the speaker depends on knowing that the expression signifies that meaning and has been assigned to it. Knowing that an expression has been assigned to a meaning depends, in turn, on knowing both the meaning and the expression. Thus, the conception of that meaning cannot be derived from an expression that signifies it only once the meaning is known, together with the fact that the expression has been assigned to it and signifies it.

Moreover, whoever defines a single concept in words either defines it through an equivalent single term—its name—or by mentioning an attribute peculiar to it. The term denoting that attribute has the same scope as the name, as with “rational” and “human.” Alternatively, he defines it by mentioning the specific after the general. But conceiving the general and its inclusion of those individual instances presupposes conceiving those instances. If the conception of those instances were derived from the general, circularity would follow.

For the speaker’s and listener’s knowledge that a human is an animal presupposes their conception of both human and animal. Only someone who knows what a human is can know that a human is an animal; and only someone who knows what an animal and a body are can know that an animal is a body. If, then, knowledge of what a human is could be acquired only after knowing what an animal is, while knowledge of what an animal is could be acquired only after knowing the particulars by which it is described, circularity would follow. This is because universal genera have no existence as universals except in