Enlightenment Now: The Case for Reason, Science, Humanism, and Progress

Why the awe for the Second Law? From an Olympian vantage point, it defines the fate of the universe and the ultimate purpose of life, mind, and human striving: to deploy energy and knowledge to fight back the tide of entropy and carve out refuges of beneficial order. From a terrestrial vantage point we can get more specific, but before we get to familiar ground I need to lay out the other two foundational ideas.

At first glance the Law of Entropy would seem to allow for only a discouraging history and a depressing future. The universe began in a state of low entropy, the Big Bang, with its unfathomably dense concentration of energy. From there everything went downhill, with the universe dispersing—as it will continue to do—into a thin gruel of particles evenly and sparsely distributed through space. In reality, of course, the universe as we find it is not a featureless gruel. It is enlivened with galaxies, planets, mountains, clouds, snowflakes, and an efflorescence of flora and fauna, including us.

One reason the cosmos is filled with so much interesting stuff is a set of processes called self-organization, which allow circumscribed zones of order to emerge.⁵ When energy is poured into a system, and the system dissipates that energy in its slide toward entropy, it can become poised in an orderly, indeed beautiful, configuration—a sphere, spiral, starburst, whirlpool, ripple, crystal, or fractal. The fact that we find these configurations beautiful, incidentally, suggests that beauty may not just be in the eye of the beholder. The brain’s aesthetic response may be a receptiveness to the counter-entropic patterns that can spring forth from nature.

But there is another kind of orderliness in nature that also must be explained: not the elegant symmetries and rhythms in the physical world, but the functional design in the living world. Living things are made of organs that have heterogeneous parts which are uncannily shaped and arranged to do things that keep the organism alive (that is, continuing to absorb energy to resist entropy).⁶

The customary illustration of biological design is the eye, but I will make the point with my second-favorite sense organ. The human ear contains an elastic drumhead that vibrates in response to the slightest puff of air, a bony lever that multiplies the vibration’s force, a piston that impresses the vibration into the fluid in a long tunnel (conveniently coiled to fit inside the wall of the skull), a tapering membrane that runs down the length of the tunnel and physically separates the waveform into its harmonics, and an array of cells with tiny hairs that are flexed back and forth by the vibrating membrane, sending a train of electrical impulses to the brain. It is impossible to explain why these membranes and bones and fluids and hairs are arranged in that improbable way without noting that this configuration allows the brain to register patterned sound. Even the fleshy outer ear—asymmetrical top to bottom and front to back, and crinkled with ridges and valleys—is shaped in a way that sculpts the incoming sound to inform the brain whether the soundmaker is above or below, in front or behind.

Organisms are replete with improbable configurations of flesh like eyes, ears, hearts, and stomachs which cry out for an explanation. Before Charles Darwin and Alfred Russel Wallace provided one in 1859, it was reasonable to think they were the handiwork of a divine designer—one of the reasons, I suspect, that so many Enlightenment thinkers were deists rather than outright atheists. Darwin and Wallace made the designer unnecessary. Once self-organizing processes of physics and chemistry gave rise to a configuration of matter that could replicate itself, the copies would make copies, which would make copies of the copies, and so on, in an exponential explosion. The replicating systems would compete for the material to make their copies and the energy to power the replication. Since no copying process is perfect—the Law of Entropy sees to that—errors will crop up, and though most of these mutations will degrade the replicator (entropy again), occasionally dumb luck will throw one up that’s more effective at replicating, and its descendants will swamp the competition. As copying errors that enhance stability and replication accumulate over the generations, the replicating system—we call it an organism—will appear to have been engineered for survival and reproduction in the future, though it only preserved the copying errors that led to survival and reproduction in the past.