Nothing would be simpler than to class all these phenomena offhand as optical illusions, than to say that since we see motion where, “in reality,” nothing moves, it can only be a matter of our being deceived by our senses. One may adopt this standpoint—if one wants at all costs to block the road to understanding these things. Certainly one can say it is an illusion when a stick held under water looks bent at the surface; but to say this is only to say something about oneself, about our own narrow perspective which, out of the whole universe, sees nothing, can see nothing, but the stick; which is unable to conceive that such an image might relate to something else, might contain a statement about something other than the stick. The stick is straight, so the image of it as bent must be an illusion. The image is dumb, it can only present itself; if we attribute false statements to it, something that it does not mean, and then accuse it of leading us astray, it can only persist and wait until we arrive at understanding. Today we know that the image did not refer to the stick but to light; did not want to make a statement about the stick but about the bending of light when it passes from air into water. How long did it not take for us to understand what the eye, in its wonderfully clear and simple way, had since time immemorial been presenting for our understanding! But what do we, with our incorrigible stick-mindedness, do? We boast of what our intellect has accomplished and go on calling the image an illusion.
Victor Zuckerkandl, Sound and Symbol: Music and the External World, translated by Willard R. Trask