Honors | Rationality and Its Limits: A Multidisciplinary Perspective
H205 | 0019 | J. Weinberg

4:00-5:15P  MW  BH 331

"Aristotle proposed to define humans as "rational animals". But that
prompts the question: what is rationality, anyway? And, more to the
point, are we humans really so rational? What does it mean for a
belief to be rational or irrational, and how often (if ever!) do we
have such beliefs? The focus of this course will be to explore the
potential -- and limits -- of three different academic perspectives on
these questions: logical, philosophical, and psychological. Thus we
will consider three possible types of definitions of rationality:
(a) a rational belief is one that is proved;
(b) a rational belief is one that you can argue for with good reasons;
(c) a rational belief is one that is produced by reliable
psychological mechanisms

In the first stage of the course, we will consider the notion of a
formal proof. The attraction of the science of logic is that it holds
the promise of an objective, decidable notion of rationality. We will
develop the techniques of representing sentence structures in symbolic
forms, so that we can see how purely abstract relations between some
sentences can give us a sense of one sentence 'rationally following'
from some other sentences. We will spend some time of the actual
mechanics of doing proofs, but the major docus will be on
understanding what inferences a given symbolic system can -- or cannot
-- show to be rational. This section will culminate with an intuitive
presentation of Goedel's infamous proof of the 'incompleteness of
mathematics' -- namely, if we construct a logical system powerful
enough to perform the inferences of arithmetic, then we can show that
it has inferences that we know should be rational, but which the
system nonetheless cannot prove.

Having explored the power, but ultimate disappointment, of formal
logic, we will next consider the philosophical tradition of
epistemology. What would it mean for a belief to be held on good
reasons? We will confront one of the most ancient paradoxes in
philosophy, from the ancient skeptical philosophers. You cannot offer
just any ol' reasons arbitrary reason for a belief, but it seems
rather that you must have reasons_for your reasons_. And those
reasons'have to have reasons...and so on. So, it can appear that
rationality is unattainable: if the 'chain of reasons' comes to an
end, then its an arbitrary, irrational stopping point; if the chain of
reasons doubles back on itself, then the reasoning is circular; and it
is impossible for the chain of reasons to extend on into infinity. We
will consider the various ways philosophers have tried to wriggle out
of this puzzle -- maybe_some_stopping places are not arbitrary?
May_sometimes_it's ok to argue in a circle? Perhaps an infinite chain
of reasons is not as impossible as we thought? But at the end of this
section, we will perhaps want to explore a notion of rationality that
does not depend on offering reasons in an argument.

In the final section of the course, we will turn to cognitive
psychology. Perhaps the important thing for a rational belief is not
that we have reasons for it, but that the part of our minds that
formed the belief did so_in the right way_. Thus, we turn to the
science of the mind -- and the problematic data there that seems to
indicate that, by and large, our thinking systems are a bit of a mess.
Some psychologists have argued that, instead of the uniformly reliable
systems we might have hoped to have, our minds are full or rough,
fallible, rule-of-thumb heuristics. We will reconstruct some of these
classic experiments (on each other, or on students' unsuspecting
dormmates, etc.). But we will end this section on a cautiously
optimistic note: recently, the rise of 'evolutionary psychology' has
suggested that, if we view these heuristics from the point of view of
giving us -- or, rather, our evolutionary ancestors -- fast and
effective means of thinking about our/their environments.

Students will produce a total of 4 projects -- a set of logic
exercises; a short philosophy paper; and a psychology laboratory
report; and, at the end of the course, a longer paper in which the
student will articulate and defend his or her own preferred theory of
rationality, building on the notions we will have developed through
the semester."