Some people call all of these causes, especially those who maintain that a cause means only an indicator—a sign, mark, or proof—not a motive or incentive. Those who say that it may mean an incentive, that is, a motive, say this concerning the causes of actions. As for things other than actions, a cause may be understood as an attribute that necessarily entails another, as being human necessarily entails being an animal, and being an animal necessarily entails being a body, even if neither attribute produces the other.

However, we have explained elsewhere that the same grounds on which one knows that an animal is a body also establish that a human is a body. There we explained that the syllogistic reasoning they describe is of little or no benefit, and that, in rational matters, the grounds establishing the truth of the major premise also establish the truth of its individual instances, among which is the minor premise. Indeed, those same grounds establish the truth of the conclusion.

He then said:

Their contradictions and the unsoundness of their assertions are too numerous to recount. Our purpose here is to discuss “logic” and what they have said about demonstration: they exalt syllogistic reasoning and disparage analogical reasoning, claiming that the latter yields only conjecture and that certainty can be attained only through the former. This is not so. In reality, the two belong to the same category. Sound analogical reasoning is better suited than syllogistic reasoning alone to establishing the desired conclusion, whether with certainty or conjecture.

For this reason, rational people generally employ analogical reasoning more often than syllogistic reasoning. Indeed, syllogistic reasoning concerning a universal matter is valid only through the mediation of analogical reasoning. Every argument used to establish the validity of syllogistic reasoning in certain cases can also be used to establish the validity of analogical reasoning in those