Evolution as Cyclical Repetition

If we lapse into thinking of the prebiotic, pre-reproductive world as a sort of featureless chaos of chemicals (like the scattered parts of the notorious jetliner assembled by a windstorm), the problem does look daunting and worse, but if we remind ourselves that the key process in evolution is cyclical repetition (of which genetic replication is just one highly refined and optimized instance), we can begin to see our way to turning the mystery into a puzzle: How did all those seasonal cycles, water cycles, geological cycles, and chemical cycles, spinning for millions of years, gradually accumulate the preconditions for giving birth to the biological cycles? Probably the first thousand “tries” were futile, near misses. But as the wonderfully sensual song by Gershwin and DeSylva reminds us, see what happens if you “Do it again” (and again, and again). A good rule of thumb, then, when confronting the apparent magic of the world of life and mind is: Look for the cycles that are doing all the hard work.

Daniel C. Dennett adds a cognitive tool to help understand how evolution works over time--by recognizing that evolution keeps trying, reproduction is a cycle.