Modern Biology As A Series of Footnotes to Plato & Aristotle

While Addy Pross failed to convince me that biology is chemistry, he has confirmed my long held opinion that modern biological science has largely come back around to Plato and Aristotle.  I provided one example in my last post.  Here is another. 

Pross’ book centers on what one may call the central problematic of modern biology: the fact that, while biological processes are and must be perfectly consistent with the natural laws that govern all physical substance, organisms seem to have sets of rules that are entirely their own and they seem to go in the opposite direction from all inorganic chemistry.  Organisms move uphill toward greater degrees of complexity rather than move downhill toward simplicity. 

As I have detailed in previous posts, Pross deals with this by distinguishing between static complexity (which governs everything below the level of molecular replicators) and dynamic kinetic stability, which is displayed by replicators.  Whether this in any way moves toward a solution rather than merely restating the problem, I will ignore here. 

It does seem to me that this question maps back onto the history of ancient Greek philosophy quite well.  For the ancients, the central problematic was how to explain coming to be and change.  Let us state it in its simple form:

If something new can come to be, it must come to be either out of what is or out of what is not.  It cannot come to be out of what is, because what already exists cannot come to be.  It cannot come to be out of what is not, because there is nothing there to come to be out of. 

That this is not mere word play is evident by the emergence of two schools of pre-Socratic thought.  One was that of the monists.  They argued that, in fact, nothing ever does come to be or change at all.  That is because there is really only one thing and it never changes.  Consider, by way of analogy, a pyramid.  It is wide at the base but narrow at the top.  This does not mean that it changes, but only that it offers different aspects to different points of view.  Likewise, the small tree in my yard seems to become bigger as time goes on.  This is an illusion.  It is always one thing at one time, and time is just another dimension along which different aspects are offered to the observer. 

If this seems implausible, it is well to consider that it is the view of most modern physicists.  Time is just another dimension, analogous to the three dimensions of space.  At time T1 I am at position X1, Y1, and Z1.  This fact is always true and does not change.  At T2, I have moved to X2, etc.  Reality viewed as a whole is nothing more or less than the sum total of all such facts.  None of the facts ever changes. 

A less radical solution was offered by the ancient atomists.  They posited that the only real things are the uncut particles out of which everything else is composed.  The atoms (uncut things) are eternal.  They never come to be nor do they ever decompose, since they aren’t composed of anything except themselves.  All those things that appear to come to be, like stars and people, are mere aggregates of atoms.  Complex things do not exist in any real way and so it is unnecessary to account for their coming to be. 

Aristotle cut the Gordian knot first by positing three principles: potentiality, actuality, and a substratum.  How does an iron skillet come to be?  It comes to be from a lump of iron which is potentially a skillet.  The iron is heated, becoming red and hot from what was black and cold.  It is then shaped into an actual skillet.  Thus it comes to be from what is not: the iron that was potentially but not yet actually a skillet.  It also remains what it is, still iron after the shaping. 

Contrary to the atomists, something new has come to be beyond the mere aggregation of the materials.  The skillet has powers that the lump of iron did not have (for example, holding a few lamb chops in hot oil).  Contrary to the monists, there is no necessity to dispense with the element of time.  As the iron was potentially a skillet, it was also potentially something else (a hammer?) or might just have continued its career as a lump.  Potentially suggests an open future. 

This account of coming to be and change is hylomorphic, from the Greek words for matter and form.  It recognizes form as something real, but requires a material substratum underlying the processes of generation and change.  Let us map this back onto Pross’ categories.  In simple chemical reactions, the nature of the materials controls all the action.  Forms and formal processes are entirely derivative from the elements and the downhill pressure of the second law of thermodynamics.  Hylomorphic explanations recognize that the same material can have very different powers in different arrangements.  This is true even of the inorganic world.  A cloud behaves differently from a pool of water. 

Aristotle made a leap beyond simple hylomorphism when he recognized individual organisms as substances.  A substance (ousia in Greek) functions as a bearer of properties and as the substratum of change.  This horse over here is so large and of a certain color.  It persists as what it is while it grows from a foal to a yearling to a filly to a mare.  This kind of persistence is what Pross means by dynamic kinetic stability.  The horse continual communicates its being over time, for as long as it lives.  This kind of substance apparently emerges on earth with the first genuine replicators, presumably the ancestors of RNA molecules. 

At some point in his thinking, Aristotle began to recognize the species as a substance.  If what persists over greater periods of time is more real than what persists over shorter terms, then the species is more substantial than the individual organism.  By taking this step, Aristotle was getting at something that has stirred the pot of the modern philosophy of biology.  What is the unit of selection in evolution?  The most obvious answer is the individual organism.  A less obvious but very robust answer is that it is the genes.  The individual may be viewed as a vehicle for the genes, discarded as they mechanically pursue immortality.  At least two philosophers of biology (Michael Ghiselin and David Hull) have argued that conspecific populations are genuine individuals.  They are following the track laid down by the philosopher. 

That, as rich and rewarding as it is, is the limit of Aristotle’s approach.  Aristotelian substances, however large, exist as visible objects at some present moment.  Modern Darwinian biology can conceive of a species as an object that extends backwards into the past.  When Darwin spoke of the origin of the species, he might have meant a single species consisting of all the organisms on earth.  Such an object, if we choose to recognize it, is Platonic rather than Aristotelian.  All existing organisms and populations of organisms are buds and branches of one great, invisible tree. 

Or we might consider that what really persists over geological time is not the vast number of replicators but replication.  Genes, after all, are more ephemeral than the organisms they underwrite.  They must be constantly recreated.  Replication is an idea, but not merely a nominal idea.  It logically enables and constrains the processes of ontogeny and evolution. 

Praying Apes & Steven Pinker

Sitting at a table in a Chinese restaurant in San Francisco, I was asked how it is possible for an ape to pray?  This was a direct challenge to my interest in evolutionary explanations for human political and moral behavior. 

I responded that a wide range of animals have two sets of limbs, fore and aft, and that in one species of ape the pads of the forelimbs can be brought together in front of the chest.  I was being facetious, of course; but not altogether facetious.  Prayer often involves physical activity and such activities are both enabled and constrained by biological facts. 

I went on to suggest that the same is true of the spiritual activities involved in prayer.  Like most animals, human beings have an evolved capacity to infer what is invisible from what is visible.  When a polar bear is hunting, it does not look for anything that looks like a seal.  It looks for mist coming from a hole in the ice.  A human hunter tracking prey looks first not for the animal itself but for signs of its passing and course. 

Unlike all other animals, the human ape has a robust capacity for forming a theory of mind.  This means that I understand that other people and other animals have minds like I do and I can use this fact to predict their behavior and engage with them.  This capacity underwrites both our social lives and our animal husbandry. 

Inclined by our evolved capacities to look for signs of what is invisible and to infer intentions and will behind visible behavior, it is not difficult to understand how this ape learned to pray.  Of course, these instincts can lead to mistakes.  The erupting volcano is not really angry nor do the entrails of the bird really indicate the will of the gods.  Or so I suppose. 

However, that does not mean that prayer is always or even mostly a mistake.  All prayer is a turning of the human mind toward the divine.  In that sense it is like treasure hunting, which can be understood regardless of whether there is treasure underneath the X.  Understanding how our evolved inclinations make prayer possible and how they influence its expressions cannot tell us whether the object of that turning exists or what its character is.  Such an understanding certainly does not allow us to infer that the treasure does not exist. 

Steven Pinker has a piece in The New Republic attacking the critics of “scientism”.  This is a pejorative term meaning in general the idea that science can explain everything and (always) in particular, the idea that science can explain something the critic does not want science to explain.  The term is typically deployed against those who inquire into the evolutionary and developmental roots of human culture. 

Pinker thinks that science and the humanities are not at odds with one another.  He makes a strong case and one with which I am largely in agreement.  To add my own two cents, evolutionary science can tell you a lot about why Romeo and Juliet were attracted to one another.  It can tell you a lot about why we love such stories.  Human beings are sexually reproducing creatures.  Our mating behavior is extraordinarily rich in the psychological depth of our displays and motives.  Each of us is interested, obviously, in our own loves and lusts and (almost as obviously) in those involved in third party arrangements.  Our interest in Romeo and Juliet is intelligible. 

Pinker draws a useful distinct between intelligibility and reductionism. 

Demonizers of scientism often confuse intelligibility with a sin called reductionism. But to explain a complex happening in terms of deeper principles is not to discard its richness. No sane thinker would try to explain World War I in the language of physics, chemistry, and biology as opposed to the more perspicuous language of the perceptions and goals of leaders in 1914 Europe. At the same time, a curious person can legitimately ask why human minds are apt to have such perceptions and goals, including the tribalism, overconfidence, and sense of honor that fell into a deadly combination at that historical moment.

Yes.  The laws of physics, chemistry, and biology were in full force when a bullet pierced the shirt of the Archduke Ferdinand.  If biology has something to offer here, it is because biology has principles that are not derivable from chemistry and physics.  Likewise, historical analysis must determine factors (chance and culture) that are not derivable from biology. 

While Pinker thinks that science and the humanities are not at odds with one another, he clearly does think that science rules out certain ways of thinking about the human things. 

The moral worldview of any scientifically literate person—one who is not blinkered by fundamentalism—requires a radical break from religious conceptions of meaning and value.

To begin with, the findings of science entail that the belief systems of all the world’s traditional religions and cultures—their theories of the origins of life, humans, and societies—are factually mistaken. We know, but our ancestors did not, that humans belong to a single species of African primate that developed agriculture, government, and writing late in its history. We know that our species is a tiny twig of a genealogical tree that embraces all living things and that emerged from prebiotic chemicals almost four billion years ago. We know that we live on a planet that revolves around one of a hundred billion stars in our galaxy, which is one of a hundred billion galaxies in a 13.8-billion-year-old universe, possibly one of a vast number of universes. We know that our intuitions about space, time, matter, and causation are incommensurable with the nature of reality on scales that are very large and very small. We know that the laws governing the physical world (including accidents, disease, and other misfortunes) have no goals that pertain to human well-being. There is no such thing as fate, providence, karma, spells, curses, augury, divine retribution, or answered prayers—though the discrepancy between the laws of probability and the workings of cognition may explain why people believe there are. And we know that we did not always know these things, that the beloved convictions of every time and culture may be decisively falsified, doubtless including some we hold today.

I happen to believe most of what Pinker states in that passage, but I am pretty sure that I do not know any of it and neither does he.  I am very dubious about “spells, curses, [and] augury” but I cannot think of what science I can rely on to rule out “fate, providence, karma, divine retribution, or answered prayers”.  In fact, I know that such things cannot be ruled out because that would depend on assumptions that science requires but cannot establish.  Science assumes uniformity in physical laws both across space and time, for which reason it rules out miracles.  Such an assumption is very useful and indeed very powerful; however, it is still just an assumption.  It cannot be verified by scientific reasoning since the latter requires it.  If there were, indeed, an omnipotent God, outside of time and space (an alternative assumption) then quite literally everything goes. 

Still, it was right for Pinker to issue this challenge.  It is quite true that science is not the enemy of the humanities.  I would go further to say that it is not the enemy of religion either.  This does not mean that is rests comfortably with either.  Science should make us uncomfortable. 

Leo Strauss argued that one of the great sources of vitality in Western Civilization is the conflict between reason and revelation.  From the time of Thomas Aquinas, to be sure, intelligent persons have had to wrestle with two claims to wisdom.  While I think that Pinker is right to push the claims of science as authoritative, I am also grateful for the honorable opposition.  All science is just a special case of philosophy.  Philosophy is rooted in the knowledge of what one does not know.  Without religion, who would continue to remind those of a scientific mind that they do not know what they think they know?

Pross Proves Plato

It is a commonplace in the academy that we learn as much or more from intelligent errors than from the modestly correct.  Addy Pross’ book What is Life? has utterly failed to convince me that the title of his penultimate chapter is correct; i.e., that biology is chemistry.  What he has convinced me of is that Plato was closer to the truth than Aristotle. 

The basic problem that Pross addresses is how to reconcile our understanding of non-living, non-replicating nature (governed by the second law of thermodynamics) with our understanding of organisms and their prebiotic (but replicating) chemical ancestors.  Pross finds the solution in a distinction between two kinds of stability: static stability and dynamic stability.  Water molecules are statically stable: they remain stubbornly what they are over long periods without change.  Bacteria are dynamically stable.  They remain what they are by a process of constant change that keeps bringing the form back into existence. 

Just as the second law of thermodynamics is the driving force that governs all chemical reactions, so all dynamically stable systems like organisms and replicating molecules are governed by a similar law:

Replicating chemical systems will tend to be transformed from (dynamically) kinetically less stable to (dynamically) kinetically more stable.

Once diverse populations of replicators get going in the history of life, more dynamically stable replicators out compete less dynamically stable competitors.  This law governs the evolution of all life up to the present and, presumably, for the duration. 

Here’s where Aristotle and Plato come in.  While they had no viable chemistry, they were very good at thinking about biological form.  Aristotle famously rejected his teacher’s theory of forms as independent entities in favor of the view that form is an abstraction from existing organisms.  How do we understand a horse?  This horse, here, is the real thing.  It consists of a certain collection of materials that realize a certain form.  The form of the horse is an abstraction from really existing horses, but it allows us to sort horses out from other organisms.  Thus it is a species form. 

Aristotle was later drawn to the view that the real thing is not the individual horse but the species, since the one comes and goes but the latter persists.  What persists over time is more robustly real than what does not.  Still, the form is an abstraction from something really embodied now (and always) whether the embodied thing is a horse or all the horses.  The laws that govern the existence and development of each species are specific; there is nothing more general than the species that controls their natures. 

Plato looked at the problem the other way round.  Form was primary; individual organisms (and presumably populations of organisms) are derivative.  Plato’s view was rooted in an analysis of human intelligence.  When we view a tree from a great distance, it looks very small.  As we approach it, it seems to grow larger.  Near the tree, it is very large indeed.  Yet the tree has not changed; what has changed is our perspective.  There is one thing, the individual tree, behind the shifting perspectives and that one thing is more real than the appearances. 

Plato’s great innovation was to extend this analogically to understand what a species is.  When we move from one tree to another, we recognize both of them as in some sense the same thing‑different examples of tree, just as we recognized the various views of a single tree as the same objective thing.  Perhaps this is because there is one thing behind all the individual trees that our minds are getting a dim grasp of.  That is the idea of a tree and it is more real than individual trees because it is not susceptible to change or decay.  It defines what a tree is for all actual trees and for all trees that may or may not come to be in the future. 

This account has been subject to a lot of derision over the millennia, but Plato’s Socrates was always careful to advance it as provisional.  It is not necessarily this, he would say, but something more or less like this.  It is unclear whether he really believed in the idea of a complex object like a tree, or whether the true ideas were more like mathematical principles. 

It strikes me that Pross’ law of dynamic kinetic stability looks a lot like a Platonic form.  It is not a mere abstraction from actual organisms or populations.  It is a logical rule that (if valid) governed all the emergence of all replicators from the Ur-replicating molecules to the replicating elephants.  It will govern all organisms that emerge in the future. 

Aristotle laid down a very good foundation for biology.  I have argued that modern biology is now coming round to his view on a lot of things.  It may be, however, that Plato’s view was correct at a deeper level. 

What is philosophy?

I am teaching four sections of philosophy this fall but in an unusual arrangement.  Two of them are traditional general education course; one is an honors seminar; and one is online.  As always, I begin by asking myself what the Hell I am talking about.  Philosophy is distinct from the other courses I and other professors teach in so far as most students have no idea what it is they will be doing in such a course.  A math student begins with some idea of numbers and their manipulation; a student of literature begins with some idea of reading; but what does a philosophy student begin with?  Here are some of my introductory reflections. 

Philosophy is a human activity.  To philosophize is to do something that philosophers do.  It is a fundamental activity in the sense that to do it involves taking a basic position with regard to oneself and the world around oneself.  In that sense it is like religion, politics, war, and business.  Such activities shape both individuals and communities.  As some Chinese wit said, to the man who makes shoes, the whole world is made of leather. 

It may be argued that, of all such fundamental activities, philosophy has had the greatest impact on human history.  Philosophy gave rise to science and science to modern science and the latter to modern technology.  These underlie the astonishing changes in the world over the past two centuries.  One of the reasons that this impact is so profound is that, again unlike other similar activities, philosophy does not seem to arise spontaneously in different places. 

Politics, religion, war, and trade are ubiquitous among human societies.  They arise spontaneously wherever enough human beings gather.  Philosophy seems to have arisen spontaneously only once, on the western shore of Asia Minor around the turn of the sixth century BC.  Since that time, everyone we know about who has philosophized has done so after encountering the philosophical tradition either by meeting a philosopher or reading what some philosopher wrote. 

In saying this, one might suppose that I am privileging “Western philosophy” over other philosophical traditions such as Eastern philosophy.  I do not at all imply that alternative traditions of thought are inferior; however, I do hold that they are distinct from what Thales or Socrates or Leo Strauss meant by philosophy.  It is perhaps easiest to begin by saying what philosophy is not. 

Philosophy is not the elaboration of doctrine.  Most of what is called Eastern philosophy falls into this category, as for example the Abhidharma tradition in Buddhism.  These traditions begin with certain fundamental principles backed by religious authority (e.g., all compounded things are impermanent).  They proceed by elaborating and reconciling.  They value of such enterprises depends, of course, on the value of the original principles.  Whatever one thinks of this (and I have a deep respect for Buddhist traditions), it isn’t what Socrates was up to. 

Philosophy is not religion.  Religions begin and perhaps end with an authoritative statement.  Hear, Israel, the Lord your God is one!  Philosophy begins with questions and perhaps remains with the same.  Likewise philosophy is not mysticism, which views rational thought as an obstacle to wisdom. 

Philosophy is emphatically not a statement of personal beliefs that one holds without bothering much to think about them, as in: “my philosophy is live and let live.” 

So what is it?  I will offer the following as the simplest possible answer:

Philosophy is the attempt to become wise by relentless questioning. 

That definition fixes the essence of philosophy in its goal (wisdom) and its method (questioning).  Both must be present if what is being done is genuinely philosophical.  The definition is sufficient if you read back the method to understand the goal, which is to say that questioning as a path to wisdom presupposes a certain view of wisdom. 

You might suppose that wisdom is a largely meaningless term, since it is necessarily understood in different ways by the distinct activities identified above.  You would be wrong.  Wisdom means simply having the answers to all the important questions.  Again you might object that there are a very large number of important questions and that different cultures and distinct professions within a culture will select out their own privileged set.  Again, you would be wrong. 

There are really only two important questions.  The wise in any group, from the elders in the tribe up to the priests and divine emperor, rest their claim to wisdom on the answers.  The two questions are:

What is the nature of the world?

How should we live in it? 

The tribal elder will present as a wise person because he or she knows the authoritative stories (the world is mud on the back of a giant turtle and curiosity killed the cat) and because his or her long life provides a multitude of illustrations.  The prophet is wise because he knows that God created the heavens and the earth and that fear of God is the guide to the best possible life. 

Philosophy begins when someone first took seriously the distinction between opinion and knowledge, between the way that things seem to be and the way that they really are.  Water, ice, and vapor seem to be different things, as different as caterpillars and butterflies.  But wait!  Don’t ice and vapor seem to come from water?  Could it be that all three are different forms of the same thing?  Okay, so the world is mud on the back of a really big turtle.  What is the turtle swimming in?  Philosophy begins by questioning both appearances and the stories that we tell about them. 

Perhaps the best illustration of philosophy occurs at the beginning of Plato’s magnificent Republic.  Socrates asks the aged Cephalus

What do you consider to be the greatest blessing which you have reaped from your wealth?

Cephalus replies that he is preparing for death by making sure that all his debts are paid, so he will carry no moral deficit if and when he faces the afterlife.  So is justice paying what is owed?  Socrates isn’t so sure. 

Well said, Cephalus, I replied; but as concerning justice, what is it? --to speak the truth and to pay your debts --no more than this? And even to this are there not exceptions? Suppose that a friend when in his right mind has deposited arms with me and he asks for them when he is not in his right mind, ought I to give them back to him? No one would say that I ought or that I should be right in doing so, any more than they would say that I ought always to speak the truth to one who is in his condition.

That is philosophy.  One question is followed by another until all questions have been answered.  Of course, questions always remain or, at least, questions still remain.  As long as that is so, the wisdom sought by the philosophers is beyond their grasp. 

The philosopher is the person who refuses to stop asking questions until all questions have been answered.  Philosophers are rare, but anyone can participate in philosophy in so far as he or she remains alive to the unanswered questions and can hear their seductive whispers.