Block Universes, Free Will, and Alternative Possibilities

Posted on March 14, 2008
Filed Under Free Will, Philosophy, Science | 7 Comments

OK, I’m pretty rusty on my free will debate. It’s been over a year since I’ve really had the opportunity to read much on free will. So let me add the caveat that this post is partially to help get me back into the flow of things. That caveat in place let me return to the discussion from a few years back on the issues of possibility, block universes and free will.

The point of all this is just to summarize the issues at hand. I’ll have a subsequent post where I delve into the arguments more deeply.


The typical (and most would say necessary) temporal demand of Libertarian free will (LFW) is that the future is completely open. Usually this entails a position of presentism or the belief that only the present is real. This runs into trouble with relativity since arguably it is difficult, if not impossible, to define what the present is if there is no background against which to measure everything. However typically it is seen that quantum mechanics demands a background against which to measure everything. This is seen as one of the big problems of formulating a consistent theory of quantum gravity. Kurt Gödel demonstrated back in 1949 that General Relativity (GR) entails what is called a block universe. Roughly the idea that past, present, and future all exist “at once” in a block. This entails that LFW is false.

reality_block_time1.jpg

Now there are those who tend to reject General Relativity (GR) as normally viewed. Some do this without discussing quantum gravity and just talk about how relativity ends up being an illusion. More interestingly are background dependent theories of quantum gravity like string theory. String theory in theory can be background independent (and some would say should be) but most formulations of string theory are background dependent. This would enable LFW proponents to be compatible with physics, as generally conceived. (We’ll leave alone the controversies of string theory as empirical physics)

The other major theory of quantum gravity is Loop Quantum Gravity (LQG). LQG typically is viewed as background independent. One should note that LQG has had difficulties being fully reconciled to GR. LQG’s biggest proponent, Lee Smolin, has also written extensively on the case for background independence which would render LFW false.

Given that LQG and String Theory haven’t yet been demonstrated to be a working theory of quantum gravity we have to be cautious. I am prone to Lee Smolin’s arguments that any successful theory of quantum gravity must be background independent. I recognize not everyone is so convinced by the physical arguments however.

The question then is the implications for free will.

In a deterministic block universe clearly there can be no Libertarian free will. However if we consider the block universe as a single possibility and acknowledge that, given starting conditions, there are numerous if not infinite possibilities things get more interesting. We then have to distinguish between the block universe that is actualized from the set of possible block universes compatible with the starting conditions. This is roughly akin to a Schrödinger wave equation verses what we see after the collapse of the wave equation. Here leaving aside for now the question of what the collapse means, if anything, philosophically. We are only wanting to separate out the issue of real possibilities from what becomes actualized.

The issue becomes whether one can be said to be free in such a system. I’m quite willing to agree that Libertarian free will probably is not possible in such a scheme. That’s because most LFW proponents suggest that openness must be at the moment of choice. This entails a view of time that demands presentism, as I mentioned. If we allow that time is more akin to an emergent property and that the future is open with our choice being emergent from this set of raw possibilities then is this sufficient?

Now most LFW proponents will say not due to the argument of moral luck. I don’t claim to be an expert on these arguments. (I have ordered Alfred Mele’s Free Will and Luck and when I am able to read it I will almost certainly comment on it. Also see the NDPR review.) It seems to me that for LFW to function it demands either Cartesian dualism or ontological emergence of free will. (i.e. some choosing substance) Nothing now known by science will suffice. If we reject dualism or ontological emergence though is there some more modest form of libertarianism which need not demand such ontological commitments?

Robert Kane has just such a theory and he actually makes the analogy to quantum mechanics that I made. There are several problems with Kane’s approach (see the SEP on Moral Luck I linked to above). The most serious charge is that agents don’t have sufficient control over indeterministic events to allow responsibility. Since responsibility is, to me, the strongest argument for LFW I take this as a strong objection. Kane makes a few arguments for sufficient control but, without summarizing them, I don’t find them persuasive.

What I do find somewhat persuasive is the argument concerning self-forming actions (SFAs). this is the idea that we act from a will formed by earlier choices and actions which were not determined. The idea is that any choice determines what we’d call a character or will that then limits what choices you’d make. That is one event creates new boundary conditions affecting future choices and actions. (One can think of this as possibilities decreasing with time) Yet at any time the future is open.

Now I’m not going to argue here for this position. I think it has some problems but avoids what I see to be the huge problems with determinism as well as the difficult ontological commitments I feel LFW entails (not to mention its problems that I see reconciling with science).

Can this be reconciled with the notion of a block universe as the collapse something like a giant wave function? I think it can.

What we have is a totally open universe. There are then two senses of time. The time as we perceive it and a primordial time of the collapse of the wave function. Put an other way we have an originary time and then normal time. Now it is true that at any particular time t it is already determined what will happen in the future. Yet in an other sense it is indetermined that this would happen. What we have done is argued that indeterminism (or openness) need not have the temporal demand of being indeterminate at a particular time. We merely need that it be indeterminate.

That’s the summary.

The two big problems I foresee LFW advocates having with it is first the acceptance of self-forming actions and second the idea that indeterminism rather than indeterminism at time t is sufficient for freedom. I’ll address those in a second post.

Related posts:

  1. Mormon Free Will Redux
  2. Experimental Philosophy and Free Will Needs a Makeover
  3. Does God Know the Answer of Free Will?
  4. Responsibility, God and Alternative Possibilities
  5. SEP: Free Will
  6. Metaphysics of Agent Libertarian Free Will

Comments

7 Responses to “Block Universes, Free Will, and Alternative Possibilities”

Clark,

Nice summary of the different scientific theories and their implications. When you get to the description of the SFA theory, you lost me mostly.

this is the idea that we act from a will formed by earlier choices and actions which were not determined.

What are these undetermined choices you speak of? Are they free in a libertarian sense, a compatibilist sense, or something else?

Yet in an other sense it is indetermined that this would happen.

What is this other sense? I missed it.

Wrt the “collapse of the wave function”: This term is a description of what happens mathematically. We continue to use it because we have absolutely no idea (at least nothing even heading in the direction of a consensus) what it means in terms of the real world. So, when you start talking about our universe as a collapse of a giant wave function, it sounds to me like very fascinating, but mostly meaningless psuedo-theory.

Jacob, I’ll delve more deeply into that in my next post. I had a few paragraphs on that but the post was too long as it was so I deleted them. Roughly I’m pointing to two different libertarian positions in the literature. One, the one you are probably familiar with, is the agent-libertarianism. This is the idea from our intuitions that free will requires that causes arise in an agent who is ontologically irreducible to other causes or to chance.

The second kind of libertarianism sees freedom in events rather than agents and is quite comfortable seeing agents as emergent out of more fundamental events. (Emergence here meaning it’s more common sense rather than ontological emergence)

There are problems with event-libertarianism. And Blake and probably Geoff won’t accept it in the least. I just thought I’d throw it out.

I hope to do a post in the future on cognitive science and why I think we demand there be irreducible agents in our intuitions. I think these intuitions are more due to how we cognitively think and detect agents in our environment. (This is partially why I am skeptical – although I still think the appeal to responsibility is a powerful argument)

I agree that the collapse of the wave function is what happens mathematically although Von Neumann is who elevated it to a philosophical position. Ultimately though all the collapse consists of is the move from pure possibility to pure actuality.

I don’t think this meaningless pseudotheory though – although I certainly understand why some might say that. The point is that if one denies determinism (which I think physics points to although it doesn’t demand it) then if there is a block universe it must be something like the collapse of the wave function.

I’d also add that this is a question in quantum theory regarding the nature of the collapse (in Von Neumann’s formulation anyway) and what an observation is. Further there’s the obvious question about whether the entire universe is a single entangled entity. Thus demanding that one think about it in those terms. A lot has actually been written here. It also points one back to the kind of ontology that say Spinoza (and to a limited degree Leibniz) suggested. Minus the determinism.

Clark,

I am looking forward to the future installments. I’ll hold off on the free will stuff until I read more of what you have to say.

Ultimately though all the collapse consists of is the move from pure possibility to pure actuality.

I am not sure I can agree with this, maybe you can convince me. Your statement makes it sound as though things exist in pure possibility (whatever that means) until an observer observes them, at which time they have to “collapse” to one of those possibilities. I think it is a bit more complicated than that. In the famous two-slit experiment, you get an interference pattern on the screen even if you fire electrons through the slits one-by-one, so that we are left to wonder how the electron interfers with itself as it goes through the slit(s). So, what is the status of the electron as it travels through the slit(s) in that case? Is it “pure possibility”? It seems that it must have been more than a possibility as it went through the slit(s) or it could not have ended up at the screen eventually. All of this is elementary to you, but I am writing it so you can either correct me or at least understand what I am thinking. We have these concepts like quantum superposition to try to capture the state of the electron when it is not being observed and what I am saying is that it is much more complicated than the term “pure possibility” seems to suggest. Saying that “all the collapse consists of is…” seems a bit too simplistic and the devil is in the details.

Note I’m not taking a stance on how to interpret QM. I find Von Neumann’s interpretation horribly problematic. I’m more just talking about how there are many possibilities that become one actuality. Just as at any moment there are many choices open to us but somehow they become one.

5 Michael Dorfman on March 16th, 2008 1:16 am

Clark: I’m even rustier than you in the whole “free will debate”, because I can’t even seem to find a way for the notion of “free will” to be useful as a discriminator.

Suppose we have two identical universes (let’s say, for the sake of argument, identical to the universe we now inhabit), with identical histories. They are alike in every particular, except that one has free will, one doesn’t. The inhabitants of each believe they have free will, and act identically in both universes.

My question: so what?

It seems to me the obvious rejoinder is whether it is possible to have two identical universes one with free will and one without. I don’t think it is. (Much like I don’t think it is possible to have two identical people: one a zombie and one conscious)

I should add that it appears to me that this is the big difference between ontological emergence and mental dualism. The dualist is committed to the idea that the physical universe can be identical in two possible worlds that are different whereas the ontological emergentist is committed to them being the same. (Beyond that it seems to me that there is no difference between the positions)

I think Mele’s argument ends up being similar to Michael’s. There’s still the question of whether it’s possible to have two universes identical except one has free will and the other doesn’t. So Mele’s is a tad more complex since it raises the question of luck vs. free will.

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