I read on this site: http://plato.stanford.edu/entries/methodological-individualism/#2
Is this true and does it represent one of the ways in which Hayek later diverged from the Austrian School?
I can’t answer for certain, but I know that Garrison tells of an incident late in his life where Hayek laments that he turned his attention from traditional Austrian methodology to pursue “other projects.” You can find a reference to this by going to the Mises media section and listening to Garrison’s lecture on the business cycle, where he tells the story. Personally, I’d take issue with the idea that evolutionary explanations somehow conflicts with methodological individualism, as long as the level of evolution is the individual. I remember seeing somewhere, I can’t remember where, an Austrian response to the selfish gene argument. The upshot, as I remember it, was that even if our genes “give” us free will because that is what best passes on our genes, we still have free will. It doesn’t go away if you identify the source. This sounds like something Dr. Long would say, but I don’t know if he said it.
That is more or less what Dr Long said, in one of his lectures on The Foundations of Libertarian ethics. He discusses it when speaking of the natural end of the entity in question. Even Dawkins, for instance, is not a genetic determinist.
Roy Cordato found this, which shows that the statement about Hayek is just wron:
Here’s a quote from Hayek LL&L Vol.3 (1979):
“the whole of the so-called welfare economics, which pretends to base its arguments on interpersonal comparisons of ascertainable utilities, lacks all scientific foundation. The fact that most of us believe that they can judge which of the several needs of two or more persons are more important, does not prove either that there is any objective basis for this, nor that we can form such a conceptions about people whom we do not know individually. The idea of basing coercive actions by government on such fantasies is clearly an absurdity.”
Thanks for that jtucker. 
I’m sorry, but how does that statement reflect Hayek’s stance on methodological individualism? As far as I’m aware, methodological individualism has nothing to do with interpersonal utility comparison.
Well, I guess I thought it would be obvious. A major proposition of meth indiv is that utility can only be understood in terms of individuals. .