The Frontal Cortex

Neuroscience and Free Will: The Sequel

My last post on neuroscience and free will generated lots of interesting comments. Please check them out. But I think a few readers misunderstood my ambition. It’s easiest to begin by saying what I wasn’t trying to do: I wasn’t trying to construct a philosophically sound defense of free will (I’m not sure such a thing is possible), or reflect on quantum indeterminacy, or get into a metaphysical debate about the material causality of everything. If you believe, ala Laplace, that the world is governed by a discrete set of material rules (as I do), then, of course, freedom doesn’t really exist. We’re all just matter, blessed with the illusion of being something more. If Laplace’s demon were possible – if we really could know everything about everything – then it’s hard to imagine how that demon could not predict the future, and make our freedom obsolete.

Of course, that demon is a thought experiment. We will never know everything about anything. (See Maxwell and Heisenberg for the physical details.) So, in that sense, freedom is a necessary result of our ignorance. It might be an illusion, but it’s an illusion that will always remain with us, at least for many more centuries. (I’m sure we’ll implode the planet before we disprove our free will.)

So those are my caveats. That said, I also groan when I read articles like the one I referenced in The Economist, which uses an extreme example of a deterministic disease (like a brain tumor in the orbitofrontal cortex) to argue that our free will is somehow endangered by the new knowledge of neuroscience. In fact, I believe that neuroscience, at least so far, has made our instinctual belief in free will less absurd. Fifty years ago, there were two basic schools of thought on the brain: The first school was the genetic determinist school, which argued that the mind is just a by-product of its genetic program. Your fate is fixed at birth. The second school was the behaviorist school, which was, in it’s own way, just as deterministic. The mind was nothing but a network of conditioned instincts. We were completely free to be entrapped by our environment.

Since then, things have gotten much more interesting and complicated. Neural plasticity demonstrates that our brain isn’t set at birth, or at any moment thereafter. You always have the power to change your own neuronal connections, to rewire yourself. (Of course, if you really believe in some sort of cosmic determinism, then your experience is just as determined as your genes. While that’s theoretically possible – perhaps even likely – it’s not something that keeps me awake at night. What would be troubling, however, is if we were strongly genetically determined, since that would demonstrate that our free will is seriously bounded, and bounded in ways that biology could easily describe.) So yes, I still think plasticity is an affirmation of our potential freedom. Think of it this way: if our mind wasn’t plastic, we would be much less free.

As for disorder. . .I never meant to imply that our jumping genes, or developmental noise, or genetic drift, or stochastic gene expression, are random in some numinous, inherently mysterious sort of way. Laplace’s demon could figure out what was going on, and tease out all the “causes” behind our apparent cellular disorder. That said, I think many biologists have been surprised by just how much stochasticity there is inside living organisms. We aren’t a simple input-ouput machine, and our cells play dice all the time. We used to think that the closer you got to the bottom of everything – to life at its most essential and reductionist – the more ordered and neat everything would appear. In other words, we would see that our “elbow room” is an emergent illusion. But that’s not the case. When you drill down to the level of molecular biology that randomness is still there. In fact, it’s more apparent then ever. And I’m not even going to mention the quantum world because, frankly, it makes no sense.

Comments

  1. #1 John Ardington
    December 21, 2006

    Excellent post! But why is neural plasticity less deterministic than behaviorism?

  2. #2 Mr. Me
    December 22, 2006

    I think you’ve strayed far from the sense of “free will” that was being discussed in the Economist. The understanding of free will in the article seems to be about being able to mediate between desires, how much ability did this man with tumor have to restrain his sexual desires, how much do pedophiles have, and is it fair to incarcerate them if they have little ability to restrain themselves. I think we should welcome the death of the belief of an equally distributed free will defined this way, this is the silly kind of self-aggrandizing view that leads people to think that they’ve “willed” themselves to not to be alcoholic or obese while overlooking the more likely mundane reality that their biology simply acts differently to these substances and their ability to tempt. I suspsect neuroscience research will replace our free will understanding of responsiblity with a much richer picture of the individualized struggles people go through involving their moral sense, longterm and short-term desires, and I wouldn’t be the suprised if such research concludes that many types of sex offenders hadve little in the way of restraining themselves from their actions. But that conclusion suggest the opposite of letting them go free for their crimes, these are the very individuals who need to be separated from society because of how little control their can exert over their actions.

    I don’t see neural plasticity or developmental noise playing much of meaninful role in this discussing this sense of free will.

  3. #3 Erin Oakman
    December 22, 2006

    lovely post. Biologists have been surprised by how many stochastic processes occur in the cell. As an example, there are numerous checkpoints in the cell cycle, used in cells to ensure once-and-only-once DNA replication. There are multiple pathways for the repair of DNA damage, through base excision repair, mismatch repair, or homologous recombination.

    As such, randomness and disorder seems to be essential for designing a specific solution for a specific problem. I interpret this disorder to mean that the most reliable systems are made up of equally unreliable parts.

  4. #4 Melinda
    December 29, 2006

    I agree with Mr. Me. While I thoroughly enjoyed both of Jonah’s posts and all the comments on this topic, I think the Economist article had more to do with how science might be challenging our understandings of responsibility and punishment.

    Also, did anyone notice this part of the article?

    “At the moment, the criminal law—in the West, at least—is based on the idea that the criminal exercised a choice: no choice, no criminal. The British government, though, is seeking to change the law in order to lock up people with personality disorders that are thought to make them likely to commit crimes, before any crime is committed…Such disorders are serious pathologies. But the National DNA Database being built up by the British government (which includes material from many innocent people), would already allow the identification of those with milder predispositions to anger and violence. How soon before those people are subject to special surveillance? And if the state chose to carry out such surveillance, recognising that the people in question may pose particular risks merely because of their biology, it could hardly then argue that they were wholly responsible for any crime that they did go on to commit.”

    Now THAT I find frightening. Reminds me of the movie Minority Report…