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can then show that the particular methods internal to the various domains
have in each case an authority that is inexhaustible. Now, an inexhaustible
authority cannot be completely explained away. An inexhaustible authori–
ty cannot undergo reduction wi thout remainder to a causal story about
biology or social condi tioning or whatever. Firstly, because the authori ty of
reason applies to the reductive analyses themselves, that is to say, the analy–
ses can only show themselves to be correct by appealing to logic, or
to
empirical evidence, or to scientific theory. This is especially obvious when
reductive analyses compete wi th each other; it would not be possible to
adjudicate between biological and sociological explanations, for instance, if
reason had no independent force. Global relativism claims that reason is
nothing over and above a natural fact about human beings but natural facts
cannot have authority, least of all inexhaustible authority. Natural facts are
just there. You might as well say that the rockiness of a rock or the straw–
ness of straw has authority.
Having explained his general strategy, Nagel goes on to discuss the
nature of language and to demonstrate the authori ty of the internal meth–
ods of logic, mathematics, science, and ethics.
He
is extremely successful in
the case of logic and mathematics, less sure-footed on science, and stum–
bles once or twice when coping wi th ethics.
Nagel acknowledges that the authority of moral reasoning has always
seemed less secure than that of logic and mathematics. But he rightly points
out that human beings cannot escape the need to decide how to act any
more than we can escape decisions about what to believe. To my n1.ind,
though, the inescapable need to make decisions about what to do does not
by itself imply that the methods of ethics have inexhaustible authority.
Nagel's defense of moral reasoning consists largely in a reprise of
arguments taken from an earlier book,
Tile Possibility ofAltruism,
and like
those it combines an assumption that the demands of a prudent ego are
self-evidently rational with the assertion that all reasons are universal in
scope "by definition." Even if he is right, there remains a question about
whether the two supposedly necessary truths can be brought together in
such a way as
to
motivate action. And as it happens neither the definition
nor the assumption of self-evidence seems to be absolutely unavoidable.
When I quizzed my students about the matter most of the men agreed
that the rationality of prudence is self-evident and most of the women
said it is not. There isn't any way to convince a student that he or she is
wrong on this point. One might try the Bloomsbury ploy described by
J.
M. Keynes: "Oh' (sneer) So you think that, do you?" but that ploy does–
n't always work. Surely the lesson, then, is that Nagel's assumption is
attractive to some and not
to
others (a matter of temperament), and that
it is not self-evident.
