Scott Adams (the Dilbert guy) has a thing about free will. He visits the topic often on his blog, and this post of his is supposed to prove beyond a shadow of a doubt that free will does not exist.

His basic conclusion, as I understand it, is that unpredictability does not equate to free will. That is, what people think of as "free will" is actually just "unpredictability" -- so when you choose to get a jelly donut or a glazed donut, you are not exercising "free will" or "choice" at all, you are merely displaying "unpredictability."

But now that I start writing it out, I'm not following his logic anymore. If picking jelly or glazed is not "free will" or "choice," then what else could it possibly be? The only other alternative is that one's actions are pre-programmed, but that would seem to run counter to Scott's atheist beliefs, and run smack into the Evangelical belief that "God has a plan for everything." (Scott does often call humans "moist robots," though, so maybe he's really an Evangelical at heart.)

Anyway, back to his post. His example to disprove free will is a programmed robot. He throws a random number generator into the programming so that its actions are not predictable, even by the programmer. I think his example breaks down though, because, the robot's actions will be predictable... the robot will (or should, if the programmer didn't introduce any bugs) always respond the same way to each possible condition it sees. You might think the random number generator would prevent that, but the random numbers are each conditions unto themselves. If the environment is in one condition at a particular time, and a particular random number occurs, the robot will always perform the same action. (Nerd note: I'm grossly simplifying the programming details here.)

Here's how I would define free will: A person with free will might respond differently to two situations with the exact same conditions.

Of course, when we go down to the quantum level, one could probably argue that no two situations could ever possibly be the same, thus eliminating the existence of free will again. For example, I might pick a jelly donut when it's raining, but the next time it's raining I might pick a glazed donut. I responded differently to the "raining" condition, thus exhibiting free will and proving I'm not a pre-programmed robot. Unfortunately, there are millions of other conditions going on from day to day besides rain, so I might be responding to different stimuli after all. The temperature might have been different, or the barometric pressure might have been different, or the number of ants under the house might have been different, or the number of decaying radioactive isotopes under my fingernails might have been different.

When you start looking at it on that level, it's more-or-less impossible to prove or disprove the existence of free will. There's no way anyone could design an experiment to observe a person's reactions to the exact same conditions over multiple trials, because of those pesky decaying isotopes again. One would always be able to say, "well obviously, since this particular isotope had decayed to 52.768% at the time of the experiment, you picked the jelly donut. If it had been at 52.767%, the conditions would have been different and you would have gone for the glazed. Therefore, there is no free will."

But the problem with disproving free will -- for Scott the atheist, at least -- is that it more-or-less proves that someone or something must have pre-programmed the universe. So in a way, Scott's belief that there is no free will is the same as another person's belief in God, which is a perplexing parallel. They both boil down to believing the unknowable.

Thomas Krehbiel writes The Krehbiel Strikes Back, a moderate commentary on news, media, politics, and culture.