Teleology is an Aristotelean and medieval scholastic term meaning “purpose.” In its simplest form, teleology is easily demonstrated by example: the purpose of a plow is to plow the soil; the purpose of a spoon is for eating one’s soup, and so forth. The uncontroversial premise in these mundane examples is that these objects were fashioned by human beings (technology) for their desired purpose.

The premise shifts, however, when purpose is ascribed to mere facticity. For example, petroleum exists to fuel our machines. Here purpose is contrived from creative scientific human effort, in short, technology — or from mere utility, desire, and convenience. Our technology can sound useful and benign, and hence the purpose remains more or less uncontroversial. As long as the results are equally benign — something that only time reveals.

We make these ascriptions all the time and without problem, even when we realize that they are not strictly true. A butterfly flits by in order to give pleasure to our eyes and a bird sings in order to please our ears. We carve nature into useful and less useful, by which criteria we mean purposeful or less purposeful. The purposeness can betray us, of course, as in the instinctive repulsion at a caterpillar without realizing that it is the butterfly that will soon delight our eyes. If we destroy the caterpillar out of repulsion we destroy the opportunity to ascribe purpose to the entire cycle. This is what we do when we destroy a rain forest and its many plant and animal species, only to wonder at the laboratory’s latest synthesis of a healing herb.

Or rather, that is purpose put at a scientific level. For my part, I would want to anticipate the resourcefulness and beauty of everything, making it an ethical concern, and not having to calculate the utility that can never be exhaustive of every parameter. But that gets ahead of the issues.

The scale or depth of teleological complexities rise around us inexorably like a tide. Do the objects of our lives take on purpose or do we serendipitously ascribe purpose and therefore sentiment, attachment, and affection? It is not that the butterfly exists for our enjoyment, anymore than the petroleum in the ground for our convenience. Rather, we experience what things do, through observation or experimentation, and then cannot see them with neutral eyes. Even as we destroy them in our shortsightedness.

Sigmund Freud, whatever his excesses in psychoanalytical theory, wisely believed that existence was buffeted by two polarizing purposes, those of Eros (creativity, self-identification, potential) and Thanatos (aggression, destruction, violence, death). This Manichean scheme seems simplistic, but nevertheless forms the basis of all Western thinking, however configured. Regardless of how much good we assign to existence (to teleology), everything seems undermined by its opposite, whether we call this opposite sin or evil or fate or nature.

Practical examples always crystallize this problem of purpose. Remember the story of the child whose beloved pet has died? “Will I see my dog in heaven?” asks the child. What to reply? “Whatever made you happy on earth will make you happy in heaven” is all that parents or adults can respond. The child’s question, more profound than the adult’s dogmas, forces the question of teleology and collapses the belief-edifice of the adult into ignorance.

In childhood we become aware of purpose, especially in loss: the death of a butterfly or bird or pet animal, let alone in an elderly relative or someone even closer. Early childhood is the state of not-consciousness, which is to say the state of not demanding purpose (yet), that state of simply being. But this state does not last long. Dissipating, we are left with the awareness of mortality and the “knowledge of good and evil.” And we are never the same again. Purpose pales before existence and experience.

I am a little startled to read (though I guess I knew it) that butterflies live for a week or a month. What I see in the garden, so delighting my eyes, will soon be gone. The mournful chirp of the crickets in autumn reminded the Chinese and Japanese hermit poets of mortality. The purpose we assign to the butterfly, to please us, like the flowers and the birds and the pet animals and the forests, mountains, stars– and other people — also remind us of our mortality. Unlike the Roman emperor riding proudly in the chariot of his victory parade, we do not need a servant beside us to whisper in our ear: Remember that you are mortal. All of nature reminds us in its wistful and melancholic way.

We can enjoy the dark humor that pokes fun at this our weakest sentiment, this drollness that arises from the inadequacy of purpose, of humanly contrived teleology. Remember that popular saying intended to lift us out of the doldrums after making a big blunder or falling into a mood of depression? “Today is the first day of the rest of your life.” I admit the wicked humor of that wag who rewrote the saying for the mayfly, the insect that lives for only 24 hours: “Today is the last day of the rest of your life.”

Actually, if we lived by that motto, we might find ourselves fiercely attached to the beautiful and the wistful in life without demanding for one moment anything from them.