Chapter 5
We must describe what definition, property, genus, and accident are. Now definition is a sentence signifying what a thing is: and either a sentence is employed instead of a noun, or a sentence instead of a sentence, since it is possible to define some things which are signified by a sentence. As many however as in some way or other make the explanation by a noun, evidently do not explain the definition of the thing, since every definition is a certain sentence. Still we must refer a thing of this kind to definition, as that the becoming is beautiful; in like manner also whether sense and science are the same or different, since about these definitions, whether they are the same or different, there is a very great discussion. In short, however, all things may be called definitive which are under the same method with definitions, but that all which have been spoken of are of this kind is evident from these (considerations). For when we are able to argue that a thing is the same and that it is different, we shall by the same manner be well supplied with arguments about definitions, since when we have shown that it is not the same we shall have upset the definition. Still what is now said is not converted, since it is not enough to construct a definition to show that it is the same, but for the subversion of definition it is sufficient to show that it is not the same thing.
