Re: People who think that "rational economic man" is sociopathic might find this a bit humorous

[Julio Huato <juliohuato@xxxxxxxxx>]

Walt,

> when people criticize the economists' idea of man, they are
> really referring to a more specific and less trivial variant of homo
> economicus.

IMO, this kind of reasoning is what is tautological: You're trying to
prove that something admittedly abstract... is abstract!  You don't
need to prove that.  What you call "trivial" (the assumption of the
"homo economicus") is admittedly "trivial."  What is definitely *not*
trivial is the bunch of results that follow from it, when -- as it is
always the case in economic theory -- you combine it with other
premises, e.g., a certain rule descriptive of economic possibilities
or opportunities, consistency conditions at the aggregate level, etc. 
And that's all economic theories (in the sense this term is used in
standard economics) are supposed to do.

Just counterposing "more specific and less trivial variants of homo
economicus" to the "trivial" variant doesn't advance knowledge a bit. 
I don't care how complicated your description of human individual
behavior may be, I could *always* describe a behavior that is even
more complex and, therefore, inclusive of an even larger set of
possible human behaviors than yours.  Always!  If doing theory
consisted of this, then it'd be a game as silly as disputing who could
come up with a larger number.  What has to be done is a bit more
complicated than that:

First off, when the expected gain from improving knowledge justifies
the extra effort, you have to show the consequences of relaxing the
"trivial" premise, thus making the reasoning less "trivial" in
general.  When you do this, you're essentially showing under what
conditions (always under *most* conditions) your theory falls apart. 
That's not trivial either -- you're checking to what extent your
reasoning withstands tweaking the "trivial" premise.  This so-called
"robustness analysis" is an advance in knowledge, but it is rather
modest, incremental.

For a real breakthrough, you need to propose new assumptions (this is
your chance to introduce some particular "nontrivial variant" of the
"homo economicus"), derive from them similarly testable conclusions,
and show that those testable conclusions fit the observable facts
better.  Then, and only then, your theory (and your critique of the
old theory) might be taken seriously.  And if....

> And more relevant to the topic at hand, when people say they
> have found empirical evidence to support some view of human behavior, they
> must be discussing one that is more specific and not trivially true.

IMO, this is a misunderstanding.  The reason why one wants a theory in
the first place is to anticipate what -- under certain conditions --
could happen if some "exogenous" hypothetical event occurred (e.g., a
shock in the economic possibilities or a change in policy).  If a
cheap controlled experiment were an option, then you'd rather conduct
one.  But cheap controlled experiments are not always available in
economics.  So, in order to answer your question and stay on the
cheap, you use abstraction -- you build a theory.  But you want a
theory that -- first and at least -- proves capable of explaining
phenomena that is "trivially true."

That would be the minimal requirement to take seriously an economic
theory.  The more consistent the consequences of your theory are with
observable or "trivially true" facts, the more you'll trust your
theory.  It's like in that old Mexican movie where the "good" guy
(Luis Aguilar) fires at a bottle and breaks it in front of the "bad"
guy (Noé Murayama).  The bottle is "trivial," indeed, but the good guy
is just showing off what his gun can do were the bad guy to misbehave.
 If your theory cannot even rationalize "trivially true" facts, then
why rely on it to account for hypothetical events whose practical
effects have not yet been observed?  What I'm saying here -- subtract
the allusion to Mexican cinema -- is pretty much what Robert Lucas
once wrote about theorizing in economics.

> Again, belief in this tautology certainly does not impede research in
> economics and it may even help some people clarify what they are talking
> about. But it itself is neither an insight of significance or something
> one finds evidence to confirm.

Evidence that people are purposeful in their economic undertakings is
not hidden from view.  But, significant or not, *this* idea is not
something economists set out to prove.

Julio