As the title to his central work – Phenomenology of Perception – indicates, perceptual experience is a, if not the, central topic of MerleauPonty’s philosophy. The title indicates additionally that his approach to that topic is phenomenological. Merleau-Ponty insists that a phenomenology of perception is absolutely vital for arriving at an understanding of perception’s place in our overarching conception of ourselves and the world around us. Too often, he thinks, perceptual experience has been overlooked or mischaracterized so that its founding role has not been fully appreciated; too often, philosophers and scientists have tried to characterize perception in terms that are both descriptively inadequate and explanatorily inert. Such descriptions of experience tend to introduce notions – sensations, stimuli, judgements – that are not really present in our perceptual experience, and such explanations tend to appeal to processes that owe their sense to the prior workings of perception. Too often, in other words, the philosopher or the scientist describes perceptual experience “as one might describe the fauna of a distant land – without being aware that he himself perceives, that he is the perceiving subject and that perception as he lives it belies everything that he says of perception in general” (PP: 207). As a result, researchers do not fully appreciate that “all knowledge takes its place within the horizons opened up by perception”, and so that “there can be no question of describing perception itself as one of the facts thrown up in the world, since we can never fill up, in the picture of the world, that gap which we ourselves are, and by which it comes into existence for someone, since perception is the ‘flaw’ in this ‘great diamond’” (ibid.).