Pinhole Archive 08/01/00 to 7/31/01: Asking Why

Hello Ron! Thank you for replying to my email; it's good to debate fundamental questions like these. I have to disagree with you about Aristotle, that it was impossible to ask why the natural order was what it is under his system. Aristotle linked his physical ideas with an elaborate "metaphysics" (Greek for "after the physics") and theology, that explained why the physical world had to be what it was. Aristotle's system involved a gorgeous vision of "a place for everything and everything in its place," with all things possessing their proper type of motion, ordered by a benevolent divinity, the "unmoved mover," who imparted just the right motions to all physical things. It was a beautiful view of the world that inspired Johannes Kepler, for example, to search for the "music of the spheres" and in so doing to lay the foundation for Newton's work. (A good feel for this world-view can be had enjoyably in C.S. Lewis' Perelandra science fiction trilogy.) Most importantly, it imparted to its partisans the subjective feeling that they understood why the world was as it is, and that it could not be any different. It explained why the natural order was what it was.

For me that's the eternal motive behind science, to wonder which things in the world have to be the way they are and which are arbitrary. Einstein, not an insignificant authority I hope, expressed it well as usual when he said, "the only question that really interests me is whether God had a choice in how He created the world."

My teachers in high school were not hacks, but good, intelligent and dedicated people. They ascribed, however, the same view of science as you express. I remember pestering my physics teacher in twelfth grade why gravity diminishes with the square of the distance. "That's just what experiments have shown," he would say. "But why is it that way," I would ask, "you can't just give us these equations to memorize without an explanation for them." "Well, that's science," he replied. I concluded that science was not a serious discipline; it systematically refused to go behind appearances and ask deep questions.

Too many years later, I was filled with delight from the top of my head to the tip of my toes during the summer teachers' institute when I saw the exhibit in the Exploratorium in which a lightbulb shines through a grid and reflects its shadow onto a background. It makes it intuitively obvious that any force that fills space is going to have to diminish as the square of the distance. It's more complicated than that, since some forces like the strong force don't obey that law, but on a basic level the explanation works. It's so exciting for a student to learn why something fundamental about the world has to be the way it is. Had my teacher given me that explanation in high school ... who knows what I might have become.

Another delightful explanation for me is that for magnetism. Electricity and magnetism obviously have a lot to do with each other, but what? One book Paul Dougherty showed me (also during that summer teachers' institute) showed two rods of iron going by each other at relativistic speed. They shrank relative to each other, and the electrical force contained in them had to go somewhere -- into magnetic lines of force surrounding the rods! Wow, so that's what magnetism is!

Another great pleasure during that same summer institute was the explanation for litmus paper. A basic environment has many more available electrons than an acidic one; these electrons fill holes in the molecules of the litmus paper and shorten the distance electrons can travel along them, changing the color from red (long wavelength) when dipped in acids to blue (short wavelength) in bases. This explanation connects colors with chemistry in a delightfully clear way, and gives a feeling for what acids and bases are. That's science teaching!

I think the goal of science is the same as it was in Aristotle's time, never to rest content until the appearance of things has been traced back, with rigorous logic, to ever more fundamental levels. In physics the fundamental concept is symmetry, which connects the operations of forces with topology and geometry; c-p-t symmetry throws new light on several seemingly unanswerable physical questions. Science should give us the same pleasure as Euclid's geometry, tightening the constraints as far as possible and showing that the world is not arbitrary, but has to be the way it is. Everything else is a means to this end.