Let us first define the issue as clearly as we can. Most
of us have felt •a bodily appetite [see Glossary] prompting us
to indulgences that we judge to be imprudent, and •anger
prompting us to acts that we disapprove of as unjust or
unkind. In such a conflict the desires are said to be irrational
because they drive us to volitions that are opposed
to our deliberate judgments; and it’s when we succeed in
resisting such irrational desires that their impulsive force
is most definitely felt, because in resisting them we have
make a voluntary effort somewhat like that of muscular
exertion. Desires of this kind are often at work when we
aren’t giving any thought to our duty or our interests, as
when an ordinary healthy man eats his dinner. It seems best
to call these desires ‘non-rational’ rather than ‘irrational’.
Despite these labels, the more important of these desires
are normally accompanied by intellectual processes. Some
impulses to action do indeed seem to operate ‘blindly’ or
‘instinctively’, with no definite thought about either •the
end the action aims at or •the means by which it is to be