse. Even for God to have short-term infallible foreknowledge of the future actions of presently existing people without having direct access to future facts, determinism creeps back in. After all, if, given present facts about the agent's character, unavoidable external circumstances, etc., their eventual decision is unavoidable--which is what it amounts to to say that a being with infallible knowledge of all those present facts would therefore have infallible extrapolative knowledge of their future decisions--then those decisions are causally determined. The agent can't do otherwise in the sense of "can do otherwise" that differentiates libertarians from compatibilists.

Of course, there are "softer" versions of libertarianism whereby it's OK for most decisions to be causally determined given previous facts about character, etc., provided that certain key "character-forming decisions" are radically free from deterministic chains of cause-and-effect. Even those kinds of moderate libertarian views won't help here, though, given that God would not have had even short-term infallible foreknowledge of those key character-forming decisions.

One way or the other, without backward causation (i.e. direct divine access to future facts), either you have to give up on across-the-board infallible divine foreknowledge or you have to give up on indeterminism. It looks to me like anyone who wants to combine classical theism (complete with infallible divine foreknowledge) with a libertarian view of free will would be well-advised to get over any squeamishness they might have about future facts and backward causation.

Thoughts?

3 comments:

chaospet said...

Correct on all points, sir.

observationalist said...

I am not much for labels simply because labels are limiting. When thinking about god, it is much better to know that we do not know. This is the best way to live without coming to any conclusions about the design of the universe. We are blotches on a big, dirty ball; we are the ball.

Ben said...

If I claimed to have an invisible elf tap-dancing on the palm of my hand while singing show tunes at a frequency that humans don't know how to detect, would you take the whole 'wisely admit that we know that we don't know' route, or would you reject my claim on the obvious grounds that I've given you no evidence, that I'm going to have to make all sorts of ad hoc moves to protect the elf theory from refutation, and that, y'know, the theory that there is no elf has an obvious advantage in terms of ontological simplicity? If the latter, what's the distinction between that case and the question of the existence of God?

(Or are you assuming some sort of blurry-water-color version of theism and rejecting the need to tell a coherent story about the details by talking about knowing that we can't know? Your aversion to 'labels' makes it hard to tell.)