Subscribe to Computing Intelligence

Wednesday, October 21, 2009

Free Will Revisited

Just over a year ago, at the request of Cornucrapia, I made a post discussing my outlook on the concept of free will. Since free will seems to be one of those topics that refuses to keep its ugly head down, Robert sent me an email mentioning that it had come up at the new atheist group at the University of North Carolina at Greensboro. While I directed him to have a look at my original free will post, I thought it might be worth rattling off some more musings on the matter. The subject of free will, after all, is ostensibly a question about the function of the brain, so one would think that I might have something sage-like to say on the matter.

As I mentioned in my original post, I am actually not a fan of the topic. My dislike is not based on finding the topic itself dull, but rather because it is such an old topic weighed down by the nonsensical baggage of eminent names that have come before it. For some reason the combination of trundling theological dogma overly concerned with the divine judgement and punishment of immortal souls, the psychologically pressing intimacy of the question, and our current dearth of information about many aspects of mental life makes the subject of free will (as well as 'consciousness') burdened by a disproportionate number of eminent thinkers from completely unrelated fields all deciding that it is a perfect problem to which they should devote their retirement treatises. The opinions of these thinkers are then bandied back and forth, all with a great deal of undeserved weight given the phenomenal intellectual prestige of the thinkers' earlier works.

While the explanation of my discontent turned a little more vitriolic than I had originally planned, it is nice to have gotten it out of the way. Now I can press on with my own meandering thoughts on the matter. One of the difficulties that plague many discussions of free will is a lack of definition. With such a vague (though intuitive) definition as "do we control our own actions", it is difficult to engage the topic in a meaningful manner. To start with, I think the anyone who brings up the debate must also seriously consider the rejoinder, "Does it matter either way?" To a great extent, the consternation gripping many people over the topic of free will rests with the theological roots I was railing against in my previous paragraph. After all, if we live in a deterministic universe (which itself is not a settled matter, but most people treat it as such), how can we be divinely judged on actions we had no choice but to perform?

Treating the matter outside of the theological realm in the domain of empirical philosophy, I admit the question of free will can still carry some weight when it comes to the issue of earthly justice (such as our criminal justice system). The justice system is a complex entity, however, and, though some people view it as such, does not exist solely for the purpose of delivering retribution. People, including criminals, are remarkably complex dynamical systems. As I mentioned in my previous post, such systems are virtually impossible to fully model, and sometimes impossible to even remotely predict, and thus we have no recourse but to act as if free will exists even if there is no mystical soul or tiny homunculus making choices. In my mind imprisonment and fines therefore remain ethical and necessary institutions. I tried to more fully elucidate my feelings on the matter, but it threatened to take over the rest of my discussion, and I had one more area that I wanted to address. If people take issue with my brief remarks on crime and punishment, let me know and I will try to more completely discuss the matter in another post.

As an atheistic scientist, I strongly doubt the existence of the aforementioned immaterial soul or decision-making homunculus. Of course, there is always the possibility of discovering some previously unsuspected aspect of our mental lives (after all, we only recently uncovered the quantum nature of photosynthesis) which makes our brains fundamentally different than other computing devices, but at the same time that does not mean we will not be able to reproduce our cognitive abilities following such a leap in knowledge. While the strong AI hypothesis (basically, that the brain is a computing device akin to any other computational model) is by no means proven, it is an open question with I think very little current evidence against it. As I said, even if our brain operates in a fundamentally different and as-yet unknown manner from a Turing Machine, every piece of evidence we currently have still points to it being a physical device beholden to physical laws. Damage the brain and you damage your mental faculties. Accepting this physical nature, however, does not equate to relegating our mental lives to that of deterministic automatons. As I have said before, we are still simply too complex to fully predict.

There is one final argument that I would like to address along the lines of neurophysiology. I do not know if I have the argument entirely correct, as I am getting the report of the argument second-hand, but it is a supposed proof against free will. Rather than further mangle the argument by summarizing it again in my own words, I will reproduce it here as it was sent to me:
When I think about moving my finger I am already moving it, and therefore the decision to move my finger must have been made before I thought to do it. Free will would, in this case, be an illusion. Because, the argument goes, there is a slight delay in the signal being sent from my brain to move my finger. Therefore, if I were to have conscious control (and actually making decisions about such things) then I would think about moving my finger, and, half or a quarter of a second later, my finger would move. Instead, at the same time I think about moving my finger, my finger moves, implying to those advancing the argument, that there must be something beyond our control in our heads making us do stuff. So, we do not have free will.
This is, to me, an almost entirely nonsensical argument. As far as I can understand it, the claim is that because one's actions appear to happen in the same instant that one thinks about doing the action, there must be some sort of unconscious automatic decision making device controlling both the thought that the move should be made and the move itself. What the argument is actually doing is basing a conclusion off of the acknowledgement of the latency of some neurological processes but not others. We do not entirely understand at what point one becomes aware of a conscious desire for action, but even assuming that the command is sent to the motor cortex at the same instant it is consciously acknowledged, there is still the latency of the visual and proprioceptive systems in checking that the command was executed. So perhaps there is a two hundred and fifty millisecond delay before one's finger starts to waggle, but one could reasonably expect an equally large or larger delay in the visual and somatosensory cortices as they decide whether or not the waggle is going on, and then report that knowledge back to the administrative cortical regions. What is actually an amazing property of our brain is that it gives the impression of a complete, simultaneous, and coherent picture of the world.

6 comments:

S.C. Kavassalis said...

It always confuses me that people have such a hard time telling the difference between 'faster than our perception' and 'infinitely fast'. Even if they can say to themselves that they know something must have a finite speed, like processes in the brain or light, when it actually comes to applying that to a problem, they get tripped up.

I think if humanity had evolved with a different notion of speed/velocity, then many modern areas of scientific thinking would be much more accessible.

Paul Kishimoto said...

Harpers' daily links post for today included http://www.cambridgeblog.org/2008/09/the-martin-gardner-interview-part-3/ .

I'm not familiar, but apparent Martin Gardner is famous for his math writing; and one long paragraph in the interview begins "You know the problem of consciousness is a hot topic right now."

Coincidence?

Mozglubov said...

Since you are bringing this to my attention for the first time I would say that yes, it is coincidence. However, to a certain extent I think he is right that it is a 'hot topic' right now. Penrose was one of those fellows I was alluding to in my second paragraph, after all.

Anonymous said...

This doesn't really break any new ground, but I've always wondered why it isn't just called "will". The "free" has always seemed unnecessary to me. Your will must be free or it isn't yours at all.

-Regan

Robert said...

Alright, done with school work, and I have a moment of free time, so let me first thank you for doing this post. interesting.

And about the argument that you actually got third hand, the objection you raise was something I had thought of also.

I too find the subject at times a bit tedious, but mostly because I find my knowledge base so limiting that I could not really begin to have an intelligent conversation about it. I have some knowledge on one aspect of it, the knowledge and philosophy, but I think if you engage in the conversation without a neuroscience and biological background also, you are missing something vitally important. And ultimately, I think the question is largely academic. Because, even if we find that free will is not real, I do not think the primary field that would be relevant information, the criminal justice system would, or should change.

Mozglubov said...

After writing this post I came across the study which I think inspired the argument about the hand movements (a study by Benjamin Libet that provided evidence that the conscious decision to move occurred a half second after the neuronal activity setting the movement into motion). This argument makes more sense, but I do not think it is conclusive proof (for one thing, measuring the moment of conscious decision is remarkably imprecise, particularly since we don't know for sure what pattern of brain activity denotes such an incident and must therefore rely on self-reporting - a much less reliable as well as longer process than timing information available from EEG recordings). Anyway, I just thought I should bring that study up for anyone interested.