Forelimbs of people, porpoises, bats and horses provide the classic example of homology in most textbooks. They look different, and do different things, but are built of the same bones. No engineer, starting from scratch each time, would have built such disparate structures from the same parts.

The human mind delights in finding pattern—so much so that we often mistake coincidence or forced analogy for profound meaning. No other habit of thought lies so deeply within the soul of a small creature trying to make sense of a complex world not constructed for it.

The history of life is more adequately represented by a picture of 'punctuated equilibria' than by the notion of phyletic gradualism. The history of evolution is not one of stately unfolding, but a story of homeostatic equilibria, disturbed only 'rarely' (i.e. rather often in the fullness of time) by rapid and episodic events of speciation.

Evolution is a process of constant branching and expansion.

Look in the mirror, and don't be tempted to equate transient domination with either intrinsic superiority or prospects for extended survival.

People are clever, but almost no one ever devises an optimal quip precisely at the needed moment. Therefore, virtually all great one-liners are later inventions - words that people wished they had spouted, but failed to manufacture at the truly opportune instant.

The dogmatist within is always worse than the enemy without.