We humans are obsessed with purpose. The question, “What is it for?” comes naturally to a species surrounded by tools, utensils and machines. For such artifacts it is appropriate, but then we go too far. We apply the “What is it for?” question to rocks, mountains, stars or the universe, where it has no place.
How about living things? Unlike rocks and mountains, animals and plants, wings and eyes, webbed feet and leaves, all present a powerful illusion of design. Since Darwin, we have understood that this, too, is an illusion. Nevertheless, it is such a powerful illusion that the language of purpose is almost irresistible. Huge numbers of people are seriously misled by it, and biologists in practice use it as a shorthand.
I shall develop two meanings of “purpose.” Archi-purpose is the ancient illusion of purpose, a pseudo-purpose fashioned by natural selection over billions of years. Neo-purpose is true, deliberate, intentional purpose, which is a product of brains. My thesis is that neo-purpose, or the capacity to set up deliberate purposes or goals, is itself a Darwinian adaptation with an archi-purpose.
Neo-purpose really comes into its own in the human brain, but brains capable of neo-purposes have been evolving for a long time. Rudiments of neo-purpose can even be seen in insects. In humans, the capacity to set up neo-purposes has evolved to such an extent that the original archi-purpose can be eclipsed and even reversed. The subversion of purpose can be a curse, but there is some reason to hope that it might become a blessing.
