There is a special equation in physics, which we have all heard of, \(E = mc^2\). I think of it as a gift to mankind. It’s a simple refutation of materialism. It shows that mass is none other than energy, which in Buddhist terms is “empty”. In other words energy is empty of solid boundaries, definition, or unchanging nature . It manifests as sound, form, heat, motion, light, and so forth. As Buddha said, “Form is emptiness, emptiness is form. Form and emptiness cannot be separated.” Einstein himself believed in the potential of Buddhism to be a modern religion. He said, “If there is one religion that would cope with modern scientific need, it would be Buddhism.”
I like to give this equation as an example of things being more free and empty than they appear, because even a child—who has probably heard this equation many times—can relate to it. One time, my friends and I were hosting a Buddhist teacher for a weekend program, and, at the end of the weekend, we celebrated by getting lunch at a nearby restaurant. His daughters were very intelligent and interested in science, so I shared with them the meaning of \(E = mc^2\), that even small amounts of matter contain massive quantities of energy. I said, “If you could release the energy in that salt shaker, it would blow up Texas!” To which, his younger daughter, about 7, replied, “Don’t do it!”
I felt that I was exaggerating, but assuming a salt shaker weighs 100g, releasing its energy would be 107 times more powerful than the bomb which was dropped on Nagasaki (which contained 84teraJoules of Energy), so perhaps I was not off by much.
Since the meaning of this equation can give an intuitive insight into the nature of reality, I thought it would be nice to have an as-intuitive-as-possible derivation of it for my own benefit and to share with you all. Watch out because the math starts here! If you’re satisfied with an interpretation of this equation, you can stop reading at this point. If knowing how to derive Einstein’s most famous equation gives you a feeling of confidence or ownership please continue.