[dpau]

you were of course correct, but your professor was simply illustrating a point- of whether we can trust our senses, of how we truly "know" something. philosophy often brings up "commonsensical" questions such as these. he probably didn't reply to you because he was bored from hearing the same smart alecky response every year :)

[dekhn]

If that was his point, there are far better ways to argue for it (specifically, Descartes' great deceiver). There was nothiing smart alecky about my response- just touching the stick, or pulling the stick back out, would verify that it was not broken.

[barry-cotter]

If he couldn’t illustrate his point without using an optical illusion explained by high school physics maybe he should be doing something else.