Objective thought is unaware of the subject of perception. This is because it takes the world as ready-made or as the milieu of every possible event and treats perception as one of these events. The empiricist philosopher, for example, considers subject X while perceiving and attempts to describe what happens: there are sensations, which are the subject's states or manners of being and, as such, they are genuinely mental things. The perceiving subject is the place of these things, and the philosopher describes sensations and their substratum – as one might describe the fauna of a distant land – without noticing that he himself also perceives, that he is a perceiving subject, and that perception such as he lives it denies everything that he says about perception in general. For, seen from within, perception owes nothing to what we otherwise know about the world, about stimuli such as described by physics, and about sense organs as described by biology. It is not primarily presented as an event in the world to which the category of “causality,” for instance, might be applied, but rather as a recreation or a reconstitution of the world at each moment. If we believe in the world's past, in the physical world, in “stimuli,” and in the organism such as it is represented by textbooks, this is first of all because we have a present and real perceptual 215field, a surface of contact with the world or a perpetual rooting in it; it is because the world ceaselessly bombards and besieges subjectivity just as waves surround a shipwreck on the beach. All knowledge is established within the horizons opened up by perception. Since perception is the “flaw” in this “great diamond,”1 there can be no question of describing it as one of the facts that happens in the world, for the picture of the world will always include this lacuna that we are and by which the world itself comes to exist for someone.