terms together, that the consciousness, taking cognisance of the work accomplished, verifies the existence of a resemblance, and that this resemblance explains the suggestion.
Second objection: we are told that the relations between the objects—that is, the principal categories—must be of a mental nature, because they are a priori. That they are a priori means that they are at once anterior and superior to the experience. Let us see what this argument is worth.
It appears that it is somewhat misused. With regard to many of the categories, we are content to lay down the necessity of an abstract idea in order to explain the comprehension of a concrete one. It is said, for example: how can it be perceived that two sensations are successive, if we do not already possess the idea of time? The argument is not very convincing, because, for every kind of concrete perception it is possible to establish an abstract category.
It might be said of colour that it is impossible to perceive it unless it is known beforehand what colour is; and so on for a heap of other things. A more serious argument consists in saying that relations are a priori because they have a character of universality and of necessity which is not explained by experience, this last being always contingent and peculiar. But it is not necessary