These facts may seem to give countenance to the general assertion that to think a thing good is to prefer it or approve it, in the sense in which preference and approval denote certain kinds of will or feeling. It seems to be always true that when we thus prefer or approve, there is included in that fact the fact that we think good; and it is certainly true, in an immense majority of instances, that when we think good, we also prefer or approve. It is natural enough, then, to say that to think good is to prefer. And what more natural than to add: When I say a thing is good, I mean that I prefer it? And yet this natural addition involves a gross confusion. Even if it be true that to think good is the same thing as to prefer (which, as we have seen, is never true in the sense that they are absolutely identical; and not always true in the sense that they occur together), yet it is not true that what you think, when you think a thing good, is that you prefer it. Even if your thinking the thing good is the same thing as your preference of it, yet the goodness of the thing—that of which you think—is, for that very reason, obviously not the same thing as your preference of it. WHether you have a certain thought or not is one question; and whether what you think is true is quite a different one, upon which the answer to the first has not the least bearing. The fact that you prefer a thing does not tend to shew that the thing is good; even if it does shew that you think it so. (§ 80 ¶ 1)

It seems to be owing to this confusion, that the question What is good? is thought to be identical with the question What is preferred? It is said, with sufficient truth, that you would never know a thing was good unless you preferred it, just as you would never know a thing existed unless you perceived it. But it is added, and this is false, that you would never know a thing was good unless you knew that you preferred it, or that it existed unless knew that you perceived it. And it is finally added, and this is utterly false, that you cannot distinguish the fact that a thing is good from the fact that you prefer it, or the fact that it exists from the fact that you perceive it. It is often pointed out that I cannot at any given moment distinguish what is true from what I think so: and this is true. But though I cannot distinguish what is true from what I think so, I always can distinguish what I mean by saying that it is true from what I mean by saying that I think so. For I understand the meaning of the supposition that what I think true may nevertheless be false. When, therefore, I assert that it is true I mean to assert something different from the fact that I think so. What I think, namely that something is true, is always quite distinct from the fact that I think it. The assertion that it is true does not even include the assertion that I think it so; although, of course, whenever I do think a thing true, it is, as a matter of fact, also true that I do think it. This tautologous proposition that for a thing to be thought true it is necessary that it should be thought is, however, commonly identified with the proposition that for a thing to be true it is necessary that it should be thought. A very little reflection should suffice to convince anyone that this identification is erroneous; and a very little more will shew that, if so, we must mean by true something which includes no reference to thinking or to any other psychical fact. It may be difficult to discover precisely what we mean—to hold the object in question before us, so as to compare it with other objects: but that we do mean something distinct and unique can no longer be matter of doubt. That to be true means to be thought in a certain way is, therefore, certainly false. Yet this assertion plays the most essential part in Kant's Copernican revolution of philosophy, and renders worthless the whole mass of modern literature, to which that revolution has given rise, and which is called Epistemology. Kant held that what was unified in a certain manner by the synthetic activity of thought was ipso facto true: that this was the very meaning of the word. Whereas it is plain that the only connection which can possibly hold between being true and being thought in a certain way, is that the latter should be a criterion or test of the former. In order, however, to establish that it is so, it would be necessary to establish by the methods of induction that what was true was always thought in a certain way. Modern Epistemology dispenses with this long and difficult investigation at the cost of the self-contradictory assumption that truth and the criterion of truth are one and the same thing. (§ 80 ¶ 2)