ABSTRACT
A thing has ‘characteristics’ or ‘properties’ which are stable, even if they do not entirely serve to define it, and we propose to approach the phenomenon of reality by studying perceptual constants. A thing has in the first place its size and its shape throughout variations of perspective which are merely apparent. We do not attribute these appearances to the object itself, but regard them as an accidental feature of our relations with it, and not as being of it. What do we mean by this, and on what basis do we judge that form or size are the form and size of the object?
