This question seems to pop up every once in a while and it is a puzzling one. But, I have been toying with an idea about it. I would suppose, a safe assumption to make is that knowledge starts with sense experience or in the very least, knowledge of the empirical starts with sense experience. So, if we work off of this assumption, I think that this idea of our senses being unreliable is an incoherent position, for surely you would have to have reliable senses in order to confirm that your senses aren't reliable (obviously, this is a contradiction) or else, how could you ever come to know it? This is a very premature idea, so I am wondering what you all think about it.