psychologist J. J. Gibson’s (1979) concept of affordances: “What the environment offers the animal for good or ill.” Affordances are the relevant opportunities in the environment of any organism: things to eat or mate with, openings to walk through or look out of, holes to hide in, things to stand on, and so forth.

creationists ask, rhetorically, “where does all the information in the DNA come from?” and Darwin’s answer is simple: it comes from the gradual, purposeless, nonmiraculous transformation of noise into signal, over billions of years.

Next come the Skinnerian creatures, who have, in addition to their hard-wired dispositions, the key disposition to adjust their behavior in reaction to “reinforcement”; they more or less randomly generate new behaviors to test in the world; those that get reinforced (with positive reward or by the removal of an aversive stimulus—pain or hunger, for

Intelligent design of this sort starts with a goal (which may well be refined or even abandoned along the way) and works top-down, with the designers using everything they know to guide their search for solutions to the design problems (and sub-problems, and sub-sub-problems …) they set for themselves. Evolution, in contrast, has no goals, no

When you can’t get her name out of your mind, is it always capitalized, or pronounced with a sigh?

Evolution by natural selection is not itself a designed thing, an agent with purposes, but it acts as if it were (it occupies the role vacated by the Intelligent Designer): it is a set of processes that “find” and “track” reasons for things to be arranged one way rather than another. The chief difference between the reasons found by evolution and

When you program, it is wise to add comments for yourself as you go, since you may easily forget what you thought the line of code was doing. When you go back to correct programming errors, these comments are very useful.

Evolution by natural selection starts with how come and arrives at what for.

To summarize, animals, plants, and even microorganisms are equipped with competences that permit them to deal appropriately with the affordances of their environments. There are free-floating rationales for all these competences, but the organisms need not appreciate or comprehend them to benefit from them, nor do they need to be conscious of them.