CHAPTER VII.[1]
ON THE RELATION OF THE CONCRETE KNOWLEDGE OF PERCEPTION TO ABSTRACT KNOWLEDGE.
It has been shown that conceptions derive their material from knowledge of perception, and therefore the entire structure of our world of thought rests upon the world of perception. We must therefore be able to go back from every conception, even if only indirectly through intermediate conceptions, to the perceptions from which it is either itself directly derived or those conceptions are derived of which it is again an abstraction. That is to say, we must be able to support it with perceptions which stand to the abstractions in the relation of examples. These perceptions thus afford the real content of all our thought, and whenever they are wanting we have not had conceptions but mere words in our heads. In this respect our intellect is like a bank, which, if it is to be sound, must have cash in its safe, so as to be able to meet all the notes it has issued, in case of demand; the perceptions are the cash; the conceptions are the notes. In this sense the perceptions might very appropriately be called primary, and the conceptions, on the other hand, secondary ideas. Not quite so aptly, the Schoolmen, following the example of Aristotle (Metaph., vi. 11, xi. 1), called real things substantiæ primæ, and the conceptions substantiæ secundæ. Books impart only secondary ideas. Mere conceptions of a thing without perception give only a general knowledge of it. We only have a thorough understanding of things and their relations so far as we are able to represent them
1 This chapter is connected with § 12 of the first volume.
- ↑ 1
