Theory and fact are equally strong and utterly interdependent; one has no meaning without the other. We need theory to organize and interpret facts, even to know what we can or might observe. And we need facts to validate theories and give them substance.

Pictures are not incidental frills to a text; they are essences of our distinctive way of knowing.

Science is not a heartless pursuit of objective information; it is a creative human activity.

Objectivity cannot be equated with mental blankness; rather, objectivity resides in recognizing your preferences and then subjecting them to especially harsh scrutiny - and also in a willingness to revise or abandon your theories when the tests fail (as they usually do).

Facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts do not go away while scientists debate rival theories for explaining them. Einstein's theory of gravitation replaced Newton's, but apples did not suspend themselves in mid-air pending the outcome.

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

Evolution is one of the two or three most primally fascinating subjects in all the sciences.