Thomas Aquinas

“ The subjective parts of a virtue are its various species. In this way the parts of prudence, if we take them properly, are the prudence whereby a man rules himself, and the prudence whereby a man governs a multitude, which differ specifically as stated above (Q [47] , A [11] ) . Again, the prudence whereby a multitude is governed, is divided into various species according to the various kinds of multitude. There is the multitude which is united together for some particular purpose; thus an army is gathered together to fight, and the prudence that governs this is called "military." ”

“ I answer that, Parts are of three kinds, namely, "integral," as wall, roof, and foundations are parts of a house; "subjective," as ox and lion are parts of animal; and "potential," as the nutritive and sensitive powers are parts of the soul. Accordingly, parts can be assigned to a virtue in three ways. First, in likeness to integral parts, so that the things which need to concur for the perfect act of a virtue, are called the parts of that virtue. In this way, out of all the things mentioned above, eight may be taken as parts of prudence, namely, the six assigned by Macrobius ”

“ Further, prudence is specifically distinct from science. But politics, economics, logic, rhetoric, physics are sciences. Therefore they are not parts of prudence.
Objection 3: Further, the parts do not exceed the whole. Now the intellective memory or intelligence, reason, sense and docility, belong not only to prudence but also to all the cognitive habits. Therefore they should not be set down as parts of prudence. ”