ABSTRACT
In the last two chapters I referred to the tendency, on the part of philosophers, to impose abnormal requirements on familiar concepts, the requirements being such as to make the concept inapplicable. Nowhere has this been more evident than in the case of knowledge. But how can the existence of knowledge be doubted? The word ‘know’ is used every day with regard to the future, the past, unobserved objects, the feelings of other people, and so on. How can it be denied that we have knowledge in these and other areas? If knowledge were a kind of substance or process, then its existence would not be thought to follow from the mere use of the word. The fact that there is a use for the words ‘fairy’ and ‘black bile’ would not prevent us from doubting whether these things exist. But ‘knowledge’ does not stand for a thing or substance. And when sceptics deny the existence of knowledge, it is not this kind of existence that is at issue.
