Institute of Philosophy
Biological Identity Conference
Evolutionary individuals and their offspring
I present a concept of the biological individual that is used within evolutionary biology. I explicate the concept through a discussion of the theoretical roles that it is expected to play, and detail the constraints that these roles imply for the concept. The concept emerges from what can be described as a levels-of-selection approach to evolutionary individuality, since the entity is picked out primarily in terms of its capacity to undergo evolution by natural selection at one level rather than another. I’ll use two case studies to show the concept at work.
First, in the evolution of multicellularity in bacteria, second, in discussions about the role of sex in clonal plants. Finally, I will discuss the relevance and implications of this evolutionary concept for issues about biological identity. We can categorise three classes of biological identity relation. In the first class, an organism at time t is identical with an organism at time t+1. In another class, an organism at time t is completely different from an organism at time t+1 and counts as a separate individual. In between these cases is a third, in which an organism at time t is similar to, but still different from an organism at time t+2 such that the latter is an offspring of the former. I try to explicate the relevant senses of ‘similar’ and ‘different’ for marking these distinctions. But perhaps the most interesting point, in respect of interests about biological identity in general, is the finding that the boundaries between these three cases may not be sharp. The relationship between self and other, at least in the case in which parents are related to their offspring – can be gradient.
Recent debates in metaphysics on personal identity and material constitution have seen a rise of theories which appeal to a biological understanding of identity. So-called animalists claim that the puzzles of standard psychological theories of personal identity can be avoided by the insight that we are essentially animals or organisms rather than persons and that the necessary and sufficient conditions of our identity over time therefore are purely biological in character. Moreover, it has been argued (most famously by Peter van Inwagen) that if there are any composite objects at all in the world, then these are those studied by biology. According to this view, there are no inanimate things like stones or cars, strictly speaking, as these turn out to be just collections of particles; but there are living organisms, due to a special unity making them each one rather than many.
It is time to investigate whether, and if so how, the concept of biological identity can indeed serve the functions metaphysicians attribute to it. For that purpose, the conference will aim to confront the metaphysical motives for proposing biological conceptions of identity, diachronic as well as synchronic, with the scientifically informed research on biological identity which has been carried out within the philosophy of biology but which so far has been little noticed by the metaphysics community. The conference seeks to connect these two hitherto largely separate debates so as to put future metaphysical allusions to biological identity on more solid grounds and, at the same time, to raise awareness for the metaphysical implications of the empirically founded models of biological identity developed in philosophy of biology.