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Coincidence in Evolution in "Chance and Necessity"

Rachel Tashjian's picture

I think the element of Biology 103 that I enjoyed most was its ability to answer all my ‘big questions.’ Before the course, I did not understand molecular evolution, the purpose of the scientific method, or how chemistry was connected to biology, and I left feeling pretty confident in my comprehension of these things. Because science is a loopy storytelling process, though, I was continually reassessing my ideas of what these processes meant, in particular, evolution. While our society’s great debate on evolution often hinges on the idea that evolution denies the ‘miraculous’ associated with a divine being (like that of creationism or intelligent design), the play between genes and environment and particularly  improbable assembly certainly seemed miraculous to me.

Reading the book Chance and Necessity by Jacques Monod often helped reaffirm some of the things we discovered in class, and when I reached the section on evolution, I hoped that it would continue to do so. But Monod’s theories on evolution challenged me more than they seemed to agree with me, and I wondered if it was unmasking a sheen I had put on evolution during the process of discovery. Are Monod’s theories on evolution really the same as Bio 103’s? And if so, is evolution just ‘mere’ coincidence?

In class, we recognized that there is no nature-nurture controversy because both genes and environment affect a person’s existence. On a larger scale, one might say that this means an evolutionary trend is directed by both the genetics of a species—for example, Darwin’s finches (as well as most mammals) all have a nearly identical genetic makeup) and by the environment they inhabit (but the finches differ due to differing environmental factors). Monod seems to suggest something similar: “the initial choice of a certain kind of behavior (for example, in the face of attack from a predator) commits the species irrevocably in the direction of a continuous perfecting of the structures and performances this behavior needs for support (p. 127).” While this does not deny the influence of both genes and environment, it seems to isolate the two: genes cause one to make a decision (like continually running from a predator), while the environment shapes the outcome of that decision (if a species moves to a new location to avoid the predator, the new location will create new standards of survival and behavior). But Monod’s idea could be faulty here because of the phrasing of this idea (and the book is a translation from French); genes are still a factor in the species changing to adapt to their new environment, and the environment is a factor in making a choice to move permanently away from a predator or stay. So although Monod’s phrasing does not present the whole of the nature-nurture interplay (and his presentation is not as well articulated), the implication is there.  

(I do dislike Monod’s use of the word “perfection,” however, as it insinuates that evolution is a process of moving towards better species, which we all agreed is not a ‘goal’ of evolution. However, because the book was written in 1971, it is likely that he was not acquainted—nor was much of the scientific world—with this idea.)

More troubling to me than Monod’s seemingly segregated ideas of genes and environment was his explanation of the role of what we called ‘improbable assembly.’ Monod moves towards this theory by asking the question to which I have been searching for an answer: did the molecular situation that yielded life occur because there were “stereochemical affinities” between molecules? Or is “the code’s structure chemically arbitrary?” (p. 143)  Like me, Monod concedes that “the first of these...seems by far the more appealing;” this suggests that he, too, is uncomfortable with life as ‘mere’ coincidence. “Life appeared on earth: what, before the event, were the chances that this would occur?” Monod then asks, and affirms, as we did in class, the “probability was virtually zero.” (p. 144).

I really enjoyed this passage, as I had thought throughout the course that improbable assembly was not by nature tied to coincidence. Improbable assembly seemed to me a similar to but better story than ‘we are special,’ because it accommodates the difference between living things and probable things (dust, rocks, etc.), and the implications of “improbable” seemed similar (though more intellectually sound) to ‘special.’
But Monod follows his theory of improbable assembly with something unfortunately undeniable: the first hypothesis—that life occurred from molecules with “affinities” to one another and is therefore not just coincidence—has never been proven, despite numerous attempts (p. 144). He acknowledges that most scientists “recoil at this idea. It runs counter to our very human tendency to believe that behind everything real in the world stands a necessity rooted in the very beginning of things. Against this notion, this powerful feeling of destiny, we must be constantly on guard” (p. 145). While at first I was highly uncomfortable with this statement, I realized that because I agree with his observations—the “affinity” theory has never been proven, and random variation plays a major part in evolution and therefore probably in the molecular structures that create the circumstances for life—this is a really good story. By making me uncomfortable, and asking me to “revolve” my story about evolution, Monod untied my final string to scientific-method/ask-a-question-and-make-the-observations-answer-it biology. While this brand of science may not be as immediately miraculous, the realm of storytelling, of “absolute creation and not revelation,” is far more creative (p. 115).

Monod, Jacques. Chance and Necessity. New York: Alfred A. Knopf, Inc. 1971.


Paul Grobstein's picture

Creation and revelation, chance and necessity

Some seriously interesting wrestling here, around the question of whether evolution, and science as well, are to be thought of as "revelation" or "creation". Yes, we all have a "tendency to believe that behind everything real in the world stands a necessity rooted in the very beginning of things", and so have an inclination to look for that which makes things we want to account for "necessary." Monod's point (and, subsequently, Stephen J. Gould's) is that such things may not exist, that some measure of genuine indeterminacy may be a necessary component of any explation of biological phenomena. That's not to say that "affinities" between molecules are not "real", nor that they may not contribute to what happens (as does the "choice" an idividual organism makes), but it is to say that they may not determine what happens (bacuse of, among other things, "chance"). And the point is of course significant beyond biology, indeed beyond science. If we don't think of the world (and ourselves) in terms of simple cause-effect relationships, then what happens becomes indeed at least a s much"creation" as "revelation". And we need a different approach to both inquiry (see From Complexity to Emergence and Beyond: Towards Empirical Non-Foundationalism as a Guide to Inquiry) and life?