If this view of the nature of the mental act of knowing is accepted, we are able to understand how false opinion {84} is consistent with the fact that all knowledge is truth. We escape both the alternatives that seemed to Socrates the only possible ones. "When a man has a false opinion, does he think that which he knows to be some other thing which he knows, and knowing both is he at the same time ignorant of both? Or does he think of something which he does not know as some other thing which he does not know?" No, neither; in error he thinks that something that he knows is in a relation that he knows to some other thing that he knows, when in fact that relation is not relating the two things. The false proposition is not one in which the constituent terms and relations are unknown or non-existent, but one in which a combination of these terms and relations is thought to exist when in fact it does not exist; and the true proposition is that in which the combination thought to exist does exist. We can, therefore, if this account be true, at least know what false opinion or error can be, whether or not we have any means of deciding in regard to any particular opinion that it is false. There is one other theory, the last we shall notice. It is in one respect the most important of all, namely, that it is the most direct attempt to grapple with the problem of error. It is founded on a theory of knowledge which we owe mainly to the profound and acute work of a German philosopher (Meinong), and which at the present time is being keenly discussed. It is an attempt to determine more exactly than has yet been done the fundamental scheme of the mental life and development. The brief account that I am now offering, I owe to a paper by Prof. G. F. Stout on "Some Fundamental Points in the Theory of Knowledge." We have seen that the problem of error is the difficulty there is in conceiving how there can be any real thing, any real {85} object of thought, intermediate between being and not-being. Error seems to exist and yet to have a nature which is a negation of existence, and it seems therefore to be a downright contradiction when we affirm that error or false opinion can _be_--that there is a real object of thought when we judge falsely. This theory meets the difficulty directly by distinguishing in the mental act of knowing a process that is neither perceiving nor thinking of things, and that involves neither believing nor disbelieving on the one hand nor desiring or willing on the other: this is the process of supposing. Corresponding to this mental act of supposing, there is a distinct kind of object intended or meant by the mind--an object that is neither a sense datum nor an idea, nor a judgment, but a supposition. Also and again corresponding to this mental act of supposing and its intended object the supposition, there is a mode of being which is neither existence nor non-existence, but is named subsistence. A supposition,