8.6. Okay, But What Is It…Really?

Energy is a sophisticated and abstract thing in physics. In fact, it’s not a “thing” at all. It’s not a substance. It’s a concept that behaves mathematically in particular ways…and manifests itself physically in different guises. It’s not surprising that it took more than three centuries to sort all of this out. We now know how to measure energy-guises. But, boy, what a mess for a long time.

Diamonds are Forever Energy as an abstraction is “just there.” About the best analogy (but not a perfect one) is with the idea of economic value. Is the value of an object, or currency, a “thing”? No, it’s a numerical concept which takes different guises and amounts which can at any point in a transaction be assigned a “value.” Economic value is economic energy. Take a rough diamond. By itself, it has a value (unfortunately one which often leads to violence and brutality) which is inherent: it can be traded with other objects which also have an equivalent value…like cash. In such a trade – a transaction – the total value of the two has not changed, just exchanged hands and in the process, changed kind. If you had diamonds, now you have cash. But you possess the same value. But, suppose the diamond is cut and polished. Labor – which has a value – has been added and in turn the value of the diamond has increased and an exchange for cash would require more. But the total value of the labor, the raw diamond, and the cash has not changed…just shifted. The total value-amount at the beginning (the raw diamond plus the potential value of the labor before it’s actually expended) is the same as at the end (the cash) but the potential value of the labor has been expended on transforming the diamond and adding to its value. All the while, this abstract quantity “value” has moved back and forth among the objects – exchanged hands, manifesting itself in various guises, but never actually standing alone as a substance.

Keep that in mind as we think about energy.

It's okay to be a little uneasy since energy is strange: simultaneously an easy idea and at the same time a complicated and even subtle idea. You'll see.