Showing posts with label lineage. Show all posts
Showing posts with label lineage. Show all posts

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.  

Friday, August 29, 2014

Living Organisms, Autonomy, & Lineages



Miranda: you are better than any student I have ever known at seeing what the next question is.  That is the single most important element in philosophy. 
Aristotle considered metabolism (the ability of a living organism to nourish itself and consequently produce waste) as a sufficient condition for life.  He referred to this as "nutritive soul."  Plants have this alone, whereas animals have additional layers (mobility, perception at a distance) and human beings have still others.  These are the elements that define various levels of autonomy.  I don't think that this makes autonomy just another word for life.  The word life points to what we are trying to understand whereas the word autonomy helps us to understand what life is. 
However, I smuggled in an element that does not seem to belong to autonomy so much: the production of babies.  Some philosophers of biology argue that, in addition to autonomy, living organisms have to be part of a lineage.  Every living organism is the offspring of a line of successful replicators. 
I am not certain, but I think that the addition of the lineage as an essential element of life is an attempt to head off the kind of objection that Scott James raises against me.  A political community, for example, seems to display autonomy or something very close to it.  It seems to struggle to maintain itself and it has to feed and produce waste.  Aristotle himself argued that the political community is precisely that human association that works enough dynamic cycles that it is "self-sufficient".  Well, if political communities are self-sufficient are they not autonomous?  And if they are autonomous, are they not alive? 
I think that the self-sufficient human community is a much stronger challenge to my view of autonomy than are refrigerators or thermostats.  It is tempting to talk about the evolution of political institutions and to see, for example, the United States as, perhaps, an example of political speciation.  The American regime broke off from the British regime in much the same way as homosapiens broke off from the common ancestor with pan troglodyte. 
This is misleading.  Political communities do not form lineages.  The Second Continental Congress formed spontaneously, as relations between the continent and the mother country worsened; it had no mommy or daddy.  Regimes form spontaneously all the time.  By contrast, living organisms do not form spontaneously.  They always have at least one biological parent. 
It is a very interesting question (and one that did not occur to me until your latest comment) whether the biological lineage is an element of life distinct from autonomy or whether it is another element of autonomy.  The cells and organs of my body (with the exception of my reproductive organs) have sacrificed any opportunity to reproduce.  Like sterile castes among the ants, they can have offspring only through the reproductive activity of something else (my gonads in the one case, the queen in the other).  Does this compromise their autonomy?  Every cell in my body is robustly alive as is the sister forager feeding on my picnic lunch.  I will have to ponder this one.