Until the End of Time: Mind, Matter, and Our Search for Meaning in an Evolving Universe

by Brian Greene

Consider, as an example, a stick of dynamite. Because all the energy stored in the dynamite is contained in a tight, compact, orderly chemical package, the energy is easy to harness. Place the dynamite where you want its energy deposited and light the fuse. That’s it. Post-explosion, all of the dynamite’s energy still exists. That’s the first law in action. But because the dynamite’s energy has been transformed into the rapid and chaotic motion of widely dispersed particles, harnessing the energy is now extremely difficult. So, although the total amount of energy doesn’t change, the character of the energy does. Before the explosion, we say that the dynamite’s energy is high quality: it’s concentrated and easy to access. After the explosion, we say that the energy is low quality: it’s spread out and difficult to utilize. And since the exploding dynamite fully abides by the second law, going from order to disorder—from low entropy to high entropy—we associate low entropy with high-quality energy and high entropy with low-quality energy. Yes, I know. It’s a lot of highs and lows to keep track of. But the conclusion is pithy: whereas the first law of thermodynamics declares that the quantity of energy is conserved over time, the second law declares that the quality of that energy deteriorates over time. Why then is the future different from the past? The answer, apparent from what we’ve now developed, is that the energy powering the future is of lower quality than that poweri...