Reply to Bonnie on Evolutionary Explanations

Bonnie’s recent comment involved more than the topic of the last post.  To provide the context for the rest of the comment, my friend Ron posted this:

The problem with all teleological explanations is that many natural phenomena pursue multiple purposes. Although the "purpose" of the human eye is to see... we all look at each other's eyes to form judgments about personality... especially reproductive judgments. The Roman Catholic Church is especially intent on assigning reproductive purpose to monogamous marriage while ignoring friendship as a goal. THUS the question of whether one purpose is more "ultimate" than another purpose is often contingent upon contextual considerations.

This was in response to my recent post explanation and teleology2. I replied as follows:

If by ultimate we have in mind the proximate/ultimate distinction, it seems easy to sort out in case of eyes. Their ultimate function is clearly vision. This is powerfully reinforced by the observation that eyes are temporally and genetically prior to human eyes. Our ancestors had eyes long before the human species emerged.

That we have large whites around our corneas may be an adaptation. It allows us to tell when we are looking into one another's eyes and so facilitates communication. Since chimpanzees don't have such eyes, it is very probably a recent adaptation as runaway selection for intelligence and cooperation shaped our species. At any rate, it seems quite easy to assign these various features to primary and secondary functions.

I won't speak for the Catholics, but Aristotle (who has some purchase with them) also recognized reproduction as the primary function of marriage. This seems to me to be obviously true. It doesn't obviate (in fact it may comprehend) the function of friendship.

Bonnie in turn as this:

On eyes the ultimate (why) final cause of eye as vision could include seeing material objects and forms in the world. If one has an affinity with the poetic understanding of eyes as windows to the soul there are other questions. The ultimate evolutionary purpose of the white of eyes as an adaptive mechanism is purely speculative theory unless tested by scientific method. The science that studies sight at the most refined level is neuroscience.

I reply that the final cause of eyes as vision devices obviously includes seeing material objects and forms in the world.  Cats are looking for prey and prey are looking about for cats.  To test this, I need merely observe the cats and rabbits in my back yard.  The cat moves very slowly, because sudden movement is more visible to rabbits.  The rabbit responds to the cat by freezing, because movement is more visible to cats.  I am sure that the eyes of cats and rabbits are windows to their souls.  Most of what their souls are about is eating and not being eaten. 

What happens in human beings is a lot more poetic, I suspect; but then I am not a rabbit.  When I look at a painting by Joseph Turner, I am not trying to survive or mate.  I am pursuing beauty, which my evolutionary heritage has allowed me to pursue because all the necessary things have been provided.  My agenda is not the same as the agenda of my genes.  Much the same thing is happening when I watch the rabbits play with one another.  They leap at each other and seem to dance.  This may have some adaptive function, but it looks like simple fun.  A cat toying with a mouse is another example.  Good training for hunting, most likely; but a lot more fun for the one than the other. 

Yes, it is speculative that the large whites of human eyes may function to facilitate communication.  It is much easier to tell if a human being is looking at me because I can see the direction of her gaze.  Evolutionary explanations can rarely be tested in the same way that water can be tested for bacteria.  Mostly we have to make do with reverse engineering.  Why the large whites of the eyes?  It might be an accident of eye evolution.  Even if it is, that doesn’t mean that it wasn’t adaptive for another purpose once it was in place.  It might be adaptive for another reason, but the same holds.  All we can say for sure is that it doesn’t look like a complete accident that a species that benefits from interpersonal cooperation has eyes that allow one individual to tell when another is paying attention to her. 

Finally, there is this comment:

If the Greek translation of Aristotle’s ultimate theory carries any weight one might leap to conclusions about the composition of genes. In this era of biotechnology that is a big deal. The courts have wrestled with the question AMP v. Myriad 2013 and have settled upon a kind of genes are like chemistry analogy. It serves Occam’s Razor to simplify its work in resolving disputes between corporate and others interests. According to this analogy the simplest explanation is that genetic information is linear and their coded information is deterministic. Research scientists whose motives exclude the allure of profit and fame as primary incentives, increasingly theorize that a better analogy for the behavior of genes is more quantum physics. Their actions are less predictable than the simplified linear understanding that applies to chemistry. If I am correct, this fits Ron’s remarks about contextual influences.

I have been aware of this for a long time.  Since the discovery of genes, it has been tempting to believe that genes are legible: each codes for one trait and the code can be deciphered.  Once we decipher it, we can edit the code to produce the traits we desire.  I don’t think that anyone in the relevant fields believes that there is a simple, deterministic relation between genes and traits.  A single gene may code for many traits in the body, from the brain to the brawn.  Moreover, many genes depend on environmental inputs for their operation. 

Our genes code for flexibility.  When a cat decides whether to chase a rabbit or a fisherman whether to cast his line, each is making choices.  As I have argued in these posts, evolution works through animals by allowing each to pursue its own agenda.  A bull elk in a rut is not trying to produce the next generation of elk.  He is trying to beat the snot out of other bulls.  When I make dinner for my wife, I am not trying to get my genes into the next generation.  I am trying to make her happy.  That is how the beautiful emerges from the merely necessary.  

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.  

Getting Over the Either Or

Several years ago in my Human Nature & Human Values course, a student indignantly objected to the whole idea I was presenting.  He told that he and several of his friends once jumped into a lake to save a poor fellow from drowning.  We didn’t do it, he insisted, because we were trying to survive or make babies!  We didn’t even think about what we were doing.  We did it because we cared about the poor bastard in the water. 

This turned out to be one of those great teachable moments.  I drew a chart on the board that started like this:

phenomenon	Dropping a hot object
Proximate cause	Pain
Function	Avoiding physical injury
Secondary Evolutionary Explanation	Personal Survival
Primary Evolutionary Explanation	Personal Reproductive Fitness

Dropping a hot object is something we do without thinking about it.  It is a reflexive reaction to pain.  Now suppose that someone said that physical injury had nothing to do with it.  I didn’t drop it because it might have injured me; I dropped it because it hurt.  That would surely be a mistake, not because the latter part is wrong but because both explanations are correct.  Yes, pain is a motive.  However, it is also obviously functional.  It encourages us to avoid things that might result in physical injury. 

One might then wonder how we came to be such creatures as are hurt by things that injure us.  The secondary evolutionary explanation explains how the functional device is maintained by its direct functional advantage, and the primary evolutionary explanation is the ultimate explanation of the action.  The same thing is true of my student’s wonderful story. 

phenomenon	Dropping a hot object	Saving a stranger from drowning
Proximate cause	Pain	Concern for another’s welfare
Function	Avoiding physical injury	Reciprocity
Secondary Evolutionary Explanation	Personal Survival	Forming cooperative networks for the sake of mutual survival
Ultimate Evolutionary Explanation	Reproductive Fitness	Reproductive Fitness

The concern for a stranger’s welfare was the genuine reason that my friend jumped into the water.  Like pain, this concern is obviously functional.  All of us are better off if each of us is prepared to jump to another’s aid.  It’s a case of both, not either or.  My secondary evolutional explanation here points to something like group selection, but I will ignore that for the moment.  Suffice it to say that the evolutionary explanations do not in any way contradict the common sense explanations that my student preferred. 

Yesterday, as I was laying out Lee Dugatkin’s four routes to cooperation, another student suggested that human beings, unlike animals, think about what they are doing.  Surely we cooperate because we can see that it makes sense, and not (or not solely) because of evolved instincts.  I emphatically agreed that deliberation is an important factor in human cooperation; however, I insisted, our deliberation is guided by social emotions.  We would reach different conclusions as a result of deliberation if we had a different set of emotions.  Here is another chart:

phenomenon	Ostracizing a cheater from the group
Proximate cause	Righteous Indignation
Function	Encouraging honest cooperation within the group
Secondary Evolutionary Explanation	Maintaining cooperative networks for the sake of mutual survival
Primary Evolutionary Explanation	Reproductive Fitness

When confronted with a cheater, a group of homo sapiens may think long and hard about what do.  If they decide to kick the dead weight out of the group that may be because they have calculated that he isn’t worth his weight.  Or they may simply be so mad that they don’t care about shrinking the group.  Either way, their indignation is a powerful motive and the human capacity for that emotion is clearly functional. 

The hardest part of teaching evolutionary social theory to undergraduates is getting them to see that common sense interpretations of social phenomena are not opposed to, let alone exclusive of, functional and evolutionary explanations.