Rediscovering Life

The Paradox in “Explaining” Form

Stephen L. Talbott

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Posted: June 15, 2013   (Article 3)

Interestingly, that same article in Science" (see my previous posting) goes on to pose some of the “mysteries of development”, one of which is this:

“The shape of your nose? That’s all written very precisely somewhere in some form,” Lawrence says. “We have no clue where”.

Do you hear the question? Where do we find the form in which the shape of the nose is recorded? This way of putting it is fortuitous, pointing us to a much ignored truth: we cannot explain form in terms of anything other than form. To ask how any given form or shape is achieved during an organism’s development is always to ask about a set of transformations. We look for how the earlier forms — based on their own unique potentials and those of their life context — re-shape themselves (and are re-shaped) into the later ones.

So long as we are addressing the question of form, our explanations must remain within the realm of form. Actually, it’s interesting to ask whether any explanation of anything can proceed without form of some sort being central to the explanation, whether explicitly or implicitly. (And also: what are we apprehending, when we apprehend form? Why does the pursuit of that question usually end up touching the realm of aesthetics? Isn’t this because form, never perfectly mute, is always expressive or gestural, requiring cognitive powers on our part that go beyond the quantitative? And what does that tell us about the true nature of a biological science that is irreducibly a science of form, whatever else it may be?)

Of course, many biologists say they are looking for an “encoding” of form in the linear DNA sequence. But this is an impossible way of speaking. What we actually witness is the participation of DNA in the well-formed developmental processes largely impinging on it from elsewhere. We find ourselves looking at, among other things, dynamic chromosomal forms (see the June 10, 2013 posting); shifting bioelectric fields; spatio-temporal signaling patterns; and the kaleidoscopic play of physical forces among tissues, organs, the extra-cellular matrix, immediately surrounding cells, internal membranes, and the various filaments and tubules making up the cytoskeleton.

All of which is to say: form isn’t encoded in DNA or any paticular collection of molecular components, but in the cell and organism as a whole.

The truth is right before our eyes. The one-celled zygote is already a living organism. We see it going through a wonderful, almost magical series of coherent metamorphoses, with streams of dividing cells moving to their appointed places, and every developing cell lineage emerging through the evolving, changing life of ancestor cells. As it grows, the organism never sets about building cells anew, from a blueprint, in the way we build machines. It is never doing anything other than transforming itself. One form merges into another in an intricately ordered, yet plastic and adaptable, fashion. Is there any reason to doubt that we are watching a lawfulness of form?

The difference between the early embryo and the mature organism is that the form of the embryo is more fluid and dynamic. It is more a becoming, an unfolding of potential, “form forming itself”. The mature organism, on the other hand, has more of an already achieved form (although the processes of self-maintenance — breaking down and building up — continue for a lifetime). The power by which the organism’s body was formed is itself partly transmuted (to take the case of animals) into an ability to employ the body instrumentally in the world, whether to graze or hunt or play or mate. But here, too, we are looking at significant patterns — forms of living activity.

Connecting all this to the companion posting entitled What absent genes don’t do, where I raise (parenthetically) the issue of holism: surely one of the ultimate goals of the biologist is to grasp the recognizable identity underlying (or hovering over) the ceaseless transformation that is any given organism — that is, to grasp the organism as a whole, as a living activity, in its own terms. This identity cannot be equated with any particular material configurations caught up in the identity, but (it is well to acknowledge the mysteries that abound in biology today) only with whatever shaping power coordinates and gives a coherent temporal form to those configurations over a lifetime. This is implied by current observations even if we are unable to observe anything (any thing) we might equate to that “shaping power” itself — a truth biologists have a hard time reckoning with.

One other note. When Lawrence talks about the form of the nose being recorded precisely and recorded somewhere, it sounds as though he is imagining something like the genetic code, traditionally conceived as a precise set of instructions embodied in the DNA sequence. But whether or not that is his thought, the term “precisely” is oddly out of tune with everything we know about the contingency, plasticity, and adaptability of developmental processes.

Nothing about development is explained precisely, and nothing is wholly determined by a single location. This is true (as one hopes he would acknowledge) regardless of whether making a change at a particular location would, under particular circumstances, have a dramatic effect — such as making the head fall off (see “The Complex Performance of the Three-Dimensional Chromosome”). That wouldn’t tell us much about how heads come to be as they are.

Tags: form/organismal; explanation/biological
Source: Vogel, Gretchen (2013). “Under Development”, Science vol. 340 (June 7), pp. 1161. doi:10.1126/science.340.6137.1161
Further information: In addition to the "Further information" links provided in the companion posting, “The Complex Performance of the Three-Dimensional Chromosome”, see my article, “Can the New Science of Evo-Devo Explain the Form of Organisms?”: http://natureinstitute.org/txt/st/mqual/form.htm. And on the shift from fluid and dynamic to a more rigid and fixed form, see "Free Life and Confining Form": http://natureinstitute/txt/st/mqual/genome_10_polar.htm

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Steve Talbott :: The Paradox in “Explaining” Form