A concept of extended phenotype might be even more important Richard Dawkins contribution to homonism than that one of selfish gene. What makes both of them so important is that they help us understand identity better. Even more: it is entirely impossible to start to dwell into identity abyss without the help of selfish gene and extended phenotype.
The first surprise comes already with the first milestone. They do not narrow the path towards identity but widen it. We all take identity as something so self evident that we do not even consider it seriously. I have an identity as much as a company, a cat or a table has it. We normally take identity as a unity of cells, particles or any other type of elements that when assembled in particular arrangements, they act as all constituting one identity. My blood cell does not constitute my identity when it is outside of my body. A CEO of an company can be a part of a family (one identity) in one moment and a part of his company (another identity). A wood cell in a table used to be part of another identity before a tree was cut. Normally we easily draw borders between different identities even though parts of that identity “travel” from one identity to another.
Dawkins shattered such easy going identity formation by his famous beaver story. Shortest possible version would be that as much as beaver tail and teeth (part of its phenotype) are parts that evolved over time to sustain beaver existence, dams that are created by beavers constitute beaver extended phenotype that has same evolutionary role as tails or teeth. To say metaphorically: as much as beaver grows teethe it grows dams. Are then dams a part of beaver identity as much as teeth even though they are not part of its body strictly speaking?
Farewell to essentialism
For most of the part essentialism is wrong. This blog as such could be understood as an argument against essentialism. Not only that essentialism fails when explaining physical reality (people, companies, objects…) as we have seen above, but it fails as well in memetic realm. As explained for instance in Brandlife but as well in this post, there is no hope in search for essence in any meme-complex and even not in meme itself. But one should not mistake essence for identity though! For the reason that there is no essence, the objectivity of identity is interrelational. That identity changes very much does not mean that it does not objectively exist (contrary to essence that exists only as imagination).
A smartphone story
But let us go back to extended phenotype on more intuitive/basic level with the help of smartphone. A smartphone is a tool that evolved recently as human extended phenotype. It helps people to communicate faster, to get information about environment faster and to control environment faster as much as brans do for instance. That means that smartphones have all necessary features of evolved tool that help us survive as much as our brains, legs or livers. Since smartphones are not yet part of our bodies (cyborgs are still very rare!) they should be understood as our extended phenotypes.
After we adapt to a notion that my mobile phone is part of extended phenotype of my body, we we come very close to understand that borders between “living identities” and “inert objects of nature” are simply speaking blurred. If smartphone is not only part of my extended phenotype but with that a part of my identity, that my identity as living creature does not exists as something that performs metabolism or autocatalytic work. (Autocatalysis as essential chemical reaction of metabolism and with that something that nicely defines life.) Smartphones have no metabolic function (so far) but are as such part of our identities. Smartphones emerged as an extension of certain brain and body functions, physically separated from brains in “my phenotype”, but at the same time as an extension on the same level. My phone is thus perfectly comparable with my hand, that is at the same time separated and linked to my brains. As a matter of fact brains are extensions of my hands and vice versa. Consequently not only that smartphones are extended phenotypes of my brains, but also brains are extended phenotypes of smartphones!
Life becomes something that has no phenotypic domain. Life is fully decentralized and fully de-essentialized.
But extended phenotype became even more important after somatic mosaicism was discovered recently. Somatic mosaicism occurs when the somatic cells of the body are of more than one genotype. Not going deeper into extremely interesting discoveries about heredity linked to somatic mosaicism there is one important message building up: our cells do not have homogeneous chromosome history. Different cells even within one organ come from different genotypes. It was even confirmed that genotypes are transferred from children to their mothers where they then persist as somatic cells for years and even for decades. Somatic identities are thus not only passed down the lineage but passed up as well!
We should thus conclude that identity is objective but arbitrary like language. It is created a posteriori and never a priori. It also highly heterogenous. It merges entities from all known domains, living, physic and memetic in one identity that combines phenotypes and extended phenotypes at will. Wether different genotypes within one body reflect themselves in phenotypes or extended phenotypes makes no difference. Wether something is phenotype or extended phenotype is arbitrary decision dependant on specific interests, viewpoints or circumstances. It is objective but not fixed. It is objective but at the same time inter-subjective and even inter-objective.