What's with the pessimism?

From Wikimedia Commons.

I remember a conversation in grad school with one of the postdocs in our department about some new result in biology over the course of which he called me a "hardcore reductionist" because of something I said that was rather reductionist. However, I'd really just characterize my view as optimistic about figuring out stuff.

A Twitter conversation with Eric Lonergan (see here) about eclecticism in macroeconomics reminded me about my optimism; I realize many people do not share it.

Eric brought up Hume's "uniformity of nature" -- the basic assumption that goes into any quest for universal laws -- suggesting it might not exist in economics. I agreed it was possible -- and always should be in the back of your mind lest you start seeing pattern where none exists. But do we know that for certain? No.

While Eric's view is closer to a case that we should view various economic models as approximations to a (potentially unknowable) theory, Dani Rodrik's push for an eclectic interpretation of macroeconomic modeling suggests a kind of resignation. He says we should give up looking for a big unifying theory of economics because it does not exist. Rodrik's reasoning must be that he and his colleagues haven't found it, therefore it must not exist.

And (via Mark Thoma) I read Daniel Little:

... Does the phenomenon of [social phenomena] admit of a scientific treatment along the lines of Galileo, Newton, or Lavoisier? 

The answer is resoundingly no. Such a goal displays a fundamental misunderstanding of the social world. Social things and processes at every level are the contingent and interactive result of the activities of individual actors. Individuals are influenced by the social environment in which they live; so there is no reductionist strategy available here, reducing social properties to purely individual properties.

This commits two logical fallacies. The current lack of  a scientific treatment does not mean one does not exist. And the lack of a reductionist strategy does not mean there is a lack of any strategy.

As I commented on Little's blog, even his specific example of not being able to begin to understand a city is contradicted by the existence of work by  M. A. O. Ayeni. From the abstract:

For these uses of the system approach, the concept of entropy, introduced from both thermodynamics and information theory, plays a significant role. ... It emerges that the concept of entropy can be used in studies of urban spatial structure as an integrating concept provided that our terms are defined explicitly and unambiguously.

Apparently Little already knows the final result of this research program. However given that he thinks reduction to agents is the only strategy, he probably hasn't considered maximum entropy approaches.

Now I can understand the pessimism in each case. In economics, we seem to be at the end of a failed research program (microfounded rational utility maximization) that began in the 70s. Pessimism is a natural outcome. And in social science (writ large), there is a bias towards consequential human action rather than mathematical laws. I happen to think there is a lot of room for the latter, but that's because I'm pessimistic about human free will.

But even without the information transfer framework for economics, I'd still be optimistic about finding mathematical explanations of most statistical regularities.

The truth is: we don't know. Lack of a big mathematical theoretical framework (or lack of a successful one) is not evidence one does not exist.