I had an interesting conversation about microfoundations at David Andolfatto's blog.
David's post comes on the heels of a number of other posts by various bloggers. See here, here, here, here, here, here, and here. Here is David:
A narrow view of "microfoundations" is reflected in the idea that the methodology of microeconomic theory (specifying individual preferences, information sets, endowments, constraints, together with an equilibrium concept) can and should be brought to bear on macroeconomic questions. This is in contrast to an earlier methodology that specified and estimated behavioral relations at the aggregate level. (One can legitimately weigh the pros and cons of these (and other) methodologies.)
Not many macro models are "microfounded" in a pure sense. Almost all models make at least some assumptions that may be viewed as ad hoc and provisional (subject to further investigation). I think of an ad hoc assumption as a restriction on behavior that is inconsistent with other aspects of the model, like maximizing behavior.
...just take a look at one of the dominant paradigms in macroeconomic theory--the New Keynesian framework. As anyone who is familiar with the paradigm knows, it is built around models that embed ad hoc assumptions reflecting the alleged costs associated with nominal wage and price adjustments in auction-like settings
...By the way, I like to take a broader view of "microfoundations;" or, rather, the search for microfoundations. Microfoundations does not, in my mind, mean stopping at preferences and technology, or anywhere else, for that matter. It simply means seeking a deeper understanding.I like this broader view. At some point, perhaps, microeconomics will find its own microfoundations in behavioral economics and psychology, which in turn will be microfounded in neuroscience, which in turn...
This post from Leigh Caldwell describes this idea.