 Finally, immunology contributes to a general account of selection (Darden and Cain 1989; Hull, Langman, and Glenn 2001). The clonal selection theory (CST), the foundational framework of modern immunology, states that the immune system relies on a Darwinian-like process of selection to permit differential expansion of lymphocytes, whose receptors are fitted to bind an antigen (Burnet 1959). Analogies between CST, natural selection theory, and selective theories in neuroscience have been generally regarded as examples of “a selection type theory” (Darden and Cain 1989). CST has also been compared to other selective theories to elaborate a general vision of selection as cycles of replication, variation and environmental interaction (Hull, Langman, and Glenn 2001). Such a general account of selection would not only elucidate the most fundamental principles of evolution, but would also serve as a guide for future selective theories, e.g., neural group selection (cf. Edelman 1974, 1987). Differences between selection theories have also been recognized and suggest that unlike evolution of species, selection in somatic systems (in particular the neural system) does not fully account for the adaptation of the developing populations (Dumouchel 1996). More generally, Piattelli-Palmarini suggested that such a general scheme could be of use in cognitive science and linguistics, as well as in other disciplinary domains outside of biology (Piattelli-Palmarini 1986).