The problem with the senses is the “relativity of perception.” Aristotle cites the contrariness of the sense-perceptions of different persons (the same food being thought sweet by some and bitter by others, for example), of animals other than ourselves, and even of the same person in different situations.
<quote>Which, then, of these impressions are true and which are false is not obvious; for the one set is no more true than the other, but both are alike. And this is why Democritus, at any rate, says that either there is no truth or to us at least it is not evident.” (Metaphysics, Book IV, Chapter 5)</quote>
<a href=”http://hume.ucdavis.edu/mattey/phi143/epiepi.htm”> Philosophy 143 Lecture Notes: Epicurean Epistemology</a>
It has always been recognized that many uses of the faculty of sense are subject to error. The sun looks like a body about the size of a dime, and it appears to move around the earth. We have images that we take to be of things before us, but nothing like it is there. Still, a defender of the senses will point out that these are errors in the details about the objects of the senses. How can one doubt the very modest claim that there are external objects corresponding to our sense images?
<a href=”http://hume.ucdavis.edu/mattey/phi001/desclec.htm”> 1994 Lecture Notes: René Descartes</a>