Tuesday, March 6, 2012

Epistemic Holism

I have recently become acquainted with Quine's Epistemological Holism, which is the idea that any attempt to support or debunk any one segment of a scientific theory is impossible, because the sensory data administering or interpreting an experiment (or observation of a non-experiment setting) will depend on other parts of that theory or other theories.  Because of this, one cannot confirm any portion of a theory but must either accept or reject the theory as a whole, and even that is almost difficult to do.

That may sound confusing, and it even feels confusing writing it, but this is an illustration I am rather fond of.  Hume taught us to separate the world into things that are true (1) by definition and (2) by sensory data.  For example, in economics, consumers maximize utility by definition, and so one could never test whether they maximize utility or not.  The "max-U" model is true by definition.  It is a tautology, and for that reason always seemed of little value to me.  But then there are sensory data showing that people generally spend money in a way that enhances the amount of goods and services they can consume throughout their lifetime.  Can we use the sensory data to scientifically test the validity of the max-U model?

Quine protested, saying that these two items—things true by definition and things true by sensory datacan never really be separated, making it impossible to really use data on income earnings and expenditures to test whether people maximize their long-run utility.  After all, economists contrived the max-U model / tautology after observing most people don't spend their monthly paycheck in one day or even one month (if savings is separated from spending), and we think to look at people's financial decision in the expectation that they are maximizing utility.

Does this make the scientific method obsolete?  Absolutely, sort of.  In the end, we do often perform science in ways like the scientific method (I'll write more about this soon), but in the end, we can never say whether one theory of consumer behavior is absolutely true or definitely false, and thus turn to pragmatic philosophy to form our conclusions.  I'll also write more about the pragmatic philosophy soon.

Perhaps it is this confusion about how science operates that explains economists' horrible use of the word "theory".  Most of the time economists seem to confuse the concepts of "models" and "theory", and label a mathematical model of consumer behavior as a theory, when the model is derived from the max-U tautology, which can't be tested.  Still, despite this conclusion, economists make intellectual progress constantly, and for reasons described in pragmatic philosophy.

Lawrence Cahoone
The Modern Intellectual Tradition: From Descartes to Derrida
Lecture 28: Quine and the End of Positivism

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