Biology is Not a Materialistic Science

In the two essays by Evelyn Fox Keller and John Dupré that I commented on in my last post, both authors describe themselves as materialists.  Keller says that she is an “unambivalent materialist” and Dupré says

Like Keller, I am a materialist.  That is to say, I do not believe that there is any kind of stuff in the world other than the stuff described by physics and chemistry.  There are no immaterial minds, vital forces, or extra-temporal deities.

It is hard not to read these statements as other than prophylactic confessions. They are nervous that any distance from a reductionist position might be taken for a belief in magic. 

I would argue that neither of them are in fact materialists because any materialism worthy of that name is untenable.  I suggest that the promiscuous use of the term arouses unnecessary opposition to science and especially to Darwinian biology and worse, it is misleading.  Materialism means nothing if it does not mean an account of something that reduces that thing to the properties of its material constituents.  So what does it mean when two philosophers of biology feel obliged to profess materialism and then deny that such reductionism is possible? 

To understand what materialism might mean it is best to begin with a simple materialist explanation.  Consider an iron bar.  It has color, weight, solidity, and other properties such as magnetism and electrical conductivity.  The bar is made out of small bits of iron, which we may then see as its material.  The properties of the whole result from the addition of the properties of the uniform parts and thus the one is explained by and therefore reducible to the other. 

Now suppose that we heat the bar.  What explains the new properties of the object‑its capacity to warm, turn red, and liquefy?  One explanation is that by heating it we have added new material to the existing material‑particles of heat to particles of iron.  The new material we may call caloric or phlogiston.  As water softens soil and makes it flow, so caloric softens iron and, additionally, makes it red hot.  It’s not an implausible suggestion at first glance.  It explains why the hot iron will warm a surface that it rests on.  The caloric is leaking out into the surface, just as water leaks from a sponge into a table cloth.  The caloric theory of heat is what a genuinely materialist explanation looks like. 

By contrast, the molecular theory of heat denies that heat is something material.  It is instead the energy with which the molecules of a substance collide against each other.  Heating the iron bar does not, as such, introduce a new material into the object.  Instead, it changes the state of the same material.  That is a non-materialist explanation precisely because it does not require belief in “any other kind of stuff” than the stuff of iron. 

Genuinely materialist explanations must work like the caloric theory of heat.  Any property of something would have to be explained by reference to the properties of its material constituents alone and any change in properties would have to be explained by the addition or subtraction of material constituents.  A genuine materialism would have to restrict itself to materialist explanations.  It is not as if such a materialism has not be attempted.  Anaxagoras may have been one of the few genuine materialists in the history of philosophy.  Aristotle made short work of him. 

I return to Dupré.  When he says that “there are no immaterial minds, vital forces, or extra-temporal deities”, in addition to confessing atheism he is in fact rejecting materialist explanations for biological phenomena.  The reference to “vital forces” indicates the idea that there is some kind of stuff in living things that animates them.  That explanation of life was, at least originally, a thoroughly materialist doctrine.  According to the ancient atomists (Lucretius being a good example) the soul was a kind of substance present in living bodies.  When a living body was cut open (say, by a sword) the soul particles leaked out, causing death.  That is what a materialist biology would look like!

Much the same is true of “immaterial minds”.  The reference here, I presume, is to substance dualism.  While dualists attempted to explain consciousness by the supposition of an “immaterial substance”, they are, almost always, positing a division in the kinds of material.  Physical substance forms physical things while mental substance forms ideas, impressions, etc.  This is why conman spiritualists in the 19^th century had themselves photographed covered with cotton candy like “ectoplasm”. 

What is wrong with vitalism in biology and dualism in philosophy of mind is the same thing that wrong with the caloric theory of heat: they posit material substances that do not exist and propose materialistic explanations for phenomena which cannot be explained in material terms. 

To see that modern biology cannot be a materialistic science, one only has to compare it with Aristotle’s biology.  Aristotle believed in spontaneous generation.  Under certain conditions of heat, moisture, etc., material constituents spontaneously generate simple living organisms.  This happens, as Aristotle thought, frequently in swamps and perhaps dead bodies.  If that were true, then biology would be a much reductionist science that it is.  Aristotle was one of the most vociferous opponents of reductionism and, while he certainly incorporated materialist explanations in his biology, he was no materialist.  Yet he was more materialist than modern biologists.  The latter hold that all living organisms are the offspring of pre-existing organisms. 

Spontaneous generation must have happened at the very beginning of life on earth, but what was added to existing materials was not some new material but form‑a certain primitive structure and the process of self-generation and autonomous action.  Like the molecular theory of heat, any viable understanding of living organisms is non-materialistic.  Magical explanations are to be rejected precisely because they invent mythical materials and rely on inappropriately materialistic devices. 

As Aristotle recognized, materialist explanations are often appropriate in science.  Red paint is red because somebody added red powder to water.  Snowflakes take their amazing shapes because water molecules crystalize in certain patterns.  A baby comes to be because it comes to be out of something.  A materialistic biology is impossible because babies come to be something and come to be towards something and come to be because a process of ontogeny is pushing it out of its original state, to survey Aristotle’s four causes.  It is high time that philosophers and scientists stop calling themselves materialists when they are nothing of the sort. 

Contra Reductionism in Biology

I just finished reading two excellent essays in Contemporary Debates in Philosophy of Biology.  The book, edited by Francisco J. Ayala and Robert Arp, consists of a series of duets: essays taking opposite positions on basic questions in that domain.  The first essay was by Evelyn Fox Keller, who I had the pleasure of meeting in the mid-nineties during a six week seminar at Dartmouth College, led by Roger Masters and Ron Perlman. 

Keller’s essay is entitled “It is Possible to Reduce Biological Explanations to Explanations in Chemistry and/or Physics”.  It is a very good introduction to the basic problem of reductionism in biology.  It is followed by an essay by John Dupré.  Dupré adds the word “not” to Keller’s title. 

It tells almost all that Keller begins by largely conceding the point.  She notes that in physics and chemistry, the fundamental principles are common denominators and they are coextensive, or equated, with the simple.  To provide my own example, the periodic table of the elements, so basic to chemistry, is literally a poster for simplicity.  By contrast, “whatever the meaning of fundamental in biology, it clearly cannot be equated with simple, nor is it at all obvious that it is common to all biological entities”.  Physical principles are simple and apply to everything in their domain.  Biological principles are rather few if any, and they are very complex.  The best of them admit to exceptions.  So how can we hope to reduce the one to the other? 

Keller goes on to do an admirable job of lubricating the track between the hard sciences of chemistry and physics and the flaccid science of biology by introducing a non-biological, simplified version of function.  In this view, if I understand it, a river functions as part of a system whereby water leaves the ocean for the sky, the sky for the mountains, and the mountains to get back to the sea.  The river is functional because “it contributes to the self-regulation of some entity of which it is a part.”  I note that she was quoting William Wimsatt here, who I also met in Dartmouth.  Pardon my name dropping, but this is taking me down memory lane. 

That simple version of function is fully compatible with physics.  However, while the river functions to get water down it doesn’t function to maintain some internal state of equilibrium (or more accurately, specified disequilibrium).  It doesn’t function to maintain a certain level of water or to keep the water within a specified range of temperatures.  That kind of function seems unique to living organisms, the organization of which functions precisely to keep the internal state within certain parameters by resisting and exploiting external conditions.  It occurs to me at this moment that this description of function neatly explains the difference between a virus, for example, which functions in the first sense, and its bacterial prey which functions in the second. 

As I suggested, the gap between the two kinds of function largely concedes the resolved point.  Chemistry and physics can explain the one kind of function but not the other. 

John Dupré makes the case against reductionism by arguing in favor of “strong emergence”.  He makes the distinction between the whole (a lynx, for example) and the parts (organs, cells, subcellular machinery, etc.).  He denies that “the behavior of the whole is fully determined by the behavior of, and interactions between, the parts.”  My own version of his argument goes like this: precisely because the organism works to maintain its own internal states from succumbing to equilibrium with its surroundings and does so by resisting and exploiting the conditions it finds itself in, its behavior is determined in part by those external conditions.  Those external conditions are determined not only by the physical nature of the molecular components but by a very wide range of accidents.  The same air can be bitterly cold or blisteringly hot.  At the very least, biology has to consider those accidents and among them is the accidental arrangement of molecules into living organisms. 

The unavoidable conclusion is that biology cannot be reduced to chemistry and physics.  Keller is at least open to the possibility that the one might be reduced to the other and suggests some avenues by which that possibility might be explored.  I do not think she succeeds in making it look likely. 

Since I am of the tribe of Plato and Aristotle, I am allergic to reductionism in all its forms.  So I am pretty happy with this outcome.  One thing that both authors profess to believe in, however, is materialism.  I am not a materialist.  Moreover, I don’t think that Keller or Dupré are either.  I intend to demonstrate that in the next post.