there would be a definition of non-essences and of non-entities, since it is possible even for non-entities to have a signification. Again, all sentences will be definitions, for we might give a name to any sentence, so that we might all discuss in definitions, and the Iliad would be a definition. Besides, no science would demonstrate that this name signifies this thing, neither therefore do definitions manifest this.
From these things therefore it appears that neither definition nor syllogism are the same thing, nor are syllogism and definition of the same thing, moreover that definition neither demonstrates nor shows any thing, and that we can know what a thing is neither by definition nor by demonstration.
Chapter 8
Moreover we must consider which of these things is well, and which is not well asserted, also what definition is, and whether there is in a certain way or by no means a demonstration and definition of what a thing is. Now since it is the same thing as we have said to know what a thing is, and to know the cause wherefore it is, and the reason of this is, that there is a certain cause, and this is either the same or another, and if it is another, it is either demonstrable or indemonstrable; if then it is another, and is capable of demonstration, it is necessary that the cause should be a medium, and should be demonstrated in the first figure, for that which is demonstrated is both universal and affirmative. Now one method will be that which has been now investigated, viz. to demonstrate what a thing is through something else, for of those things which
