in particular that it has no perceptions during dreamless sleep, arguing that since bodies can be without movement souls can just as well be without thought. But my response to this is a little different from the usual one. For I maintain that in the natural course of things no substance can lack activity, and indeed that there is never a body without movement. Experience is already on my side?and to be convinced one need only consult the distinguished Mr #Boyles book attacking absolute rest. But I believe that reason also supports this, and that is one of my proofs that there are no atoms. Besides, there are hundreds of indications leading us to conclude that at every moment there is in us an infinity of perceptions, unaccompanied by ^awareness or reflection; that is, of alterations in the 6oul itself, of which we are unaware because these impressions are either too minute and too numerous?or else too unvarying?so that they are not sufficiently distinctive on their own. But when they are combined with others they do nevertheless have their effect and make themselves felt, at least confusedly?within the whole. This is how we become so accustomed to the motion of a mill or a waterfall, after living beside it for a while?that we pay no heed to it Not that this motion ceases to strike on our sense-organs?or that something corresponding to it does not still occur in the soul because of the harmony between the soul and the body; but these impressions in the soul and the body, lacking the appeal of novelty, are not forceful enough to attract our attention and our memory, which are applied only to more compelling objects. Memory is needed for attention: when we are not alerted, so to speak, to pay heed to certain of our own present perceptions, we allow them to slip by unconsidered and even unnoticed. But if someone alerts us to them straight away, and makes us take note?for instance, of some noise which we have just heard, then we remember it and are aware of just having had some sense of it. Thus, we were not straight away aware of these perceptions, and we became aware of them only because we were alerted to them after an interval, however brief. To give a clearer idea of these minute perceptions which we are unable to pick out from the crowd, I like to use the example of the roaring noise of the sea which impresses itself on us when we are standing on the shore. To hear this noise as we do, we must hear the parts which make up this whole that is the