of indifference, of epistemological nullity, an index which indicates: the existence of all these transcendencies, whether I believe in them or not, is not here my concern; this is not the place to make judgments about them; they are entirely irrelevant. All the basic errors of the theory of knowledge go hand in hand with the above mentioned, on the one hand the basic error of psychologism, on the other that of anthropologism and biologism. The; is so exceedingly dangerous, partly because the proper sense of the problem is never made clear and remains totally lost in it, and partly because even those who have become clear about it find it hard to remain clear and slip easily, as their thinking proceeds, back into the temptations of the natural modes of thought and judgment as well as into the false and seductive conceptions of the problems which grow on their basis. KNOWLEDGE BY ACQUAINTANCE AND KNOWLEDGE BY DESCRIPTION IN the preceding chapter we saw that there are two sorts of knowledge: knowledge of things, and knowledge of truths. In this chapter we shall be concerned exclusively with knowledge of things, of which in turn we shall have to distinguish two kinds. Knowledge of things, when it is of the kind we call knowledge by acquaintance, is essentially simpler than any knowledge of truths, and logically independent of knowledge of truths, though it would be rash to assume that human beings ever, in fact, have acquaintance with things without at the same time knowing some truth about them. Knowledge of things by description, on the contrary, always involves, as we shall find in the course of the present chapter, some knowledge of truths as its source and ground. But first of all we must make dear what we mean by 'acquaintance' and what we mean by 'description'. We shall say that we have acquaintance with anything of which we are directly aware, without the intermediary of any process of inference or any knowledge of truths. Thus in the presence of my table I am acquainted with the sense-data that make up the appearance of my table -- its colour, shape, hardness, smoothness, etc.; all these are things of which I am immediately conscious when I am seeing and touching my table. The particular shade of colour that I am seeing may have many things said about it -- I may say that it is brown, that it is rather dark, and so on. But such statements, though they make me know truths about the colour, do not make me know the colour itself any better than I did before: so far a concerns