"In regard to all sense-perception generally we must understand that a sense
(sense-organ) is that which is able to receive perceptible forms of things
apart from their matter, as wax receives the imprint of the signet ring apart
from the iron or gold of which it is made:  it takes the imprint which is of
gold or bronze but not <i>qua</i> gold or bronze.  And, in similar fashion, in
each case, the sense (sense-organ) is acted upon by that which possesses
colour, flavour or sound, not in so far as each of these things is called a
particular thing, but in so far as it is a certain sort of thing and in
accordance with its account."<p>
<p>
	(<i>De Anima</i>, II, 12, 424a 17 ff)<p>