Morning Scepticism: Why

It's been said in attempts to make science and religion distinct that science explains the how and religion explains the why, but I would content that for a lot of why questions it would be incoherent to ask religion and unrepresentative if they weren't scientific. A simple illustration is sight. To ask "how do we see?" is perfectly accepted in the realm of science, but "why do we see?" will inevitably misrepresent if not grounded in science. To rubbish the why question or resign it to religion would guarantee that the answer won't be of value. It's not to say that all why questions are scientific, but that the distinction between different kinds of inquiry is not so clear.