A thought experiment on free will

March 20, 2008

in Science, Writing

Rusty fence and snow

Consider the following: what we know about physics and chemistry suggests that matter and energy interact on the basis of two things - physical laws and random chance. The fact that iron oxidizes is the result of physical characteristics of energy and matter that we understand well. Similarly, our understanding of the random elements in quantum mechanics is critical to a number of optical and electronic technologies. Acknowledging that we don’t fully understand either the laws of physics or the processes of randomness, it seems plausible to say that those two factors account for all the physical interactions in the universe.

If this is true, we can imagine a hypothetical computer with the capacity to store information on the nature, position, and trajectory of every particle in a human body, as well as all the types of energy acting on them. This model would allow us to project the behaviour of that collection of molecules in the face of any stimulus, at least on the basis of a range of outcomes as determined by the random elements in physical laws. Our model human could thus be exposed to any kind of prompt - from being attacked by another simulated human to being tempted by some unguarded treasure to being betrayed by a loved one - and a range of responses could be projected, with probabilities attributed.

Now, if human beings really do consist of particles and energy governed in the manner described, the behaviour of the computer model would be in no sense different from that of an actual person. The trouble here, of course, is that the model person cannot be said to have any free will. It is just a complex machine that responds to inputs in relatively predictable ways. Where outputs are not predictable, it is because of random chance. Our model person is like a computer game where the enemy you encounter is determined by a random number generator; while the outcome for any input is not entirely predictable, the system is nonetheless completely devoid of ‘will’ in the sense that we generally understand it.

How can free will be fit into a materialist model? Is free will something that exists outside of the laws of physics? Or is there some mechanism through which a macro-level entity like a person can be said to affect the particle level interactions that define them fundamentally?

Regardless of the answer, the thought experiment raises serious questions about whether we are responsible for our actions.

[Update: 2:06pm] Tristan wrote a post in response to this.

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{ 19 comments… read them below or add one }

Milan 03.19.08 at 11:24 am
Milan 03.20.08 at 10:45 am

This post is partly in response to this discussion.

Tristan 03.20.08 at 12:39 pm

Milan,

You are simply wrong in thinking this is anything new or special about 20th century science. It follows logically from assuming everything in the universe moves according to a single set of physical laws, that humans move according to that set and are unfree. This is why Kant had to come up with his strange solution of 2 ways of considering the human being - as an object of science and as an object of freedom which obeys a different law.

Basically, the fundamental mistake you are making is expressed here: “if human beings really do consist of particles and energy governed in the manner described”

What is this “really are”. Do you mean, they are this way, in the exclusion of other ways? Are you an eliminative materialist, in other words, any phenomena that supervene onf these interactions, like say, anger, where you can’t tell a meaningful story about the thing (anger) in terms of matter and energy, is simply a mistaken concept which we need to get rid of? So, “anger” exists if and only if it is a manner of the interaction of energy and matter that can be described as those interactions? That seems wrong, any idiot knows anger exists, and it doesn’t matter if the neuro scientists can find it or not. Any philosopher who denies the existence of these things is rediculed.

But for some reason, if instead of “anger” you substitute” freedom” everyone freaks out and says “oh we arn’t responsible for our actions”. If we take science seriously in your sense, not only can we not affirm freedom, we can’t affirm states, or the law, or schools, none of these phenomena can be described meaningfully as the interaction of energy and matter - you will never find a law. Looked at as energy and matter, the law will appear to be a totally incomprehensible supervenient phenomenon, a “mistake”, like folk psychology.

The mistake is moving from “the current model we have of the world is the interaction of matter and energy across space-time”, to, “the world really is this model”. This is Platonism - you’re assuming the world is in itself a differentiation according to permanently enduring laws. The mistake is to think that Empiricism automatically gets you away from Platonism - empiricism is a method, it doesn’t imply a metaphysical position. If you assume the world is in itself the kind of thing that works like a model, then you believe in Platonic forms.

You do believe in Platonic forms. They are called “energy and matter”. It’s an indefensible position - Platonism is wrong, for reasons that are so obvious I can’t begin to discuss them. So your thought experiment doesn’t actaully say anything meaningful at all about freedom, although it does express quite clearly the platonic skeletons empiricism tries to hide in the closet.

Milan 03.20.08 at 12:48 pm

You are simply wrong in thinking this is anything new or special about 20th century science. It follows logically from assuming everything in the universe moves according to a single set of physical laws, that humans move according to that set and are unfree.

I made no such claim. The argument above could have been made just as well on the basis of less advanced scientific understanding. All that it requires is acceptance that universal laws and random chance are the only determinants of physical outcomes.

Milan 03.20.08 at 12:52 pm

In general, I think you are placing far too much emphasis on how we describe things. In the end, that doesn’t matter hugely. It has as much effect on the physical basis of the world as changing the category we file Pluto under (from ‘planet’ to ‘dwarf planet’) does upon the physical characteristics of the object itself.

You can’t just wave a rhetorical hand and reject the argument above as one kind of thinking. You need to argue where within a material world free will could reside, that there is no free will, or that the world is not material.

Milan 03.20.08 at 2:37 pm

Tristan,

If we actually had a computerized Tristan model that you could observe behaving as you would, could you still consider yourself free?

Mark 03.20.08 at 5:20 pm

I was thinking about this last week while doing my ironing…

Let me begin by stating the obvious. When it comes to conscious agents like human beings, there are definitely things that are not currently understood. There is essentially no scientific understanding of consciousness and qualia, for example. Here be dragons.

Given that this isn’t presently a scientific question, we can happily disagree about it all day long - as indeed philosophers have been doing at least since Hobbes. I think the best way to make progress towards real understanding is to do more neuroscience and build better robots.

For what it’s worth though, I tend to believe that Milan’s “replica” is possible. The traditional view that “a human being is an independent point of departure”, while initially obvious, becomes much less obvious on reflection. At what point in your thinking do you do the “choosing”?

For example, say that you want to become president of the United States. Given your current knowledge, you can consider all actions open to you and score each action based on how likely it is to lead to your goal. You then follow the course of action with the highest score (moderated of course by the effect this has on all the other things that you might want). The only freedom you have here is the freedom to choose badly. Choosing any action other than the one with the highest score would be acting contrary to you will (i.e. to become president).

So, if free will exists, it must exist earlier in the process - in choosing what to want. Yet, I think most people’s intuition here is that we don’t choose what to want. Our wants are the part of us most clearly tied to our biology - things like eating, sleeping, mating. Of course, humans have more abstract wants - the desire to be loved, the desire to be dutiful; I think these are ultimately biological too.

How this affects things like legal responsibility and notions of morality is another huge question. I think (perhaps surprisingly) it doesn’t actually change things too much, but that is another mammoth discussion, and this comment is long enough already.
In fact, I think that whether or not we have free will changes remarkably little. We are all acting towards our goals. The idea that the things we want are innate or determined by our experience in ways that we do not choose is almost a commonplace. It takes nothing away from that fact that we experience joy and terror, love and hate. I have no doubt that these are real, and they certainly pose a challenge to scientific understanding. It may even turn out that the gap in our scientific understanding that permits conscious experience also permits free will, but I suspect that it does not, and I think we as a species need to be ready for the possibility.

Milan 03.20.08 at 5:26 pm

My personal response to this question is pragmatic, and based on two binaries:

1) Either we have free will or we do not

2) Either we choose to act as though we have free will or we do not.

If we lack free will, then we have no choice whatsoever in any matter and all morality is moot.

If we possess free will, we want to behave as though we do. If we get it wrong and act as though we don’t (it’s not clear how we actually could), we would be making a mistake. If we actually have any freedom to choose, choosing to believe in free will is necessarily correct.

. 03.20.08 at 5:36 pm
Mark 03.20.08 at 7:38 pm

Milan - A rather sensible position!

tristan 03.20.08 at 11:26 pm

You are right, it doesn’t matter hugely how we describe the world. And then you say where in a material world could free will reside. Well, it doesn’t matter, because the material world is the described world.

mek 03.21.08 at 5:36 am

Well, this is quite the mountain you’ve decided to tackle in this post. I just want to quickly dismiss materialism altogether, and then follow up with an observed contradiction in post-materialist theory (Chalmers, etc).

Setting aside the subject of free will for the moment, your example of the “human replica” rather directly mirrors Chalmers’ zombie; the idea that a whole physical description of a human being could be made, but in his example, this description lacks something inherent to the human experience; the experience of being, as Tristan noted, qualia. We can easily imagine an experience-less individual; all we need to do is look at a person other than ourselves. This immediately leaves us with a number of problems.

A purely physical description of a human being, or more importantly, a group of human beings, leaves us without a fundamental, and essential, piece of information: how is this described reality experienced? Which one of the humans is me, and which ones are not-me? This bit of information seems scientifically trivial, but philosophically, and self-evidenty, it is of ultimate importance. This is the indexical fact, something seemingly un-physical but of absolutely non-trivial importance: given a full description of all physical reality, how can one evaluate the truth value of the statement “I am happy” without knowledge of the indexical fact? Such a statement could never have truth-value of any kind if we were dealing with “zombies” or “human simulations”.

Things get really messy when you consider that the indexical fact, simply having been conceived of and discussed by us, has now had physical consequences on reality: such as the words now appearing in your web browser. If the indexical fact is non-physical, as our materialist accounts of reality seem to indicate it is, how can it have physical consequences?

In short, this is a big philosophical mess. Materialism, as we once knew it, is dead.

Tristan 03.21.08 at 11:08 am

Mek,

I just had the fairly unpleasant realization that if we had met in a regular metaphysics class its quite unlikely we would have become friends. Whose Chalmers? Indexicals? What about transcendence! Corrigibility!

I still hold, that it isn’t the task of philosophy to prove that we’re free, but rather show what it means when you say “you are free”. The problem with the “is there freedom” question is it leaves “what is freedom” completely uninterrogated, kind of like how separatists leave aside their real differences on social issues to pursue independence.

Mike 03.21.08 at 7:20 pm

I vacillate between being completely deterministic in my views on free will and believing in some sort of chaotic principle that is also not free will, but not quite randomness, either.

I think that recursion is what makes the free will illusion so pervasive, and so strong — the actor acting on itself over and over again.

But I am done, pretty much, arguing over free will. Years ago, I would’ve written, depending on my mood, what you wrote, or what Tristan posited — since then, though I’ve realize the only tenable position is to act as if free will exists, even if it does not.

Milan 03.22.08 at 12:10 am

The Trap on the Google Video

Adam Curtis’ “The Trap” is a documentary broadcast in 2007 on BBC exploring the development of modern concepts of individual freedom.

James 03.25.08 at 8:44 am

Hi Milan. No doubt you know this, but there’s a huge debate in contemporary (and not-so-contemporary) philosophy about (1) whether there are notions of free will that are “compatibilist” - that is, consistent with determinism; and (2) whether there are notions of moral responsibility that are compatibilist; and (3) whether moral responsibility requires free will.

For a way into the literature, try:
http://plato.stanford.edu/entries/compatibilism/
http://plato.stanford.edu/entries/incompatibilism-argum ents/

Incidentally, there are also questions about whether *indeterminism* would be any better. Some people (e.g. Galen Strawson) think not only that free will is inconsistent with determinism, but also that it’s inconsistent with indeterminism. According to this view, we’re no more free in irreducibly chancy worlds than we are in deterministic worlds. If this is right, debates about whether determinism is actually true in this world are moot, because free will is impossible: it doesn’t exist in any possible world, deterministic or not.

. 04.06.08 at 8:43 pm

What is it like to be a bat?
-Thomas Nagel

[From The Philosophical Review LXXXIII, 4 (October 1974): 435-50.]

Consciousness is what makes the mind-body problem really intractable. Perhaps that is why current discussions of the problem give it little attention or get it obviously wrong. The recent wave of reductionist euphoria has produced several analyses of mental phenomena and mental concepts designed to explain the possibility of some variety of materialism, psychophysical identification, or reduction.1 But the problems dealt with are those common to this type of reduction and other types, and what makes the mind-body problem unique, and unlike the water-H2O problem or the Turing machine-IBM machine problem or the lightning-electrical discharge problem or the gene-DNA problem or the oak tree-hydrocarbon problem, is ignored…

. 04.15.08 at 11:19 am

The ethics of brain science
Open your mind

May 23rd 2002
From The Economist print edition

Screening, privacy and enhancement are all important issues, to be sure. For many critics, though, they are side-shows. The really uncomfortable questions raised by brain science are those that go to the heart of what it is to be human. Or, more specifically, what philosophers and theologians have claimed is the heart of what it is to be human.

In the West, at least, that defining quality is the concept of “free will”. Although some philosophers see free will as an illusion that helps people to interact with one another, others think it is genuine—in other words, that an individual faced with a particular set of circumstances really could take any one of a range of actions. That, however, sits uncomfortably with the idea that mental decisions are purely the consequence of electrochemical interactions in the brain, since the output of such interactions might be expected to be an inevitable consequence of the input. It also sits uncomfortably with the separate, but parallel, argument that correct moral choices are the result of a sort of biological decision-making programme, shaped by evolution, rather than being arrived at by abstract reasoning.

. 08.16.08 at 5:14 pm

Do Subatomic Particles Have Free Will?

By kdawson on painting-fences-white-very-quickly

An anonymous reader sends in a Science News article that begins: “Human free will might seem like the squishiest of philosophical subjects, way beyond the realm of mathematical demonstration. But two highly regarded Princeton mathematicians, John Conway and Simon Kochen, claim to have proven that if humans have even the tiniest amount of free will, then atoms themselves must also behave unpredictably” Standard interpretations of quantum mechanics, of course, embrace unpredictability. But many physicists aren’t comfortable with that, and are working to develop deterministic interpretations of quantum mechanics. Conway and Kochen’s proof argues that these efforts will be fruitless — unless one is willing to give up human free will, in a very strong sense. The article quotes Conway: “We can really prove that there’s no algorithm, no way that the particle can give an answer that is unique and can be specified ahead of time. I’m still amazed that we can actually manage to prove that.”

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