A revised entry on the genotype-phenotype distinction has been published by the Stanford Encyclopedia of Philosophy. A major difficulty we had preparing this revision followed once it was noted that philosophers write on the genotype-phenotype relationship, not on the genotype-phenotype distinction. In doing so, they take the predominant current meaning of the genotype-phenotype distinction, namely DNA versus traits, as not needing to be problematized. Indeed, the authors and articles we were asked to bring into the revision were not focused on the distinction, but on the relationship.
One friendly philosopher reader suggested that we preserve the review format for an SEP entry by paying attention to philosophical debates about, say, distinctions, of which the genotype-phenotype distinction would be one example, and about the environment, given that this is surely needed in moving from a genotype to a phenotype, and so on.
We chose instead an alternative way to help frame and orient readers’ inquiries, which we take to be the deeper purpose of having encyclopedia entries out there in the world. We relate Johannsen’s foundational paper to practices or assumptions regarding control of biological materials and conditions. Subsequent developments are then described in relation to problems introduced by conceptualizing heredity on the basis of breeding experiments. The detail in an early section on Johannsen’s paper and in the following section, which takes readers from Mendelian experiments to present-day molecular biology, is important not as a matter of doing history, but to build distance from the predominant current-day meanings and establish a space in which modern users of his terms can consider issues that had been left behind.
What follow are some schemas–comments welcome–that convey the theory of heredity that is meant to apply to life, including naturally variable situations, and the experimentally controlled situations in which its elements are demonstrated. The implication, explored in the SEP entry, is that there is room to “develop methods to bring back and tie together what had been de-emphasized through the control of biological material and conditions employed in the experiments.”