Darwin’s Compass: Why the evolution of humans is inevitable

Orthodox neo-Darwinism very much emphasises the random and contingent. Re-run the tape of life, as Steven Jay Gould famously observed, and the outcomes would be utterly different. Terrestrial life maybe, but certainly no humans. They, like tulips and tape-worms, are just another evolutionary fluke. The basis of this is hardly surprising: think of random mutations, massive shifts in the environment, not to mention the odd giant rock dropping out of the sky. Life is on a roller-coaster and is flung from one strange place to another. Conway Morris argued for the exact reverse, that evolution is like any other science, that is it is predictable. The mainstay of this argument revolved around evolutionary convergence, the observation that from different starting points evolution arrives at the same solution. A classic example is the camera-eyes (and please do not mention ‘deep homology'), but less appreciated is that convergence is not common, it is ubiquitous. Evidence continues to grow that evolutionary bifurcations are far from random, but probably lead to inevitable outcomes. This suggests the Tree of Life is very different from the sprawling mass of foliage that is commonly envisaged. Also of great importance is the inherency of molecular systems and the capacity for self organisation. Darwinian evolution explains the mechanism, but not the outcomes.