Friday, July 15, 2016
Explanation and Teleology 2
Teleological explanations are appropriate when some process can be understood only by the end at which it aims. Such a process necessarily involves the possibilities of success or failure: the end may be achieved or not. The most obvious examples are those of human production. A farmer plants seeds in order to produce a crop. It may rain just enough, or too little or too much.
Yet much the same thing seems to be true of the seed itself. It sprouts and the sapling breaks the soil. It is obviously trying to do something, to reach the sun. If it is strong and conditions are favorable, it will flourish; if not, it will wither and die.
The great philosopher of biology, Ernst Mayr drew a distinction between teleomatic and teleonomic processes. As an example of the former, drop a stone into a well. The beginning predetermines the end. The stone will end up on the bottom. That doesn’t mean that the stone is trying to get there. Its irregular course is entirely determined by its weight and shape and the accidents of the water. That is a teleomatic process.
The growth of a plant is very different. Consider a vine growing up a wall. If you watched it in stop motion you would see that it is very deliberately climbing. It twists around this way and that looking for a purchase. When it finds one, it takes hold and climbs again. The vine has a program that determines its action. The program directs it toward something: the sun, perhaps. That is a teleonomic process.
Is it possible that we are only anthropomorphizing? Perhaps we are only projecting our own purpose driven actions back onto nature, as when people think that the volcano blew its top because the gods are angry. Here is a counter example: years ago when I walked up to campus I noticed snowflakes falling on my arm. They were perfect little six point stars made of two intersecting triangles. I paused to wonder if God were telling me something. The Jews are right!
Maybe they are. About a lot of things. I think, though, that the “program” that determined the form of the snowflake was nothing other than the structure of the water molecules behaving according to the circumstances. That is a teleomatic process, nothing more. How then does the climbing vine differ? It too takes form according to the complex molecules that it inherited.
Here evolutionary theory kicks in. Snowflakes do not give birth to other snowflakes. The production of a six pointed star on a winter day does not result in a lineage of six pointed crystal stars with parents and grandparents. By contrast, the vine has parents and will, if it is successful, have offspring. Without understanding that, you cannot understand what a vine is.
I suspect that the lineage is an essential element in the definition of life. If this were all there were to it, teleological explanations would be reduced to the successful extension of biological lineages. That may indeed be true of most of the organisms on our world. However…
At some point evolution produced sentient organisms. This kind of creature can respond to its environment in a much more flexible way than vines. It has a robust kind of freedom: it can move this way or that, snatch or flee. Natural selection favored those creatures that acted in ways that promoted successful reproduction. Since they had an element of freedom, it had to work by bribing them with pleasure and punishing them with pain. These existential elements function to select behaviors that promote successful reproduction without paying the cost of death.
Now we have a telos that is distinct from the simple evolutionary telos. A plant either flourishes or withers. Its only rewards are saplings; its only punishment, no saplings. An animal can flourish and yet be miserable. Animals act for the sake of what pleases them and to avoid what displeases them. They have an existential stake in their lives.
Human beings represent the most advanced stage of this evolutionary trajectory. Whereas all the other animals can tell the difference between what they like and what they do not like, human beings alone can distinguish between what they like and what is really good for them. This capacity is amazing, but not without robust biological roots. It arises out of a capacity for building internal, mental models of the external world. This feature of animal life is ubiquitous.
There is a species of spider that makes its living by feeding on other spiders. To hunt it climbs high by spider standards among leaves, or at least high by spider standards, and looks out for prey. In order to attack its prey safely, it has to come up behind it. To do that, it has to climb back down to the floor and climb up again in a route that will allow it to come up in a strategically favorable position. To do that, it has to build a map of the general route.
Internal mapping of the external environment is a very profitable strategy. Very simple organisms have to try the same trick every time and live or die depending on whether it works this time. More complex organisms can try different tricks, but only find out what works by testing it in perilous conditions. Creatures capable of internal mapping can try it first in the safe environment of the map, thus avoiding a lot of dangers and saving precious energy.
Anthropoi are, if nothing else, very sophisticated internal mappers. It is one reason that we spend some much of our time living in our own imaginations. It allows us to build pyramids and send probes to see whether the planet Jupiter has a solid core or not. It also allows us to choose not to eat a big bag of pork rinds even though we would really enjoy that. The moral dimension emerges when we began to distinguish between what we want to do and what we ought to do. That, almost certainly, was a product of our evolution as political animals. We became very effective cooperators because we were able to resist the temptation to cheat one another, more or less, enough for government work. Our mapping software includes a lot of prepackaged apps for getting along with other people, for demonstrating that we are good partners, for detecting when someone else is not.
Teleological explanations applied to human technology and those directed toward biological phenomena are in one sense the same and in another different. They are the same in the sense that they emerge in evolutionary history due to the same dynamics. We learned how to build dwellings for the same reason that ants and bees did: to survive. They are not the same in the sense that we are pursuing ends that are not reducible to mere biological lineages. Like any other animal, we pursue comfort and satisfaction directly and serve our Darwinian interests only indirectly. Unlike any other animal, we are capable of genuine happiness. We can achieve a life that is consciously satisfying, in a broad awareness of who we are and what we want.
It was long assumed that Aristotle was illegitimately anthropomorphizing when he introduced teleological explanations to his science of nature. Darwinian biology shows that he was legitimately anthropomorphizing. Because human powers of thought are the products of evolutionary history, they are the best information we have about evolutionary history.