"explanation" of course, but again it is not customary to use the word in this connection ; to most people it would sound strange to speak of epistemology as the "theory of explanation" instead of "Theory of knowledge". But after having made the distinction I think there is no danger of confusion for us; and wherever we want to emphasise that we are not speaking of mere factual knowledge we can always use the term "explanation".
But unfortunately there is another very common use of the word "knowledge" which we shall be very careful to avoid, for in my opinion it has given rise to the most terrible mistakes — I should even say, to the most fundamental mistake of the philosophy of all times. The misuse I am speaking of occurs when the word "knowledge" is applied to what is often called — immediate awareness" or — and this is the most famous technical term "intuition". When I hear a sound or see a colour we often say that by these very acts of hearing or seeing I come to "know" what a sound is or what a colour is, — or it would be more cautious to say; I get knowledge of that particular sound I happen to be hearing, or the particular colour I am seeing, for as you probably know, a great deal of meditation has been devoted to the question concerning the transition from these particulars to the universal "colour" and "sound".
The particular colour or sound or feeling that is present "in my mind" at a particular time is exactly what we called "content" in the first lecture, and you can easily guess the bearing of our present question to our main issue. — When we look at our leaf, we get an immediate acquaintance with a particular quality of "green". Is there any reason or justification to speak of this acquaintance as a kind of "knowledge"? The use of our words, i.e. our definitions, should be determined entirely from the practical point of view, and we ought not to employ the same word for two things which have nothing in common in their nature and purpose. Mr. Bertrand Russell distinguishes between "knowledge by acquaintance" and "knowledge by description" but why should the first be called "knowledge" at all? The word "acquaintance" alone seems to me sufficient, and then we can emphasize the distinction between acquaintance and knowledge. There is no similarity of meaning between the two.
Since acquaintance has to do with content we are bound to blunder whenever we try to speak of it. In saying that we "know" content by
