, 2001, 'Appreciating the phenomenon of life', Graduate Faculty Philosophy Journal 23 (1), 51-69.
, 1984, Darwinism and ethics, in A. Caplan & B. Jennings (eds.), Darwin, Marx and Freud, Dordrecht, Springer, pp. 47-69.
, 1978a, Teleology and Darwin's the origin of species: beyond chance and necessity?, in S. Spicker (ed.), Organism, medicine, and metaphysics, Dordrecht, Springer, pp. 97-120.