Whether Shrewdness Is Part of Prudence?
Objection 1: It would seem that shrewdness is not a part of prudence.
For shrewdness consists in easily finding the middle term for
demonstrations, as stated in _Poster._ i, 34. Now the reasoning of
prudence is not a demonstration since it deals with contingencies.
Therefore shrewdness does not pertain to prudence.
Obj. 2: Further, good counsel pertains to prudence according to
_Ethic._ vi, 5, 7, 9. Now there is no place in good counsel for
shrewdness [*Ethic. vi, 9; Poster. i, 34] which is a kind of
_eustochia_, i.e. "a happy conjecture": for the latter is
"unreasoning and rapid," whereas counsel needs to be slow, as stated
in _Ethic._ vi, 9. Therefore shrewdness should not be accounted a
part of prudence.
Obj. 3: Further, shrewdness as stated above (Q. 48) is a "happy
conjecture." Now it belongs to rhetoricians to make use of
conjectures. Therefore shrewdness belongs to rhetoric rather than to
prudence.
_On the contrary,_ Isidore says (Etym. x): "A solicitous man is one
who is shrewd and alert (_solers citus_)." But solicitude belongs to
prudence, as stated above (Q. 47, A. 9). Therefore shrewdness does
also.
_I answer that,_ Prudence consists in a right estimate about matters
of action. Now a right estimate or opinion is acquired in two ways,
both in practical and in speculative matters, first by discovering it
oneself, secondly by learning it from others. Now just as docility
consists in a man being well disposed to acquire a right opinion from
another man, so shrewdness is an apt disposition to acquire a right
estimate by oneself, yet so that shrewdness be taken for _eustochia_,
of which it is a part. For _eustochia_ is a happy conjecture about
any matter, while shrewdness is "an easy and rapid conjecture in
finding the middle term" (Poster. i, 34). Nevertheless the
philosopher [*Andronicus; Cf. Q. 48, Obj. 1] who calls shrewdness a
part of prudence, takes it for _eustochia_, in general, hence he
says: "Shrewdness is a habit whereby congruities are discovered
rapidly."
Reply Obj. 1: Shrewdness is concerned with the discovery of the
middle term not only in demonstrative, but also in practical
syllogisms, as, for instance, when two men are seen to be friends
they are reckoned to be enemies of a third one, as the Philosopher
says (Poster. i, 34). In this way shrewdness belongs to prudence.
Reply Obj. 2: The Philosopher adduces the true reason (Ethic. vi, 9)
to prove that _euboulia_, i.e. good counsel, is not _eustochia_,
which is commended for grasping quickly what should be done. Now a
man may take good counsel, though he be long and slow in so doing,
and yet this does not discount the utility of a happy conjecture in
taking good counsel: indeed it is sometimes a necessity, when, for
instance, something has to be done without warning. It is for this
reason that shrewdness is fittingly reckoned a part of prudence.
Reply Obj. 3: Rhetoric also reasons about practical matters,
wherefore nothing hinders the same thing belonging both to rhetoric
and prudence. Nevertheless, conjecture is taken here not only in the
sense in which it is employed by rhetoricians, but also as applicable
to all matters whatsoever wherein man is said to conjecture the truth.
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