Evolutionary.

Biology and the foundation of ethics Author not listed 1999 Concepts of Species Author not listed Year not listed Evolution and Ethics Huxley, Thomas H 1896 Evolutionary ethics Flew, A.G.N 1970 Evolutionary ethics Flew, A. G. N. 1967 Justice Spencer, Herbert 1891 Modeling rationality, morality, and evolution edited by Peter A. Danielson 1998 Morals in evolution Hobhouse, L. T. 1915 The ethics of belief and other essays Clifford, William Kingdon 1999 The goodness of gods Westermarck, Edward 1926