It's because somebody knows something about it that we can't talk about physics. It's the things that nobody knows anything about we can discuss.

There are 10^11 stars in the galaxy. That used to be a huge number. But it's only a hundred billion. It's less than the national deficit! We used to call them astronomical numbers. Now we should call them economical numbers.

People may come along and argue philosophically that they like one better than another; but we have learned from much experience that all philosophical intuitions about what nature is going to do fail.

To not know math is a severe limitation to understanding the world.

If you don't like it, go somewhere else, to another universe where the rules are simpler.

Thus we can get the correct answer for the probability of partial reflection by imagining (falsely) that all reflection comes from only the front and back surfaces. In this intuitively easy analysis, the 'front surface' and 'back surface' arrows are mathematical constructions that give us the right answer, whereas .... a more accurate representation of what is really going on: partial reflection is the scattering of light by electrons inside the glass.

I think Nature's imagination is so much greater than man's, she's never gonna let us relax!