The question of whether there are unconscious perceptions, and if so, their nature, has received considerable attention from philosophers and psychologists from the seventeenth century onwards. One's answer to this question will reveal a lot about one's conception of perception in particular and of the nature of the mind in general. Some care is needed in approaching the question. 'Perceive' is sometimes taken to mean 'be aware of', and if it is so taken, of course one cannot perceive anything unconciously, by definition. Such a definition doesn't, however, dispose of the question, for one can either stipulate that by 'perceive', one means to 'have a mental representation' (for now, let me just stipulate that a mental representation is an internal representation that enables one to have a sense-based perception: the nature and status of mental representations is a topic that deserves considerable attention in its own right): if one takes 'perceive' in this sense, then one can have both conscious and unconscious perceptions. On this picture, all perceptions are representations, some of which are conscious and some of which are not. (The question of why some perceptions make it to consciousness is another good one that merits further attention, but I bracket it here.) There are numerous examples of unconscious mental representations, I present just one. If one is driving along the road, thinking about the question of whether there are unconscious perceptions, one may not be consciously attending to the road, but, nevertheless, one continues to follow the road, and to adjust one's driving to the road, and even, if something appears suddenly on the road, one may respond to it, even though one's attention is not focused on the road. It seems to me that one plausible explanation of this phenomenon--not the only explanation, to be sure--is to posit unconscious representations of the road. This is the sort of everyday phenomenon that provides good reason, I think, to hold that it is possible to perceive something unconsciously.
Read another response by Sean Greenberg
Is it possible to perceive something unconsciously?