87. We have already seen how Locke, in his doctrine of secondary qualities of substances, practically gets over this difficulty; how he first projects out of the simple ideas, under relations which it requires a mind to constitute, a cognisable system of things, and then gives content and definiteness to the simple ideas in us by treating them as manifestations of this system of things. In the doctrine of propositions, the proper correlative to the reduction of the real to the present simple idea, as that of which we cannot get rid, would be the reduction of the ‘real proposition’ to the mere ‘it is now felt.’ If the matter-of-fact is to be that in consciousness which is independent of the ‘work of the mind’ in comparing and compounding, this is the only possible expression for it. It states the only possible ‘real essence,’ which yet is an essence of nothing, for any reference of it to a thing, if the thing is outside consciousness, is an impossibility; and if it is within consciousness, implies an ‘invention of the mind’ both in the creation of a thing, ‘always the same with itself,’ out of perishing feelings, and in the reference of the feelings to such a thing. Thus carried out, the antithesis between ‘fact’ and ‘creation of the mind’ becomes self-destructive, for, one feeling being as real as another, it leaves no room for that distinction between the real and fantastic, to the uncritical sense of which it owes its birth. To avoid this fusion of dream-land and the waking world, Locke avails himself of the distinction between the idea (_i.e._ feeling) as in the mind, which is not convertible with reality, and the idea as somewhere else, no one can say where--‘the actual sensation’--which is so convertible. The distinction, however, must either consist in degrees of liveliness, in which case there must be a corresponding infinity of degrees of reality or unreality, or else must presuppose a real existence from which the feeling, if ‘actual sensation,’ _is_--if merely ‘in the mind’ _is not_--derived. Such a real existence either is an object of consciousness, or is not. If it is not, no distinction between one kind of feeling and another can for consciousness be derived from it. If it is, then, granted the distinction between given feelings and creations of the mind, it must fall to the latter, and a ‘thing of the mind’ turns out to be the ground upon which ‘fact’ is opposed to ‘things of the mind.’ Two meanings of real essence.