I have been reading DM Armstrong’s book “Perception and the Physical World’, in which he proffers a defence of direct realism, based on a definition of perception as the acquiring of knowledge, or the inclination to believe, particular facts about the physical world by means of the senses. On the whole I found his thesis unconvincing, due to the insufficient attention paid to the phenomenal feel of sensations and to neurophysiology (which is understandable considering the book was written more than 40 years ago).