Jerry Fodor recently (4 March) gave a talk entitled “What Darwin Got Wrong” at the CUNY Graduate Center in New York City. He accused Darwin of committing the intentional fallacy and hence said, straight out, that he didn’t believe in the theory of evolution.
So what exactly does Fodor think Darwin got wrong?
He believes that the theory of evolution is vacuously true (or just wrong) and hence not a worthwhile theory of science.
You can sink your teeth into the argument in this synopsis, but be forewarned, the argument is good: you may, depending upon your convictions, be forced to disbelieve the theory of evolution. However, it doesn’t identify all the critical presuppositions that Fodor uses (this is no fault of the synopsis; it is accurate to the argument), and these are what are really necessary to show where Fodor is mistaken.
[The one day, the ONE DAY, a year that there is a talk specifically having to do with my work on philosophy of science and biology and I have an international plane flight to catch only a few hours after the talk. I happily was able to catch the whole talk but I couldn’t stay for the question and answer session. So I did the only thing I could think of and asked my questions during the break and ran out of the building (literally). The following quote is accurate as far as I can remember, and, as far as I know, I am the only one who heard him say it.]
“Natural Selection is statistical. It just is.”
What does this mean?
In my world Natural Selection is a force. It is a force that changes species over time. For example lets take some species of bacteria. A few of the bacteria in that species adapt to be able to eat a novel sort of food and this gives them an advantage over the others. Eventually these bacteria are able to replicate more often and eventually most of the overall bacteria population has this trait. Hence the species has changed from not having a certain property to having a certain property. If you ask me what caused this change in the bacteria population, I would say that Natural Selection was the cause or force behind the change in the species.
There are two ways I can think of interpreting Fodor’s statement: 1) Natural Selection is statistical and not a force. 2) Natural Selection is statistical and a force.
Taking the first interpretation that Natural Selection is statistical and not a force, how are we to understand my little story about the bacteria above? Perhaps: “The change in the physiology of certain bacteria statistically increased their fitness over the other bacteria. Hence those bacteria were able to replicate more readily and eventually outnumber bacteria without that trait.” The thing that changed the species was the increased fitness, which was caused by the physiological change. Natural Selection was the result of this change and can be observed statistically by seeing how individual organisms with that trait were able to fair better than their compatriots. Therefore Natural Selection is a non-causal description or explanation of how species change.
This is immediately problematic because a description or explanation is always describing or explaining something that already exists: it will always be vacuously true, e.g. snow is white if(f) snow is white, or it will just be wrong, e.g. snow is blue. Therefore, by assuming that Natural Selection is statistical and not a force, we have begged the question against Natural Selection.
Now let’s take a look at option 2: Natural Selection is statistical and a force.
As a force Natural Selection is the cause of things. Causes can work directly, such as one object striking another and causing it to change direction, or as a field does, by creating an environmental disturbance of some sort which affects the object. Natural Selection falls (more or less) into the latter category: the environment changes and this causes species to change, to adapt.
Is Natural Selection statistical under this interpretation? No. If Natural Selection acts in the way a field does, by changing the environment which then affects things in that environment, then at every point there is some local interaction between the field and the object. Otherwise we have a theory of action-at-a-distance, i.e. one thing is causing something to happen without any way for us to identify the underlying process: a theory of magic. If something is acting statistically, then it is acting at different places with no known connection between them. However, evolution comes with a ready made theory of local interactions: every organism is constantly struggling for survival. The struggle for survival ensures that there is a connection between Natural Selection and the environment. Therefore if Natural Selection is a force, it cannot also be statistical.
[I can confirm that Fodor believed that the struggle for survival was not critical because earlier in our brief conversation he said that the struggle for survival was merely a metaphor. I responded by saying that Natural Selection is a metaphor then too, but he disagreed.]
In conclusion, by assuming that Natural Selection is statistical and ignoring the local interactions in the struggle for survival, Fodor has begged the question against evolution. As a statistical non-causal explanation, Natural Selection cannot act as a force in evolution. Once evolution has lost it’s driving force, it no longer can function as a working scientific theory. However, believing that Natural Selection is a non-causal explanation is unfounded. The theory of evolution provides a method – the struggle for survival – that explains how Natural Selection causes change in species via the environment, and ignoring this is what Fodor got wrong.
[EDIT: I’ve put up a new analysis (24 March 2010) of Fodor’s argument here: Hypotheses Natura Non Fingo]