Thursday, March 7, 2013

Evolution of Virtue 3

 Here is the third section of my paper on the evolution of virtue.  

Aristotle’s account of virtue is rooted in his understanding of biology.  He advanced a model of the human soul that was tripartite and hierarchical.  According to this model, human beings share with all organisms a basic level of soul that he called vegetative.  This level of soul includes such basic powers as feeding, growing, and producing waste.  It opens up an existential dimension of value that extends from flourishing to decay and death. 
While all animals share in the organic powers that make up vegetative soul, animals have powers that plants do not have: motility and perception at a distance.  These powers open up a second existential dimension: pain and pleasure.  Unlike plants, animals can have good and bad moments and good and bad days. 
Human beings obviously share in all of this.  Just as obviously, we alone possess a third basic power: logos.  Human beings are capable of speech and reason.  Logos makes it possible for us to distinguish between what something looks like and how it really is.  Most significant for moral thought, this means we can distinguish between what looks good and bad and what is really good and bad for us. 
Aristotle’s biology is unfortunately famous mostly for his howlers.  He believed in spontaneous generation, for example.  Yet he got most of it astonishingly right, according to modern evolutionary biology.  His tripartite soul maps very well onto evolutionary history.  Evolution does not work by adding new organisms to old ones built according to new blueprints.  Instead, it preserves what works while piling new systems on top of the older ones.  Some genes are unique to humans.  Others, like the famous tool box genes, are shared by all animals.  One the three basic systems that comprise the human brain is old enough to be called reptilian.  The neo-cortex, on the other hand, seems primary only in the primates. 
Aristotle models the human soul in much the same way as his teacher Plato (or Plato’s Socrates) did: by means of a political metaphor.  One part of the human soul is distinctly non-rational in so far as it does not respond to persuasion.  This includes all the organic activities that are rooted in the body and that are shared with other organisms.  It includes the sensations, among which are the pains and pleasures.  Logos, by contrast is uniquely human and its power is that of conscious thinking.  In between is what we might call the middle part of the soul.  This part of the soul includes the various passions.  Each passion includes an element of judgment: if I am angry, I am angry at someone about something.  Unlike the sensations (let alone the unconscious organic processes) the passions are rational in so far as they are susceptible to persuasion.  In the well-ordered human soul, reason rules the passions politically; i.e. reason both commands and persuades them.  Reason and passion together rule the sensations royally or even despotically, by command alone. 
From the viewpoint of evolutionary theory, the political metaphor is no mere convenience.  The passions develop their rational dimension precisely because they develop in the course of our evolution as political animals.  To the degree that human beings are capable of self-government, individually and collectively, it is because the psychological capacities underlying self-government were selected for.  The selection pressures that shaped these capacities were created by the advantages that highly cooperative human associations enjoyed.  Creatures capable of a sense of “we-ness” as Michael Tomasello has put it, who have a sense of moral obligation that they cannot easily escape, have largely inherited the earth.  Precisely because human souls were not fashioned anew but rather were built up out of preexisting psychological powers, it is both possible and necessary for the more rational elements to govern the less rational ones.  The moral dimension is one of the trajectories of our evolutionary history. 
When Aristotle looks for the nature of the virtues, he notes that there are three things in this human soul.  He is focusing here on consciousness or mind as modern philosophy calls it.  The three things are “feelings”, powers, and dispositions.  Under the first category, he explicitly lists a number of passions, including desire, anger, fear, and courage.  The powers indicate the capacity of the soul to generate the various feelings.  We can certainly suppose that there are creatures incapable of any of the feelings or only some and we can imagine that we might have existed with a different emotional palette.  By dispositions (or habits), he indicates that fact that each person may be disposed to experience each of the passions in an appropriate or inappropriate way.  Someone may be unable to feel sufficient anger when he has been genuinely offended or feel more anger than is reasonable in any situation. 
All three of these categories fit well within the context of an evolutionary analysis.  The emotions that we feel depend on an innate capacity to generate precisely this set of passionate motives.  Each emotive power exists in us because it was selected for.  In some set of circumstances that reoccurred frequently over time the power to produce an emotion contributed to the reproductive success of our ancestors.  To take a single example, a capacity for righteous indignation promoted cooperation by encouraging members of human communities to punish or ostracize those who violate fundamental social obligations.  When we see such violations, they look disgusting.  There is good evidence that the part of the brain that registers emotional disgust is the same part of the brain that registers physical disgust, as for example what we experience when we small rotting meat.  That is a good example of how evolution retools an existing emotive power for a fundamentally new function. 
To some degree, our emotional dispositions are innate.  Some persons are innately more prone to anger or compassion that others and men are in general more prone to violent aggression than are women.  On the other hand, in all or almost all human beings, the dispositions are flexible and subject to learning or conditioning.  Such flexibility makes every kind of sense in an evolutionary context.  It allows human communities to adapt to a wide range of environmental niches without having to suffer the losses that direct selection entails.  Whereas a species of bacteria might respond to a change in circumstances only after a catastrophic loss of numbers, a human society might respond simply by changing the characteristic behavior of its members.  It also allows the community to cultivate certain passions in certain ways, thus producing what we would call moral culture.  Finally, it allows an individual to cultivate himself. 


  1. "So genes are unique to humans." Should probably be "Some genes . . ." And that's not entirely right, either. Even genes like the FOXP2 gene is shared by, say, chimpanzees -- the difference is the two mutations we have that chimpanzees do not. One would do better to look at the anatomical effects of the gene mutations. The giant fusiform cells that are found only in the great apes, or the fact that human's seem to be neotenous, which has an effect on gene expression timing.

    1. Troy: thanks for the comment. You correct that the word should have been "some". I will give the rest of your comment some thought. I really like the example of the toolbox genes!

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  3. Neurons are virtually indistinguishable among higher mammals: NPR.

  4. Larry: interesting. I think it reinforces Aristotle's point. At a basic level, all organisms are the same.

  5. "There is good evidence that the part of the brain that registers emotional disgust is the same part of the brain that registers physical disgust."

    This is fascinating. Is it only true of disgust or are similar parts of the brain activated when we see a steak and when we see, say, Mother Theresa?

  6. Miranda: If there is evidence of common brain area for appetizing things and admirable people, I do not know of it. As noted in a recent post, however, it seems likely that pro-social emotions are built atop the neural architecture of the parent-child bond. Those are very old and I suspect that they probably have little to do with appetite.

    1. That came out sounding a lot more Armin Miewesish than I had intended it to. I phrased it the way I did, because your statement led me to look up the spoiled meat, moral digust comparison link. I ended up reading an article that used reactions to Anthony Weiner and John Edwards as examples (

      I used steak as an example, because it seemed like the opposite of spoiled meat and Mother Theresa because she seemed like the opposite of Anthony Weiner. In retrospect, that was probably a bad idea.

      My question is not so much, "Do we think of moral people in the same way we think of tasty food?" It is, "Do our brains react to things we find morally appealing in the same way we react to things that are physically appealing?" Like steak. Or New York Bagels. Or is disgust unique? I will go back and re-read the parent-child bond post!