"Our five senses even interfere with sensible answers to stupid metaphysical questions like, "If a tree falls in the forest and nobody is around to hear it, does it make a sound?" My best answer is, "How do you know it fell?" But that just gets people angry. So I offer a senseless analogy, "Q: If you can't smell the carbon monoxide, then how do you know it's there? A: You drop dead." In modern times, if the sole measure of what's out there flows from your five senses then a precarious life awaits you."