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

by Brian Greene

Now, to power its thinking, the Thinker must extract energy from its surroundings. And because heat is itself a form of energy, the amount of energy the Thinker takes in must be at least as large as the amount of heat the Thinker needs to expel. The input energy has higher quality (so it can be readily harnessed by the Thinker) than the output heat (which is waste and will thus be dispersed), but the Thinker can’t release more than it absorbs. So Dyson’s calculation specifies the minimum high-quality energy the Thinker needs to absorb from the environment, thereby quantifying the challenge: as stars burn out, solar systems unravel, galaxies disperse, matter disintegrates, and the universe expands and cools, the Thinker will face the increasingly difficult task of gathering the concentrated, high-quality, low-entropy energy it needs to continue cogitating. With provisions becoming scarce, the Thinker needs an effective strategy of resource management and waste disposal—a detailed plan, that is, for taking in low-entropy energy and flushing out high-entropy heat. Following Dyson, let’s come up with one.