Is a Whole Organism More Than the Sum of Its Parts?
September 23, 2011 1 Comment
Here is the second part of the essay series I started looking at yesterday, about the complexity of living things and ultimately pointing towards an argument for a new type of scientific explanation for life. The article is called The Unbearable Wholeness of Beings, and unfortunately it started being disagreeable to me from the get-go. If you’re interested in the idea that there may be more to life than chemical processes – whether in agreement, disagreement or uncertainty – you should check it out.
(Update: here is my post on the third essay.)
This post is much longer than the norm – I had the “yelling at the TV” effect where I couldn’t help but disagree as I was reading along, so I thought I’d share my opinions along the way.
Animals and plants are a long way from rocks and clouds, and also from automobiles and computers. The need to point this out today is one of the startling aspects of the current scientific landscape. It is true that the concept of “vitalism” has been problematic in the history of biology, but no less so than “mechanism.” The two problems are in fact devilishly intertwined. We will never get straight about vitalism if we do not also get straight about mechanism. And until we sort through the associated confusions, we have little hope of meaningful conversation about many of the perplexities vexing biologists today…
Here, then, is my question: Are you and I machines? Are we analyzable without remainder into a collection of mechanisms whose operation can be fully explained by the causal operation of physical and chemical laws, starting from the parts and proceeding to the whole? It might seem so, judging from the insistent testimony of those whose work is to understand life.
The article goes on again into the depths of cell biology. The last article explained these complexities to show that the field of biology is not what it used to be, and that scientists have discovered that things are not as easily explained as they once thought. This article unfortunately seems to be making similar points but to the end of making a lower-level “god of the gaps” argument – not for religion, but for an explanation of life that doesn’t conform to modern science.
The fact that I called it a god of the gaps argument shows chiefly what I think is wrong with it; it criticizes conventional explanations without offering any evidence for an alternative, and assumes that a current failure to fully comprehend something indicates a permanent failure.
The author makes a few arguments, of which I’ll only excerpt a morsel:
Sometimes, in fact, the biologist’s language may reach beyond your own intuitions, as when two researchers say that we might gain “insights into the ‘thought’ processes of a cell” (emphases added here and in the following). The same two researchers describe signaling networks as the “perceptual components of a cell,” responsible for “observing current conditions and making decisions about the appropriate use of resources — ultimately by regulating cellular behavior.”
He claims that this way of describing cellular behaviour betrays the fact that there’s clearly something going on beyond the supposed physical reactions. However, anthropomorphizing things is very common human behaviour; in this case called the pathetic fallacy. It’s the use of language that makes most sense to us; it doesn’t indicate anything about the topic actually being studied.
By virtue of [their] coordination, every local or partial activity expresses its share in the distinctive character of the whole. The ability of the organism to pursue its own ends amid an ever-shifting context means that causal relations become fluid and diffuse, losing all fixity. They are continually subordinated to, or lifted into service of, the agency of the organism as a whole…
Despite the countless processes going on in the cell, and despite the fact that each process might be expected to “go its own way” according to the myriad factors impinging on it from all directions, the actual result is quite different. Rather than becoming progressively disordered in their mutual relations (as indeed happens after death, when the whole dissolves into separate fragments), the processes hold together in a larger unity. The behavior of the whole “is infinitely less variant from moment to moment than are the momentary activities of its parts”…
It turns out, then, that less change is what shows the whole cell or organism to be more than the sum of its parts. It is as if there were an active, coordinating agency subsuming all the part-processes and disciplining them so that they remain informed by the greater unity. The coordination, the ordering, the continual overcoming of otherwise disordering impacts from the environment so as to retain for the whole a particular character or organized way of being, expressively unique and different from other creatures — this is the “more” of the organism that cannot be had from the mere summing of discrete parts. The center holds, and this ordering center — this whole that is more than the sum of its parts — cannot itself be just one or some of those parts it is holding together. When the organism dies, the parts are all still there, but the whole is not.
Basically: how do cells organize themselves, even when they’re constantly changing? If someone asked me this, I’d immediately say: using constant feedback. Cells are in constant communication with each other, and they’re changing based on their environment. He points out:
A given cell can be moved from one place to another, resulting in a completely different fate for that cell within the developing organism. What might have been part of a hand becomes instead part of a leg. This indicates that the cell’s fate is determined “on the fly”: a governing dynamic disposes of each part according to the needs of the overall pattern. The developing relations between the individual cells are more a result of than a cause of the order of the whole.
So a cell will find a way to be useful to the organism, even if it’s plucked out of its original niche. Why wouldn’t “the developing relations between the individual cells” be able to explain that? A “hand” cell gets feedback pointing to the fact that it’s now in the “leg” environment, and it adapts accordingly. Everything is built relative to everything else.
Say you have a line of people with their eyes closed, crouching to various degrees so that the line has a height gradient. Someone from the tall part of the line is plucked out and inserted in a short part of the line; he should be able to quickly feel how high the people around him are standing, and adjust accordingly. Does he need some outside organizing force to do so? Is this “line with a height gradient” more than the sum of its parts? No – conventional relations between cells (or people in this case) are enough to explain the phenomenon.
And finally, he discusses the flaws in biology’s view on intracellular regulation, such as the idea of DNA as the control center of the cell:
Before concluding, it remains only to show ever so briefly what happens when you mix the language of organic coordination with that of mechanistic control. It’s not a pretty sight. A paper that recently landed in my e-mail inbox, otherwise very worthy, serves as well as any to illustrate the situation. It concerns the p53 protein:
The tumor suppressor p53 is a master sensor of stress that controls many biological functions, including [embryo] implantation, cell-fate decisions, metabolism, and aging…. Like a complex barcode, the ability of p53 to function as a central hub that integrates defined stress signals into decisive cellular responses, in a time- and cell-type dependent manner, is facilitated by the extraordinary complexity of its regulation. Key components of this barcode are the autoregulation loops, which positively or negatively regulate p53’s activities.
We have, then, a master sensor that controls various fundamental cellular processes, and yet is dependent on the signals it receives and is subject to “extraordinarily complex” regulation by certain autoregulation loops. While all these loops regulate p53 (some positively and some negatively), one of them, designated “p53/mdm2,”
is the master autoregulation loop, and it dictates the fate of an organism by controlling the expression level and activity of p53. It is therefore not surprising that this autoregulation loop is itself subject to different types of regulation, which can be divided into two subgroups.
So the master controlling sensor is itself subject to a master controlling process (one of several regulatory loops) that dictates the fate of the organism. But this master loop, it happens, is in turn regulated in various manners (the author goes on to say) by a whole series of “multi-layered” processes, including some that are themselves “subject to direct regulation by mdm2” — that is, they are regulated by an element of the regulatory loop they are supposed to be regulating.
I can hardly begin to describe the stunning complexity surrounding and supporting the diverse performances of the p53 protein. But it is now clear that such “regulatory” processes extend outward without limit, connecting in one way or another with virtually every aspect of the cell. The article on p53 makes an admirable effort to acknowledge and summarize the almost endless intricacy and contextuality of p53 functioning and, with its language of mechanism and control, it does not differ from thousands of other papers. But that only underscores the undisciplined terminological confusion continuing to corrupt molecular biological description today. When regulators are in turn regulated, what do we mean by “regulate” — and where within the web of regulation can we single out a master controller capable of dictating cellular fates? And if we can’t, what are reputable scientists doing when they claim to have identified such a controller, or, rather, various such controllers?
Here again the author gets caught up with our use of language. Look at a boss. Employees go to a boss for instructions – that’s why the call him the boss. But a boss also makes decisions based on what feedback he’s receiving from employees. Employee A, we’re out of product 1? Employee B, go order some more. The boss is not any less of a boss just because he responds to feedback – in fact he’d be pretty useless if he didn’t, the same way a regulator of anything would be pretty useless if it didn’t respond to feedback as well.
How do biologists find regulators? They find the thing that, to a large degree, affects a lot of other things. You only have to look at the quoted intro to the paper to see this: “The tumor suppressor p53 is a master sensor of stress that controls many biological functions…. The ability of p53 to function as a central hub that integrates defined stress signals into decisive cellular responses…” (bold mine). What makes this an important regulator, then, is the fact that it integrates signals from many sources and relays signals to many destinations – like a boss.
Sure it is, in turn, regulated by other things, and its “orders” probably need very specific sets of conditions in order to be received and carried out, but that doesn’t take away from the fact that it has a distinct nature as a “central hub” – so we call it something distinct, like a master regulator.
In conclusion: clearly, I don’t agree with the author’s idea that the modern view of cell and molecular biology is insufficient to explain the nature of life. I think the main problem with his arguments is, again, his “god of the gaps” reasoning, throwing his hands up in the air because cell biology is really, really complicated. I encourage you to read it on your own though to see what you think, and let me know what thoughts you have. Tomorrow I’ll read and post about the final essay in the series, “What Do Organisms Mean?”. (Update: that post is here.)