Toward a Biology Worthy of Life > From Physical Causes to Organisms of Meaning > Brief excerpt
A project by Stephen L. Talbott

No “mechanism” controls the body’s rhythms

Biologists, of course, set out to identify the “clock mechanism” that was presumed to “control” [circadian] rhythms, and, yes, they found a rhythmical feedback loop involving genes and transcription factors in a certain area of the brain that seemed the perfect candidate. However, ongoing research has revealed distinct “clocks” in different mammalian organs and tissues, and indeed in every cell. These “clocks” are interwoven with each other and, it now seems, with virtually all aspects of the organism’s physiology — metabolism, reproduction, cell growth and differentiation, immune responses, central nervous system functions....

In each of these areas the quest for causes and master controllers leads to the usual perplexity about who’s doing what to whom. For example: “Although metabolism is thought to be primarily downstream of the cellular clock, numerous studies provide evidence that metabolic cycles can operate independently from or even influence circadian rhythms” (Kumar and Takahashi 2010). At the molecular level, one research team remarks that the enzymatic function of a certain clock protein “may be controlled by changing cell energy levels, or conversely, could regulate them” (Doi et al. 2006). In general, “It seems that connections between the circadian clock and most (if not all) physiological processes are bidirectional” (Yang 2010).

What we’re gaining from all this research is a wonderful portrait of the organism as a rhythmical being. Investigators have not found controlling mechanisms that single-handedly establish or govern the circadian rhythms of the organism, but rather are discovering how those rhythms come to expression at every level and in every precinct of the organism — perhaps more centrally here and more peripherally there, but altogether in a single, organism-wide harmony. There is no sensible way, as a scientist, to speak of particular mechanisms that explain this harmony. Instead, every isolated “mechanism” is found to be a reflection of the harmony, and we thereby gain further, detailed understanding of how the whole organism functions as a being in time.

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