Every syllogism, then, must contain a universal affirmative; in fact, no universal conclusion can be drawn except from a universal affirmative, and a universal negative yields no universal ruling unless it is accompanied by a universal affirmative.
Clarifying the kinds of “certainties” they recognize that contain no universal proposition:
Since a universal proposition is indispensable to every syllogism, let us note that they restrict the material of certainty to the well-known classes.
First: sensory judgments. It is obvious that the senses do not apprehend anything truly universal; therefore, pure sense perception furnishes no universal proposition that could serve as a premise in a demonstrative proof. When they offer as an example the claim, “Fire burns,” and the like, they have no knowledge of the universality of that claim. What they possess is experience and habit, which belong to analogy; the general judgment they infer is obtained by analogical reasoning, and there is no difference between it and the “comprehensive” syllogism they champion. Even if one reaches the judgment by observing that fire contains a burning power, the assertion that every fire must possess that power is itself a universal judgment.
Should someone argue that the fiery form must necessarily include this power, and that whatever lacks the power is not fire, we would answer: even if that were granted, it still does not establish with certainty that everything possessing that power will burn everything it meets, although that is usually the case. Here analogy, syllogism, habit, and incomplete induction all stand on the same footing. It is well known that anyone who says, “Every fire burns everything it touches,” is mistaken, for the object must be capable of being burnt. We know that fire does not burn everything: it does not burn the salamander, nor the ruby, nor bodies coated with certain pigments. As for extraordinary breaches of natural habit, that is another issue altogether.
I know of no sensory proposition that is both universal and immune to refutation. The universal statement is not itself sensory; the sensory judgment is simply, “This fire burns,” for sense perception grasps only the particular. As for what they call an intellectual judgment, they say that when the soul beholds these particulars it becomes disposed to