Can Biologists Speak of the “Whole Organism”? A Conversation
Stephen L. Talbott
From In Context #22 (Fall, 2009)
Molecular biology is now facing a historic overturning of its foundational mechanistic assumptions. At issue is the question, With what kind of thinking can we understand the living organism? The loss of the gene as all-sufficient explainer of the organism together with the disorienting deluge of disconnected detail yielded by today's sophisticated, molecular-level analytical techniques, has tended to deprive researchers of any coherent picture of the living creature as a whole. Yet, as we will see below, the unity and distinctive character of the individual organism are continually assumed within all biological explanation. Can biologists make this unity and character an explicit and legitimate object of their science?
In order to bring out some of the issues in a rather more informal and conversational manner, I have cast my remarks in the form of an interview. The interviewer and cross-examiner is an emeritus professor of molecular biology. While his underlying scientific views are more or less conventional, his life-long penchant for exposure to wider worlds of thought has given him a somewhat softer and more rounded perspective than is common among his colleagues. The subject of the interview is a younger naturalist-turned-philosopher of science (whom I am inclined to think of as a woman). She combines within herself traits of a number of biologists and philosophers who have stood outside the mainstream of biological thought during the past several decades.
MOLECULAR BIOLOGIST: Perhaps you could begin by telling me a little about your current work and interests.
NATURALIST: I've recently been looking at the attempts by early twentieth-century biologists to find a holistic framework for their experimental investigations. One of the more striking figures I've stumbled upon is the British biologist, E. S. Russell, who wrote back in the 1930s and 1940s. His little volume entitled The Directiveness of Organic Activities concerned the “purposiveness” of living processes. Russell offered one example of this purposiveness after another, in detailed chemical, physiological, and behavioral terms. In an earlier book he had argued strongly for the unity of the organism and against a one-sidedly analytical approach to living things. Physics and chemistry alone, he argued, could never give us an understanding of the organism.
Yes, I'm aware of the heritage you speak of. My younger colleagues are usually surprised to hear that some form or other of purposive, or teleological, thinking was almost universal among the great names in biology — Darwin, for example — and that it remained common up through the first half of the twentieth century.
We don't teach our students much history, do we! In any case, a central conviction of many of those earlier researchers, tracing back to Immanuel Kant, was that the biologist has no choice but to take as given the apparent purposiveness, the defining organization and pattern, the coherent and unified functioning, of the living organism. In their view, the proper and necessary search for explanatory mechanisms always presupposed the directed activity of the whole — directed activity that, as such, can't be fully captured in the usual causal and mechanistic language.
As you probably realize, it was the embryologists and developmental biologists who resisted most firmly all attempts to reduce the organism to mechanism alone.
It's hard to ignore the appearance of directed activity when you're watching the life of an embryo unfold into that of a mature organism! Organ primordia are laid down in the embryo long before the mature organs can assume their functions. Everything in the developing organism proceeds “with a view toward” some end.
And so Russell held that the organism — already as a fertilized egg — is an intricately patterned whole directed toward the actualization of its unique potentialities. This directed activity, he claimed, can be described adequately only with reference to the completeness of the whole. Without such reference — without acknowledging the organism's constant drive towards a normal and specific end or completion - we lose any distinctively biological meaning amid the bewildering flood of causal detail at the physical and chemical level.
But while sympathy for such views may not have been uncommon in Russell's day, it finally evaporated during the second half of the twentieth century — and perhaps for good reason, given our progress in understanding the genetic mechanisms involved in the development of the organism. The way you describe Russell, it sounds as though he believed in some sort of entelechy or vital force. You probably know better than I that biologists now thoroughly reject such mystical notions, even if we haven't yet finished the work of purging them from our language. In any case, it's anathema to speak of vital forces. But perhaps Russell was just innocently expressing a poetic bent of the sort popularizers often resort to in order to make science more palatable?
He was no popularizer, but a highly respected biologist of his day. He was hardly given to poetry, and remained dead-set against entelechies and vital forces. He respected physical causation at least as much as the next person. He just wanted the fullest possible understanding of the organism as we actually find it through careful observation, without filtering that observation through an externally imposed creed, whether vitalist or mechanistic.
Sounds like unimpeachable science. Did he stick to it?
Yes, I think he did, but his science would have a strange ring to it today. The problem lies in that unfamiliar emphasis on unity, wholeness, and purpose. Not anything very like conscious human purpose, by the way, but analogous to it. “Biological purpose” he called it. A purpose that's evident even in the activities of growth and the development of form. Like the classic acorn “striving” to become an oak.
Russell may disavow vitalism, but the question is whether he can in fact avoid it. Can he point to the special directive force that drives this striving?
He really does scorn all talk of special forces, vital or otherwise. When you read his descriptions of wound healing or insect behavior or temperature regulation in mammals, what you get is the usual chemical, physiological, and behavioral descriptions. He's inviting you to see, not some special force, but simply what's implicit in the descriptions themselves - what holds them together and makes sense of them. They are always assuming a certain larger, contextual unity, as if the goings-on were integrated and coordinated “from above.” The lower-level processes, which we describe in chemical and physical terms, both enable and condition the higher significance but never explain it — because we have defined those processes with a language of analysis and isolation that excludes anything like coordination, context, and purpose.
I think you need to give me a more detailed example than just “acorn and oak.”
How do wounds heal? The first of the many examples in Russell's little book is perhaps the easiest to relate. He cites contemporary work on wound healing in the blood-sucking hemipteran bug, Rhodnius prolixus. Beneath the hard cuticle of this insect is a single layer of epidermal cells on top of a basement membrane. If you excise a tiny sliver of these tissues, you set in motion a remarkable series of healing processes.
To begin with, the neighboring epidermal cells become activated and migrate toward the edges of the cut, while red blood cells accumulate in the same area beneath the basement membrane. Having congregated at the site of injury, the epidermal cells then spread into the excised area. In simple cases, where the wound is small and the basement membrane intact, the wound is quickly covered by a few cells that are spread excessively thinly, with cytoplasmic bridges connecting them. As more cells follow these, they become more and more crowded until the normal density is reached, at which point the spreading ceases. After the migration, cell division continues, but mainly in the now-thinned area from which the migrating cells came. As for the cells that spread over the cut, they initially form a layer several cells thick, but the normal one-layer-thick epidermis is slowly restored through selective degeneration of the unwanted cells in the lower layers. Any overcrowding around the margins of the wound resulting from the migration of cells is similarly relieved by the degeneration of superfluous cells.
It's good to imagine this highly choreographed activity concretely and in detail. There's clearly a goal — a norm which the various processes aim at reestablishing.
Most interesting, however, is what happens when the nature of the wound is varied. For example, using heat, it's possible to destroy a group of epidermal cells without injuring the cuticle. In this case there is little migration toward the burn margin from surrounding areas. Rather, the existing cells at the immediate margin begin to fill in over the layer of burned cells — and they do so through multiplication rather than migration. Compare this with the incision, where the injured area was filled to “overcrowding” by migration, with subsequent die-off of excess cells in the injured area. And whereas, with the incision, cell multiplication occurred in the more distant regions from which migration occurred, in the case of the burn, multiplication takes place in the injured area.
There are other variations, but you get the point. This particular insect was chosen, by the way, because it presents an unusually simple situation. Nevertheless, it seems that the only general rule governing the various healing processes is that they aim at the restoration of normal form and functioning. Depending on conditions, there can be a remarkable variation of means toward this end. The point is not at all that there are no lawfully connected physical processes every step of the way, but only that the appeal to immediate causal factors does not give you the coordinated, goal-directed character of the overall goings-on, where every different situation may provoke a somewhat different way of reaching the same goal. And when the goal is reached, cells stop migrating or multiplying, and excess cells die off — whatever is necessary for the recovery of the norm.
As the scientist who did this research, Sir Vincent Wigglesworth, put it, there is clearly an overall pattern of regulation here which cannot be explained strictly in terms of the specific chemical and physical responses he took such pains to identify. Those responses are somehow coordinated with a view to a norm or goal. It seems that, observing this, the scientist should at least acknowledge it, as Wigglesworth was still able to do in the 1930s. I'm afraid no technical journal today would print what he could so freely write back then.
That's helpful. I've been impressed by such descriptions myself. But while it's true that Wigglesworth probably couldn't get a technical journal today to accept his remark about regulation requiring a different sort of understanding, it's hardly the case that we molecular biologists have avoided all appeal to regulatory purposes and goals. Sometimes it seems we do nothing but invoke such goals. Genes have long been said to be “for” the achievement of certain end states called “traits” — this despite the fact that the causal pathways between gene and trait are almost completely unknown. But we differ from Wigglesworth in one regard: we're convinced that, whatever the ultimate causal mechanisms turn out to be, they will give us all the explanation we need. And this remains true even though everyone now disowns the simplistic, “gene-for” language. We recognize that an incredibly complex investigation lies ahead of us, but, in the end, our science will be a science of physical causes alone, without mystical-sounding “wholes” and “goals” and “purposes” You don't believe this?
No, I don't, although I reject the reference to mysticism. Moreover, I would think the loss of the falsely imagined gene, with its all-purpose explanatory powers, would by now have given molecular biologists some reason for open-mindedness on the subject. The ongoing revolution in epigenetics is all about the modulation of gene expression by countless regulatory factors, the modulation of those regulatory factors by yet other factors, and so on and on in an endless and confounding pattern of mutual interaction. We're being overwhelmed by the very richness of fact and data at our disposal. There seems little hope that analysis of local causal interactions will enable us to understand what's going on in the larger, functional sense — the sense required, for example, in order to get a grip on wound healing.
It's rather as though we were trying to understand a democratic society by analyzing the physical movements and material exchanges between individuals on the street or in the home and office, without reference to the democratic ideals and all the other supporting ideas at work in the society. Human ideas, of course, are often conscious ideas. But we know that they also work subconsciously, where they become more deeply interwoven with our bodily existence, sometimes as symptom. We can recognize this play of an ideational content down through increasingly organic or biological levels. Animal instinct is a kind of half-way house. But where is the stopping place? Nowhere. It's idea-like all the way down.
There's an amazing coordination in the living cell, which is no less meaningfully patterned than a democratic society. Yet our explanatory tools are designed to rule out any reference to the meaningful activity of the whole — to rule out characterizing its way of being, its integrity, its specific nature. The unity, of which the coordination is an expression, simply isn't looked for in its own terms. Why? Because that unity is more like a dynamic and imaginal idea than a collection of parts or facts or material causes.
I'm afraid you'll have to explain that further.
Think of the word, “organization.” When we refer to the organization of the chromosome or the organization of the cell's nuclear architecture, what are we referring to if not a meaningful context — a context enabling us to say that this or that part is in its proper place and playing its proper role? We're drawing upon judgments about a norm — about an expected overall pattern or functioning or meaningful collaboration of things — and without such judgments, our usual ways of describing the details make no sense. The context enabling the judgments is what Russell means by a “whole” — or, rather, a relative whole, for every whole is in one way or another caught up in a larger whole.
A context is not some thing. It's what gives things their significance, a meaningful place within a larger picture. It's more like an organizing idea than some sort of organizing stuff. And every time we use this humdrum-sounding word, “organization,” we're drawing on the capital contained in that assumed idea. But we haven't earned the capital; in fact, we deny its existence by pretending that our scientific explanations are strictly about some kind of idea-less substance.
I can follow you, if only part way. In fact, I think I can reinforce your thought a bit. I once made a rash attempt to teach a course on philosophy and biology, and one of the things I asked the students to do was to imagine living cells thrown into a blender and homogenized. Then I told them to try applying the routine terms of their biological vocabulary to this "soup." Would they say one group of molecules was signaling to another? Did particular portions of the soup have well-defined functions? Were there errors occurring in the molecular activities - the kind of errors we speak about, for example, in gene transcription? If they spooned some of the soup into a second bowl, and some of the second bowl into a third, would they speak of anything like biological heredity between the soup “generations”?
I wanted them to become aware of the assumptions they unthinkingly brought to the living cell — assumptions that didn't sit at all comfortably with their casual references to “mechanistic explanation.” Putting it in your terms: I wanted them to understand how they were continually assuming meaningful context and biological purpose. Errors are errors only relative to some taken-for-granted outcome. To speak of the function of a cell or organ or organism is, as you have pointed out, to speak of a norm and a goal.
An excellent lesson! Did the students get it?
I'm not so sure. They certainly saw the immediate logical point. But for most of them, I suspect, it remained a mere point of logic; it didn't provoke any profound reflection about what they were doing. They had these marvelously effective methods to work with in the laboratory, and these gave them a kind of closed and gratifying world of precise, calculable results. Relative to those results, quibbles over what their language really meant didn't seem very relevant.
When I was young, many older biologists were aware of the problems inherent in their descriptions of organisms. One or two of them even referred back to Kant. They knew the issues would have to be resolved in one way or another. Or would resolve themselves: it was often suggested that, with more adequate technical work, the difficulties would simply disappear, so that all implicit reference to wholes and their directed activity could be dispensed with. Nowadays I don't think very many researchers ever think about such things. We don't train them for it. Which isn't to say they lack visceral responses. I can easily imagine, for example, the protests of my colleagues against your "organizing idea"; they would much prefer “organizing stuff.” The “stuff,” of course, is — or at least was — DNA.
Yes. But then they begin speaking about DNA as a computer program, and they throw around terms like “code,” “message,” “information.” Unable to get along without the organizing idea, biologists smuggle it in through the back door, trying not to notice it. But the fact remains: a program takes shape in the programmer's mind. Its physical implementation is almost incidental; it might consist of pits in an optical disk, magnetized locations on a tape, or just about anything else. The material side of it really doesn't matter, just as the ink marks on the page of a book are purely arbitrary; they can take many forms as long as you know the language — that is, as long as you know how the marks map to an inner, ideational content.
You'll probably remember how, during the Human Genome Project, Walter Gilbert predicted that you and I will pocket a CD carrying the code for our personal genomes and say, “Here is a human being; it's me!” Clearly, the chromosome as physical stuff didn't matter much; the only thing that counted was the code — a pure, conceptual abstraction that could exist on a CD just as well as in flesh and bone! However, if this is what you mean by your organizing “idea” . . . well, it almost sounds as though you're wanting to take leave of the physical world!
No, no, you've quite misunderstood me. The material chromosome does matter! If there was ever any doubt, then all the current work in epigenetics certainly removes it. It almost looks now as if the physical gesturing of the chromosome is more central to gene expression than any fixed and abstract code. My point was simply that, when you try to ignore the relational context with its organizing idea — the context that invests those chromosomal gestures with their particular meaning — you end up supplying the idea in an unconscious and highly fanciful manner.
No, I want the physical chromosome, but I also want to recognize the functioning, the organization, the context, that shapes its performance. A term like “organization” is routine science-speak, while “idea,” or “meaning” or “contextual significance,” as I'm using those terms, sound discordant if not downright alien to science. And yet, when you look at the actual usage, “organization” and “idea” are more or less the same. So why do they have such a radically different “feel” for us, with one of the words being commonplace and the other scarcely acceptable? Why does the “organization” that accounts, or helps to account, for the acorn's becoming an oak — an organization that can hardly be unlinked from concepts with ideational reference such as “type” or “kind” or “archetype” — why does this word seem so comfortably scientific and familiar, whereas the “idea” that carries much the same meaning raises the specter of vitalism or mysticism? What are we trying to hide from ourselves by reviling “idea” and reveling in “organization”?
I think there are two problems here. The first is that appeals to “holism” and the “idea of the organism” have historically been associated with some sort of mystical orientation or vitalism — and for good reason. There's just no way, using the tools of science, to proceed with wholes as such. What can you do if you are handed a whole, whether it be an acorn or an oak — or a monkey? I think you will only be able to do what scientists already do: begin to observe particular details, analyze, dissect, calculate, put cause and effect together. If you try to do anything else, you end up with mysticism. What else is “the idea of the oak”? Maybe the value of a word like “organization” is that somehow it distracts us less, and doesn't so easily tempt us in the direction of fruitless speculation. And — can't you grant this? — maybe we really will someday reach the point in our understanding where we can use such a word without any hidden appeal to the ideational meanings you are so exercised about.
Let's get to the heart of the matter. A vitalist is someone who claims that hitherto unknown, and perhaps nonphysical, causes produce effects in the organism other than those we know of in chemistry and physics. I don't see how, when pressed, you will be able to avoid calling up such causes, or forces. You've already said that chemical and physical forces cannot account for the regulative unity of the organism. Won't your — “organizing idea,” or something like it, have to become the missing force?
But I never suggested there was a missing force. Certainly an idea can't be thought of as a physical force or as a cause in the normal scientific sense. Think of the mathematical ideas we employ in the analysis of masses subject to gravity. Will anyone mistake those ideas for the force itself? No — but we do want the ideas to be faithful to reality. The conceptual, mathematical character of gravitational masses needs to be really there in the world. That's why we can discover it. And so, too, the recognizable and describable character of the acorn on its way to becoming an oak tree is really there. That's why we can recognize and describe it, distinguishing the oak's entire, unified way of presenting itself — its way of being — from that of the willow or birch. We don't accuse the physicist of mysticism because he insists on understanding phenomena with reference to a mathematical idea. Why should the biologist be guilty of mysticism when she finds her understanding of an organism inevitably taking the form of an imaginal and descriptive idea that captures a way of being?
Of course we don't mistake a mathematical description for the force it describes. But the mathematical description works because there is such a force waiting to be described. What force or law or other reality corresponds to your oak's “imaginal idea” or “way of being”?
You could perhaps speak of a law, although I'm not sure what is so objectionable about sticking with “idea” or “way of being.” In any case, our aim as scientists must be, first of all, simply to describe what we observe. The unified functioning of the organism is recognized and acknowledged in one way or another by everyone, as your classroom experiment with the soup of molecules showed. That describable functioning is the law, if you must have a law.
The fact that we can't, as yet anyway, see behind the law to some deeper reality is no more a criticism of its proper scientific description than is the fact that we have no clue about what lies behind the lawful mathematical ideas of physics. Didn't Richard Feynman remark once that no one knows what energy is? The same can be said of forces such as gravity. But we do know what we observe, with its characteristic and ideal lawfulness. A physical mass respects the strictly mathematical lawfulness we speak of as “gravity,” and the acorn respects not only that lawfulness, but also, on a different level, the lawful way of the oak.
I can see you are determined to avoid the stigma of vitalism! But, whether you are a vitalist or not, it seems to me that everything you are saying runs into the second problem I alluded to. While our description of living things as purposeful or as striving to realize their own distinctive character has a certain validity, I don't think it's the kind of validity you're asking for. Yes, Darwin and biologists generally are notorious for using the language of purpose — teleological language. Protective coloration is "for the purpose of" defense against predators, large leaves are “for the purpose of" catching more sunlight, and so on. And it's the same at the level of cellular chemistry. There's justification for this, and — as I said a moment ago — the expectation is that eventually we will be able to deflate this teleologically loaded language, reducing it to the purely mechanistic language that must finally capture the truth — the whole truth, if you like.
But — and this is what I had wanted to say before — we already have, in the broadest sense, a mechanism for deflating teleological language. When we speak of the acorn as if it had an inborn purpose, the key words are “as if.” It does look that way to us, and it's okay to speak that way - as long as we realize that we're only speaking “as if” the purpose were there. There's a good explanation for this appearance, but that explanation lies in what we now know is the ultimate blind and purposeless mechanism — the mechanism of evolution. Evolutionary adaptation is the means by which the organism comes to look as if it were “made for” meeting the various requirements of its life. In a very real sense it is made for that purpose, because evolution, as some have put it, is a “consequence-oriented mechanism.” Mutations persist only if they turn out to serve the purpose of survival, so the organism seems to be full of purposive processes. But the mutations were nevertheless random developments within perfectly mechanistic processes. It all looks like teleological magic, but the magician is none other than natural selection.
Notes on the Conversation (So Far)
In case you forgot to take notes, here are some points to remember, quarrel with, or otherwise reflect on:
Teleological (functional, goal-oriented, purposive, directive) language has been positively embraced as necessary throughout nearly the entire history of biology.
Such language assumes a directing and coordinating primacy of the whole organism over its parts.
Teleological language, though widely disavowed today, remains a stubbornly universal feature of all biological description. It is reflected in such routine terms as “organization,” “function,” “signal,” “expression,” “stimulus,” “response,” and even “mechanism,” since machines are always constructed so as to embody a function or purpose.
Purpose in the relevant sense need not be human-like or conscious, but can manifest as biological purpose in, for example, growth and the development of form.
The idea or character or way of being of an organism is not a vital force. It is no more "mystical" than are the mathematical ideas, or laws, by which we describe the behavior of physical systems under the influence of gravity.