The same Latin word, “ratio”, is at the origin of two distinct traditions in
Western thought. For the moralists reason
was opposed to passion and, among
more recent writers, to interest. For modern economists, rationality
compatible with the pursuit of interest, is opposed to passion and to irrational
behavior more generally. In a positive characterization, action based on reason
requires impartial motives, with respect both to individuals and to moments of
time, and well-grounded beliefs. Rational action, while neutral with respect to
motives, also requires well-grounded beliefs, although the criteria for
well-groundedness may differ. Reason provides objective grounds for action
(“external reasons”), while rationality offers subjective grounds (“internal reasons”).
In a final contrast, the task of the preceptor of the prince is to inculcate
reason, that of the advisor to the prince to spell out the requirements of
instrumental rationality for achieving his aims, whatever they might be. The "mild
voice of reason” (Madison) is strenghtened by the fact that in most societies it
occupies a privileged place in the normative hierarchy of motivations. Even those
ultimately moved by interest or passion, may want to present their actions,
to themselves or to others, as moved by reason. Much of the impartial behavior
we observe may be due to this civilizing force of hypocrisy and of self-deception.
Rationality and amour-propre may be the handmaidens of reason.