The Triple Helix contains three chapters that originally were lectures delivered by Richard Lewontin to the Lezioni Italiani in Milan. In them, Lewontin, the Alexander Agassiz Research Professor at Harvard University’s Museum of Comparative Zoology, admonishes researchers in the life sciences for ignoring important ideas and so overspecializing that their results, especially those concerning genes and inheritance, are misleading. He proposes that a revolution in the biological sciences is needed to redirect modern research. Apparently because these lectures were heavily critical, his editor suggested adding a fourth with recommendations for improvement.
The central question that unites the four essays is a vexing one: Why are individual organisms, even those of the same species, both similar and different? The answer has more than scientific value; it has deep philosophical and social implications, because it concerns how people should think about nature and view themselves in relation to it. Lewontin’s approach to the answer departs from that of mainstream biology and the popular accounts derived from it that shape public opinion.
“Gene and Organism” opens with a warning about metaphors: They are useful in solving problems but lead scientists astray if taken too literally. A dominant metaphor in biological theory, says Lewontin, comes from René Descartes’s metaphor of nature as a machine—the clockwork universe. For example, it appears in modern life science in the description of deoxyribonucleic acid (DNA) as a “blueprint” or the genetic “program” that determines the development of every organism. The mechanistic metaphor carries the implication that DNA is self-sufficient in replicating itself and manufacturing proteins for metabolism. Lewontin adjudges this view of an organism’s relation to its genetic heritage as insufficient, producing bad biology. He sets forth examples of studies about plants, flies, and human intelligence both to show how the evidence casts much doubt on the DNA-as-software theory and to warn that, in the case of intelligence studies, it can have incorrect and invidious social implications.
Its environment is also a necessary part of an organism’s growth, Lewontin insists, and, specifically, the order of environmental influences that the organism passes through. However, a third influence is also apparent at the cellular level: random molecular interactions that result in biochemicals’ processing at differing rates among cells and in a variety of cell sizes. Genetic inheritance, the sequence of external environments, and random molecular events form a mutually influencing “ontogenetic process.” (Presumably, this is the “triple helix” of the book’s title. Lewontin does not use the phrase, which may be the publisher’s addition.) It is a stunning essay, combining clear, cogent references to Platonic and Cartesian philosophy, Darwinian natural selection theory, and microbiology to argue that modern biologists have indeed neglected environmental influences in order to concentrate on decoding genes. Moreover, Lewontin points out that promised medical benefits from linking human diseases to specific genes—benefits that may be exaggerated—attract the largest share of money for research. Even more important, to him at least, genetic studies fail to explain why individuals in the same species can vary so much in appearance and behavior. If DNA were really like a computer, he quips, it would be a very poor one that computed such a variety of answers to a problem from the same program.
Just as the first essay addresses misconceptions in the gene-organism relation, “Organism and Environment” considers how evolutionary biology became straitjacketed by its prevailing investigative methods. He considers the traditional conceptions of the ecological niche, fitness, and adaptive value, predicated on the view that species are passively adapted to an environment by internal and external evolutionary forces, to be outdated. He criticizes the trend in which researchers identify a specific trait in an organism and then hunt in its environment for an external, physical cause for it, the cause being some feature of the eco-niche that requires the trait for survival. The view that the environment is a priori and causally independent of the organism is, he says, clearly wrong. He calls for a new understanding of the organism-environment relation.
He recommends that instead of the “metaphor of adaptation” biologists model...
(The entire section is 1841 words.)