themselves; he makes them bitter. For the tenth tropos the same sort of argument is applied to morals. Morality is entirely conventional and acquired. Different nations differ widely in their estimate of moral distinctions. Hence these distinctions are altogether relative. We can form no conception of anything as good or as bad in itself, but only a conception of it as good or as bad in relation to ourselves. These specimens may be sufficient as examples of the Sceptical line of argumentation. Some of them, it may be owned, are rather frivolous, and on that account, as well as from the consideration that they are all reducible as I have said, to the principle of relativity, it is not necessary to make any further mention of the τρόποι, either of the earlier or of the later Sceptics.
13. The Sceptical conclusions may be summed up thus: first, There is no possibility of knowledge, in the strict sense of the word, because we can never know things as they are in themselves, but only as they are coloured and modified by our faculties of cognition, that is, we cannot know them as they are, but only as they are not; secondly, There is no standard or criterion of truth, because the senses and understanding of different beings differ widely, and no one of them has a better title than any other to set itself up as the criterion of the truth; thirdly, There is no stability in definitions, because a definition of a thing which may recommend itself to one intelligence will not recommend itself to a differently
