In illustrating this humble article by a fragment of the hallucinating triptych by Hieronymus Bosch, I've let myself be carried away by a series of associations. At the outset, all I really needed was a simple Necker Cube:
This is a familiar graphical device that demonstrates how an image can be interpreted in two different ways. The horizontal line at the bottom can be envisaged as either the front edge of a cube, or alternatively the rear edge.
Since a Necker cube is a rather austere object, I thought it might be preferable to call upon one of the numerous fantastic graphical constructions of M C Escher [1898-1972], some of which might be described tersely (too tersely, of course, since the artist was a genius) as enhanced Necker Cubes.
Then I said to myself: Well, if I'm looking for a disconcerting graphical vision of things, why not get back to Hieronymus Bosch, who demonstrated so strikingly that the ordinary world is extraordinary?
In fact, I merely wanted to preface an account of my recent rereading of the masterpiece by Richard Dawkins: The Extended Phenotype. The underlying theme of this brilliant text is that the author would like to persuade his readers to choose between two plausible, if not equivalent, ways of looking at the world of Darwinian evolution. On the one hand, there's the classical notion that an organism such as a bird in the Amazonian jungle, for example, will emerge as an evolutionary winner if its fitness for survival is maximized with respect to that of other birds. On the other hand, there is Dawkins' celebrated "gene's-eye view" of the situation, presented in his earlier book The Selfish Gene, according to which all evolutionary battles take place primarily at the level of genes, which only emerge as victorious survivors if they are capable of replicating (reproducing themselves) more plentifully than their rivals.
Normally, we think of the phenotype of a gene as the macroscopic effect it has upon the organism in which it resides. For example, when a gene is responsible for giving a child red hair, this particular outcome designates a phenotype of that gene. In the Dawkins title, the adjective "extended" highlights an amazing aspect of certain selfish genes. In a nutshell, the effects of a gene can sometimes extend well beyond the bodily limits of the host organism (human, animal or plant) in which it resides. A spectacular example of this effect is provided by beavers that build dams that increase their chances of survival. It would be absurd to imagine a stressed beaver gene mumbling to itself: "I must get around to building a dam, otherwise I won't survive." But the presence of the gene has the same final effect as if it were consciously aware of the need to build dams.
In using the metaphor of a Necker Cube, Dawkins is telling us that we're free to switch back and forth between two complementary images:
— On the one hand, there's the image of beavers surviving because their inherent fitness includes the ability to build dams.
— On the other hand, you have the relatively abstract image of a gene whose presence in a beaver causes the animal to build dams, whereby ensuring the survival of the gene in question... not to mention the survival of the beaver that hosts that gene.
The raison d'être of The Extended Phenotype consist of trying to persuade us that the second attitude is preferable. But you have to read the arguments minutely, through to the final pages, to be fully impregnated with the power of Dawkins' fascinating message.