32. Between these two meanings of existence--its meaning as interchangeable with simple consciousness, and its meaning as reality--Locke failed to distinguish. Just as, having announced ‘ideas’ to be the sole ‘materials of knowledge,’ he allows himself at his convenience to put ‘things’ in the place of ideas; so having identified existence with momentary consciousness or the simple idea, he substitutes for existence in this sense _reality_, and in consequence finds reality given solely in the simple idea. Thus when the conceptions of cause or substance, or relations of any kind, come under view, since these cannot be represented as given in momentary consciousness, they have to be pronounced not to exist, and since existence is reality, to be unreal or ‘fictions of the mind.’ But without these unreal relations there could be no knowledge, and if they are not given in the elements of knowledge, it is difficult to see how they are introduced, or to avoid the appearance of constructing knowledge out of the unknown. Given in the elements of knowledge, however, they cannot be, if these are simple ideas or momentary recurrences of the ‘it is felt.’ But by help of Locke’s equivocation between the two meanings of existence, they can be covertly introduced as the real. Existence is given in the simple idea, existence equals the real, therefore the real is given in the simple idea. But think or speak of the real as we will, we find that it exhibits itself as substance, as cause, and as related; _i.e._ according to Locke as a ‘complex’ or ‘invented’ or ‘superinduced’ idea. Yet reality involves complex ideas which are made by the mind.