Abstract

In this work it is proposed that the conditions of identity for biological organisms are given by the following principle: for all organisms x and y, x = y if and only if x has been caused by the self-preserving activity of y. This principle determines both the inter-temporal identity of organisms and the identity of organism in different possible worlds. It unifies what can be supposed about conditions of identity coming from —at least— three different conceptions about the nature of biological organisms, those of RobertWilson, Thomas Pradeu and Ellen Clarke. These conceptions are presented and compared.