Flies Don’t Have Free Will
There’s something a little misleading, and frankly badly written, about the New Scientist article on the PLoS ONE paper “Order in Spontaneous Behavior”, both of went online today. Reuters has an article on it, as well.
The New Scientist claims that Brembs et al. were able to show that fruit flies had “rudimentary free will.” Really, it all depends on what you mean by free will. Most people will probably think that free will has something “free” about it, as in having choices of what to do. Given the exact (and I do mean exact) same set of circumstances, one would be able to choose differently.
Scientists mostly believe in a world that is fairly deterministic. Yes, quantum mechanics means that at the lowest level, the world is probably actually random, but the world we live in is the world of averages, where the small randomness pretty much just evens out. That’s why a ball will follow Newton’s laws pretty closely. Thus, free will, if by that you mean truly new decision-making, independent of circumstance, doesn’t really exist. If the world were really set exactly to the same set of circumstances, we would make the same decision again. Our brains are made of molecules and atoms that obey the laws of physics and chemistry, so our thoughts and actions also follow those laws.
Deterministic, however, does not mean predictable! Many scientists have said this before. We really can’t predict most of what goes on in the world; it’s just too complicated, and even our best methods of observation are always just the slightest bit imprecise. Chaos is the name we give to situations in which just that little bit of uncertainty in our measurements makes it almost impossible to predict what will happen in the future, because that small uncertainty gets magnified over time. If I roll a ball down a ramp, I can calculate where it will go most of the time, and the small bit of uncertainty in my observation of where the ball is and how fast its going just gives me an approximately equally small bit of uncertainty as to where the ball will wind up. On the other hand, if I’m looking at the weather, small errors can lead to hugely different outcomes.
Thus, the New Scientist article just becomes incoherent when talking about flies and free will. First, it’s wrong when it says, “If our behaviour is unpredictable, this is only because random events prevent us from responding perfectly to our environment”; I just gave an example in the previous paragraph of a way in which a non-random circumstance can lead to much unpredictability. Second, the article quotes “‘Evolution can fine-tune the level of this spontaneity,’ Brembs says. ‘It’s a rudimentary sort of free will’”; at this point, all it’s doing is confusing the reader. There isn’t actually any true spontaneity, in the philosophical sense, because all the behavior still comes from deterministic principles. There isn’t any free will, because there isn’t any real spontaneity. A lack of predictability from input to output isn’t evidence of spontaneity.
The paper itself is kind of strange. One can’t truly isolate organisms from stimuli. After all, there are plenty of internal feedback loops, and organisms have senses on the insides of their bodies to monitor their own situations, such as pain, hunger, satiation, and so on. Not only that, but the lack of a specific stimulus is itself a stimulus, technically, so…
In addition, the fact that a fly can have an intrinsic program of flight isn’t very surprising. It’s cool, yes, but not surprising. We have this program embedded in all of us, called the genome. It’s the program which, along with the contents of our cells, is used to process outside information. Fruit flies have them, too. The fact that a program exists for us to move in a complicated manner doesn’t mean that we have free will. And the fact that the program is chaotically complicated doesn’t mean fruit flies (or we) have free will. It means that the program is very complicated. That’s all.
UPDATE: There’s a growing list of articles on this paper that are linked to by Bjoern Brembs. He has two responses to all of the commentary, including this more scientific post, and this more popular post.
