 These complaints about the artificiality of the syllogism inform Valla’s discussion of the three figures of the syllogism. Aristotle had proven the validity of the moods of Figure 2 and 3 by converting them to four moods of Figure 1; and this was taught, for example, by Peter of Spain (thirteenth century) in his widely read handbook on logic, the Summulae logicales, certainly consulted by Valla here. Valla regards this whole business of converting terms and transposing propositions in order to reduce a particular syllogism to one of these four moods of Figure 1 as useless and absurd. While he does not question the validity of these four moods, he believes that there are many deviant syllogisms that are also valid, for instance: God is in every place; Tartarus is a place; therefore, God is in Tartarus. Here the “every” or “all” sign is added to the predicate in the major proposition. He says, moreover, that an entirely singular syllogism can be valid: Homer is the greatest of poets; this man is the greatest of poets; therefore, this man is Homer. And he gives many other examples of such deviant schemes. Valla thus deliberately ignores the criteria employed by Aristotle and his commentators—that at least one premise must be universal, and at least one premise must be affirmative, and that if the conclusion is to be negative, one premise must be negative—or, at any rate, he thinks that they unnecessarily restrict the number of possible valid figures.