21. And it does not by any means follow, in that case, that the simple substance is without perception: that, indeed, is impossible, for the reasons given above; for it cannot perish, neither can it subsist without affection of some kind, which is nothing else than its perception. But where there is a great number of minute perceptions, and where nothing is distinct, one is stunned, as when we turn round and round in continual succession in the same direction; whence arises a vertigo, which may cause us to faint, and which prevents us from distinguishing anything. And possibly death may produce this state for a time in animals. 22. And as every present condition of a simple substance is a natural consequence of its antecedent condition, so its present is big with its future. 23. Then, as on awaking from a state of stupor, we become conscious of our perceptions, we must have had perceptions, although unconscious of them, immediately before awaking. For each perception can have no other natural origin but an antecedent perception, as every motion must be derived from one which preceded it. 24. Thus it appears that if there were no distinction—no relief, so to speak—no enhanced flavor in our perceptions, we should continue forever in a state of stupor; and this is the condition of the naked Monad. 25. And so we see that nature has given to animals enhanced perceptions, by the care which she has taken to furnish them with organs which collect many rays of light and many undulations of air, increasing their efficacy by their union. There is something approaching to this in odor, in taste, in touch, and perhaps in a multitude of other senses of which we have no knowledge. I shall presently explain how that which passes in the soul represents that which takes place in the organs. 26. Memory gives to the soul a kind of consecutive action which imitates reason, but must be distinguished from it. We observe that animals, having a perception of something which strikes them, and of which they have previously had a similar perception, expect, through the representation of their memory, the recurrence of that which was associated with it in their previous perception, and incline to the same feelings which they then had. For example, when we show dogs the cane, they remember the pain which it caused them, and whine and run. 27. And the lively imagination, which strikes and excites them, arises from the magnitude or the multitude of their previous perceptions. For often a powerful impression produces suddenly the effect of long habit, or of moderate perceptions often repeated.