—such as honey, for example—a definition does not furnish him with a conception of them. Someone who has not tasted a thing—such as a person told about sugar without having tasted it—cannot conceive of its real nature through words and definitions. Rather, comparisons are offered to give him an approximate idea, and he is told: “It tastes like this,” or “It tastes like this and that.” Such comparison and analogy are not the kind of definition they claim to provide.

The same applies to inwardly perceived things, such as anger, joy, sorrow, distress, knowledge, and the like. Whoever has experienced them has conceived of them; whoever has not experienced them cannot conceive of them through a definition. Thus, someone born blind cannot conceive of colours through a definition, nor can an impotent man conceive of sexual intercourse through a definition.

Therefore, whoever claims that definitions provide conceptions of the real natures of things is asserting a falsehood whose falsity is known through both inward and outward perception.

The fifth argument:

Definitions are merely universal statements, such as “a rational animal,” “an utterance that signifies a meaning,” and the like. Conceiving their meaning does not preclude its applying to more than one thing, even if such shared application is impossible for some other reason. They therefore do not indicate any particular reality as such, but only a universal meaning. Universal meanings exist in the mind, not in external reality. What exists externally, then, cannot be individually identified or known through a definition alone, while what exists in the mind is not the real nature of things. Thus, a definition does not provide a conception of any real nature at all.