The relationship between biological genotypes and phenotypes forms the central subject matter of population genetics and evolutionary biology. Every organism, including us, may be viewed from either perspective - a duality that may pose a challenge to an integrated self-identity. For us this duality is even more problematic because our lives take place within a cognitive and cultural as well as the biological arena. And each of these arenas may be understood in terms of a generalized genotype including mental, cultural, and genetic models, as well as a generalized phenotype including behaviours, cultural practices and biological phenotypes.
Phenotypes engage in what Darwin termed a struggle for existence and their success in this struggle provides evidence that updates their species’ genomic model. In part, the phenotype is an experiment whose purpose is to provide evidence for the evolutionary process, evidence that increases the species' knowledge in its struggle for existence.
Some might consider that this inferential view of life reduces the role of phenotypes to that of disposable or mortal experimental probes, that our purpose as a phenotype is merely the testing and selection of genetic knowledge. This view suggests that the purpose of life is to evolve a nearly timeless and immortal repository of knowledge concerning increasingly powerful strategies for life’s existence and phenotypes exist merely to provide experimental evidence as grist for this mill of evolving knowledge.
It may be difficult for us to accept a diminished role for phenotypes. After all, for centuries before the existence of genetics was even known, the phenotype was biology’s sole focus of study. More personally, we identify with the phenotypic aspect of our lives. We experience ourselves and our short mortal lives as phenotypes as we strut and fret our hour upon the stage. We are actors following genetic scripts, and those scripts almost completely define us. A timeless and endlessly creative bard wrote those scripts, and surely the bard’s role is more admirable than is the actor’s.
It is difficult to accept that all our strutting and fretting may be mainly in vain, that any lasting influence or meaning is unlikely. This bleak view offers us little consolation in our brief, perhaps even disposable, phenotypic roles. We might gain some solace if we shift our focus from our mortal phenotypes to the more nearly immortal aspects of ourselves, our generalized genotypes in the form of our genomes, learned cognitive models and cultural knowledge.
While it is true that those aspects of our generalized genotypes marking us as unique individuals are nearly as mortal as our phenotypes, some may prove meaningful for the future. Regardless of our contribution, it is our generalized genotypes that directly connect us to a more nearly immortal chain of being. In this context, we assume a cosmic identity within an eternally evolving nature, or as Spinoza and Einstein saw it, a perpetually evolving God.
On the other hand, the purpose of our timeless genetic knowledge is to achieve existence, and existence is the realm of the phenotype. In this view, the purpose of life is to discover phenotypes that can exist. For ourselves, our life as a generalized phenotype motivates us to take part in the cutting edge of evolution and to create novel forms that may have a continued existence. These activities may include having children and participating in the cultural and social issues of our time.
The present is our time, as phenotypic players, to strut our stuff on the stage of existence. It is our turn to bring to life, one more time, that dead, musty knowledge stored in timeless genotypes. We are the growing green shoots of evolution; we revive that dead knowledge and give it a dynamic new interpretation. We play our role in a reinvigorated drama of exploration into the unformed and unknown future, maybe even leaving behind some novel ad-libs for the inspiration of future players.