Reductionism in BiologyDEACON DOUGLAS MCMANAMAN
The fallacy of reductionism is simply a habit of mind that involves transferring the way we know a mechanical artifact to the realm of nature, as if knowing a substance is like knowing a machine.
A machine is an artifact, and it is the sum of its parts. If a machine is "nothing but the sum of its parts", it is not a thing in itself, and indeed, a machine is not a thing in itself. Rather, it is a number of things (plastic, glass, rubber, copper, steel, etc). Now when a machine is under construction, the parts precede the whole. The whole, which is nothing but the sum of its parts, comes to be afterward. If we wish to understand a machine, we have to study its parts and how they function in conjunction with one another. That is why we open the hood of a car, to look at its engine and see how it works, etc. When we know the parts, their function, and how they work in conjunction with one another, we understand the whole, because it is nothing but the sum of its parts.
Now, although the parts precede the whole in the order of time, it is the whole that is prior to the parts in the order of perfection and completion (the whole always exists first in idea). There are no parts without a whole. Take a piston, for example. The piston is "what it is" only in relation to the whole, for it is a part of an engine. The whole exists first in the mind of the engineer; it came to be first, in his mind, through a final cause. We needed a vehicle that would take us from one place to another quickly, a vehicle that does not require human exertion, like peddling. The engineer conceives the whole idea of a vehicle that can run on non-human energy, first in a very general way. The parts only come into design later on as he begins to reason around how this vehicle will achieve the end that motivates him. Fuel is a component, so too wheels, a shaft that rotates, a piston connected to the shaft, etc. The parts are then manufactured, and the car is assembled in the end. The form of the whole is prior to the parts and the end product.
Reductionism or mechanism in biology is simply a method and mode of thinking that is transferred over to the realm of living substances, as if substances are nothing other than the sum of their parts. But, there are no parts without a whole determining the parts to be "what they are" in the context of that whole, and that is true even when it comes to artifacts, like the machine. The form of the machine exists in the mind of the engineer, but substances (whether living or non-living), have a nature, an intrinsic formal principle that renders them intelligible, determining matter to be "what it is" (i.e., a substance with ordered parts).
Let's ask the question: "Are you living because your cells are alive?" Or, are your cells living because you as a whole are alive? The answer is either a) you are alive because your cells are living, or b) your cells are living because you as a whole are living. Reductionists tend to choose the first alternative.
If your answer is b), the question now becomes: "What is the life principle of the whole that renders every part of you living?" And so, those who answered b) need not proceed any further.
But if the answer is a), then we need to proceed further. Let the same question now bear upon the cell. Hence, a) "is the cell living because its constituent parts (mitochondria, nucleus, reticulum, ribosomes, etc.) are living?" Or, b) are the constituent parts living because the cell is living? If the answer to this second question is b), then we need only ask the question: "What is the life principle of the whole cell that renders every part of it living?" And, if we answered b) to this second question, but answered a) to the first question, then we need to answer the following question: "Why does the cell as a whole have a life principle rendering all its parts living parts, but not the whole multicellular organism?"
But if the answer is a), namely, the cell is alive because its constituent parts are alive, then we need to proceed further. Let the same question now bear upon the constituent parts of the cell: a) "Are the cells' parts living (mitochondria, nucleus, reticulum, ribosomes, etc.) because their own smaller constituent parts are living (chromosomes, nucleolus, DNA, proteins, amino acids, etc)?" Or, b) are their own smaller constituent parts living (chromosomes, nucleolus, DNA, proteins, amino acids, etc) because they (mitochondria, nucleus, reticulum, ribosomes, etc.) are living?
If the answer is b), then we have a whole (i.e., the nucleus) that renders its parts living (i.e., chromosomes, proteins, etc.). But, if that is possible, why isn't it possible, from the beginning, that all the parts of a living organism (i.e., your cells and organs) are living by virtue of the whole organism (i.e., you)?"
If we continue to pursue our line of questioning, we arrive at a point at which we encounter parts that are not living. If not, that is, if we never arrive at non-living matter, then all matter is living, and chemistry is really biology, and in the end, there is no distinction between living and non-living things. All material things are living.
If we do, however, arrive at constituent parts that are not living, then we finally arrive at a level where something is alive, but not by virtue of its constituent parts. But how is it possible for a "whole" to be living while its constituent parts are not living, especially as the whole is said to be nothing but the sum of the parts. Part and whole would not be related; hence, the parts could not possibly constitute the whole. What would it mean to hold that a computer is alive but that no part of it is alive? In what way would these parts be parts of the whole?
A possible answer is that the whole possesses something that the parts have collectively, as a unity, but not individually.
But that is really another way of saying that the parts are what they are by virtue of the whole. In other words, it is simply another way of saying that the whole determines the parts to be what they are. Allow me to explain this further.
Obviously the cell, as well as every part of the cell, and every part of the parts of the cell, are highly organized. Organization is a kind of unity. It is the unity of a multiplicity. With regard to a living organism, unity belongs to the whole. The whole is one. It would not be a "whole" if it were not one. But it is the multiplicity that is reduced to a unity, not by the multiplicity, but by a single principle (the result is a unity, a single whole). An army, for example, does not reduce itself to a unity except through one unifying principle: one man has to step forward and organize the multiplicity into a unity, and this man, let's say, is the General. He's got the plan of action, which is why he operates from the headquarters.
If an organization loses its unifying principle, it becomes a non-unified multiplicity. It is "open" to being unified, and so a multiplicity that is unorganized is potentially organized, but not actually so. Hence, it is not actually intelligible (we can only understand something insofar as it is actual, organized, and one; a mere potentiality is unintelligible).
Multiplicity is organized and made intelligible through unity, as it is in the realm of quantity (i.e., number organizes a raw multiplicity through a unit of measure, such as a foot, or an inch, or a liter). Number is multiplicity organized. Duration (quantity of time) is organized when it is numbered by a unit of time, for example, a second. There are 60 seconds in a minute, and 60 minutes in an hour, and 24 hours in a day, etc. So, if one were to say: "Meet me back here in 72 hours", we'd know what he means. That duration of time is now intelligible and organized through number.
In the same way, a multiplicity is organized and rendered intelligible through a unity, and when organized, the multiplicity becomes parts of the unified whole. They (parts) are understood in reference to the whole. They cannot be properly understood in isolation from the whole (i.e., there are no "parts of an army" without an army). I only understand the multiplicity because it is organized and made intelligible through the unity.
I can consider a part of an organism in my mind, in isolation from the whole, but I do so only in my mind. If I were to really take a part out of the living whole (i.e., a kidney), it would cease to be a part of the whole and it would lose what it acquired as a result of being part of the whole. A kidney removed does not filter and excrete, a severed finger is not sentient. Both have become life at the vegetative level, at least temporarily, until they decompose completely into non-living matter.
Now, if I consider the parts in isolation from the whole (in my mind only), there is a sense in which I "kill" it intellectually. Doing so has its advantages from a scientific point of view, but it renders me unable to explain the nature of the thing, because I've "killed" it intellectually, so to speak – I've lost sight of the "whole thing" to which it belongs.
The reason I cannot do this in principle is that I can only understand a part to be "a part" because it exists in reference to the whole (without the whole, I could not know it to be a part). My knowledge of the whole is more certain and is prior to my knowledge of the part. Mitochondria are parts of the cell, and cells are a part of the animal (i.e., the cat). I know this because I know the cat, or dog, or man as a unified whole and I cannot understand "parts" without reference to the "whole"; for part and whole are correlative terms. Moreover, I come to understand mitochondria when I understand its function in relation to the whole, just as I understand what a liver is when I understand its function in relation to the whole. To consider a part in isolation and treat that part as a whole unto itself is to forget that one would not be able to grasp this "part" as a part, except in relation to the whole.
Within the context of the whole living organism, parts exist for the sake of the whole, that is, they have a function in relation to the whole. They exist for the sake of the integrity (integration or oneness) of the whole organism. Because of that, parts do not determine the whole, but are themselves determined or defined by it. If they exist prior to the "whole" in order to bring it into being in every way, they could not possibly be "parts", they are "wholes" unto themselves. To become parts of a larger whole, they would have to cease to be "wholes" unto themselves in order to become "subservient" to a larger whole, and this larger whole will be a qualitatively different kind of thing, defining the part and its function within it.
Consider the following analogy – fully aware that analogies are imperfect. A chess game has parts (pawn, queen, king, rook, knights, bishops, board, particular spaces). Each part has a definite function within the whole. A thing is identified (is what it is) through its function. It behaves a certain way, in a way that another part does not. For example, a bishop can only move diagonally, a pawn can only move one space at a time, except on the first move, a queen can move in any direction, as many spaces as one would like, etc. Take the queen out of the context of the whole game, and it is no longer a queen. It does not function as a queen. Imagine if someone were to reach over and say "I need that piece because we're playing checkers, and we are missing a piece". He takes the queen and uses it as a checkers piece. That queen is no longer actually a queen, it is actually a checkers piece, for it functions exactly as a checkers piece. It may still look like a queen, but it is only virtually a queen. It is "what" it is, and "what it is" is known through its activity, that is, the way it acts and the ends for which it acts. Moreover, when a pawn reaches the 8th rank in chess, it is no longer a pawn; it is a queen, although it still looks like a pawn. But it functions as a queen (it can move in any direction, as many spaces as the player wishes to move it). Because it functions as a queen, it is a queen.
The parts of a living organism behave in a new way within the larger system of an organized whole. That organized whole, we all agree, is a living whole. What is this living behavior of the "whole"? It is "living" behavior. What is that? A living thing is characterized by immanent activity, that is, self-perfective activity. That is essentially different than the behavior of non-living things: matter is inert; when it moves, it is moved by something outside of itself. A living thing is a whole that moves in a particular kind of way, it moves itself "from within": a dog runs, a cell divides and grows from within, a man thinks, imagines, and grows, etc. The fertilized egg starts off as a single cell, but begins to divide, gradually becoming more complex, developing its own parts from within itself. The whole is prior to the fully developed parts; for these parts come to be afterwards (i.e., spinal chord, heart, brain, legs, etc.).
A living whole is one that moves itself (grows) as a whole, it preserves itself (nutrition) as a whole, and it reproduces, that is, it begets a whole organism like itself, but other than itself. These are activities of the whole.
But non-living matter does not spontaneously become living matter. No one has been able to generate living matter from non-living matter. It hasn't happened, and it cannot happen.
As a rather simple example, let us say that no matter how much non-living matter one adds to the computer, it remains always a non-living whole, an artificial system. The additional parts are instances of accretion, not incretion. The computer is not one substance, but many non-living substances that remain "what they are" within the context of the whole. Your big toe is just as much "you" (living human tissue) as your finger is "you" (living tissue), but the plastic parts of my computer are substantially different (different substances) than the metal encasing my hard drive, or the rubber on the wires, or the copper, etc., that make up my computer.
Not only does every part of me share in my one human nature, every action I perform is an act of a single subject. It is not my eyes that see; rather, I as a whole see. My legs do not walk; I walk. The whole of me is alive, and I see by means of my eyes (part). I experience myself as a single, living entity. It is the same single organism that sees and runs and hears, etc. Every part of me is a part of "me", living and human (every part shares in the nature of the whole). My parts are not "wholes" unto themselves, even though we might consider them as wholes unto themselves, for the sake of doing science (i.e., studying the cell, or the eye, or the ear, etc.).
The computer's function of playing a movie, or opening and making available a word processing program, is not really an activity of the whole. In fact, it is not really an activity at all. There is no single thing that is acting. The function is really the result of a section of the artifact, which of course functions because the other parts are doing "their part", so to speak. The whole computer is not typing the essay. Rather, I am typing the essay, and the parts of this computer (each one of which is a distinct kind of substance) are organized in a way that permits this function (words configured on a screen that is lighted up, etc). The parts have all been made to function in conjunction with one another to produce a particular effect or effects.
And so artifacts like a machine have an "accidental" unity, an artificial unity, not a substantial unity, like you and I have. The car does not drive; rather, I drive the car. The function of the car is really an extension of my activity. The computer does not process, I do the processing by means of the computer. A non-living whole, like a machine, is really quite passive (inert), for it is nothing but the sum of non-living matter. In order to simulate activity, it requires a single subject who acts.
A further problem is that when we reverse the natural order of part and whole (as reductionism is wont to do), it is difficult to explain how a living organism has one life – and is thus one organism. For if these living parts (i.e., amino acids) cause these parts (proteins) to be living, and these living parts (proteins and other parts) cause DNA molecules to be living, and DNA molecules (and other parts) cause their nucleuses to be living, and the nucleuses and other parts cause the cells to be living, and there are billions of cells which cause the tissues in the organism to be living, and the tissues cause the organs to be living, and the living organs cause the organism to be living, in what way can we speak of one organism with one life? The organism is really nothing other than a countless number of living things. But I experience myself as one living thing. I also naturally regard other living things, like a horse or a dog, as one living thing, not many living things.
Going the other way, the organism (which is seemingly not a single living thing) is nothing other than its living parts, which in turn are nothing other than their living parts, which are nothing other than their living parts, which eventually are nothing other than their non-living parts (inert matter). It would seem, then, that living things, if they are nothing other than their parts, are, ultimately, not really living at all.
It seems that reductionism in biology leads to the conclusion that an organism is both a non-living thing and a multiplicity of living things at the same time.
Life, we argue, is a different kind (genos) of existence than non-living existence. A living thing is a different kind of being than a non-living thing. A non-living thing, no matter how complex, is not self-perfective, and it moves as a result of being moved by some extrinsic principle (a baseball is moved by a pitcher, a car by the wheels, drive shaft, crankshaft, pistons, exploding fuel, spark, current from battery, ignition, driver, etc). It does not engage in immanent action. It does not move itself, grow, nor transform non-living matter into itself, making it a living part of itself. The parts have been organized into an "artificial" unity, not a substantial unity, i.e., the tire is not substantially one with the whole car, but artificially one, for it remains a rubber tire. But I cannot point to your toe and say "that is yesterday's lunch, the veal and rigatoni you had".
Now one existing substance, a molecule or atom of a definite nature, might react with another and become something else entirely. I.e., sodium reacts with chlorine in a certain proportion and they become salt; they cease to be what they are to become something else entirely, salt is neither a metal nor a gas. It is a different kind of entity. It remains, nevertheless, a non-living thing. This new substance may react with another and undergo a radical change, and what we are left with is an entirely new substance, of a different nature altogether, with different properties. It remains, however, a non-living substance. At some point, the reductionist is going to say that we end up with a new substance that can move itself from "within", grow, and is capable of nutrition and reproduction. It is a living system, a new whole that organizes itself (self-organization).
But it is this leap to a new kind of existence that has to be explained. It is not enough to say that it is "more of the same" (i.e., another substantial change, like sodium and chlorine becoming salt); for it is not more of the same. A living thing is entirely and essentially different. If it were simply more of the same, then there is no essential difference between living and non-living things. "Living" becomes a name for something that is simply a more complex non-living thing (like a very complex vehicle).
But common sense knowledge that begins on the level of ordinary experience, where all science begins, indicates that it is something else entirely, of an entirely different nature. It is something that is self-perfecting, something whose activity is immanent, whose movement is from within (incretion, not accretion, as we see in crystals), which is why we look for self-motion (breathing or a pulse) to determine whether the body on the floor is alive or dead.
A cause or causes cannot impart what they do not have either individually or collectively, and a collection of non-living or inert matter remains non-living or inert matter. To be anything more, it has to be "organized" or "formed" into a particular kind of thing, a living thing. The form that is the organizing or unifying principle must inhere not in the mind of the engineer as it does in the mechanical realm, but in the thing itself, in union with matter, determining it to be what it is, reducing it to an actually living entity. Organization is distinct from matter. That is another way of saying that form and matter are distinct. Matter that is organized into a kind of thing that is essentially different from inert matter is what we mean by a living organism.
But there is no self-organization without a "self", a thing, and a thing cannot form or organize itself unless it has "form" – otherwise, it would give to itself what it does not have, which is to get something from nothing. Potency does not reduce itself to actuality except by something already in act; multiplicity does not number itself, but is numbered by virtue of a principle, a unit, and disorder does not reduce itself to order except by a principle of order. To deny this is to equate something with nothing.
Organization is rooted in a principle, a unifying principle, and a unit is always distinct from the multiplicity, as order is distinct from disorder, or as determination is distinct from indeterminacy. The life principle is not matter, it is distinct (not separate) from matter. Hence, it is a non-material principle, a form, an intelligible configuration, and wherever there is form there is unity. Without unity, there is only multiplicity unorganized and unintelligible. The form of the living substance, distinct from matter but not separate, is what we mean by the soul.
Finally, let us ask the question, a) "are you alive because you are breathing? or, b) "are you breathing because you are alive?"
If the answer is a), it would suggest that a living thing is its "activity". You might agree and point out that certain activity, such as metabolism (the interplay between catabolism and anabolism) constitutes the thing, such as the cell; for without metabolism, the cell is dead. Hence, a cell is alive because there is a metabolism. Since metabolism is a living activity, it follows that activity (metabolism) determines the "thing" (i.e., the cell). The "thing" is primarily an activity – or series of activities (metabolism, breathing, growing, reproducing, etc.).
If a thing is nothing other than its activity, then there is no underlying or enduring "thing", only various activities, like metabolism, breathing, etc. The "thing", i.e., the organism (i.e., dog) is a name given to the final product. But there is no entity as such, only activity. In other words, there is a predicate (growing, breathing, eating, etc.,) but no real subject. For example, "John is a thing that breathes" is a misrepresentation of the facts. There is no single thing, "John". The latter is but a name.
If the answer is b), then "things act". In other words, entity precedes activity. This thing "barks and runs" because it is first and foremost a dog that has a single life principle, determining it to be the kind of thing it is; that thing swims and breathes through gills because it is first and foremost a fish, which is a single thing that has a life principle.
The cell metabolizes, but metabolism is a self-perfective activity, which means it is an activity of a cell (entity) carried out for the sake of its own perfection. Self-perfective activity presupposes a subject of the activity that is distinct from its activity.
Activity is the realization of a thing's capabilities. There is no action without a subject to carry out the acting. It is the hand that waves, it is the finger that wiggles, it is the "person" that thinks, it is the organism that metabolizes, it is the cell that divides, etc. And that is why we ask the question: "What" is it that is growing? "What" is it that is breathing? When we ask such questions, we are asking: "What is the subject of those activities?"
And so, when a person shakes hands with or hugs another, he is not shaking a shake, or hugging a hug, he is shaking a hand, or hugging a person. If a person sneezes all over you, he does not sneeze all over breathing, or walking, or growing; he sneezes on you.
Deacon Douglas McManaman. "Reductionism in Biology." CERC (November 2010).
Printed with permission of Deacon Douglas McManaman.
photo: Gary Tonhouse
Doug McManaman is a Deacon and a Religion and Philosophy teacher at Father Michael McGivney Catholic Academy in Markham, Ontario, Canada. He is the past president of the Canadian Fellowship of Catholic Scholars. He maintains the following web site for his students: A Catholic Philosophy and Theology Resource Page, in support of his students. He studied Philosophy at St. Jerome's College in Waterloo, and Theology at the University of Montreal. Deacon McManaman is on the advisory board of the Catholic Education Resource Center.
Copyright © 2010 Douglas McManaman
Not all articles published on CERC are the objects of official Church teaching, but these are supplied to provide supplementary information.