. Walter M. Elsasser, The Physical Foundation of Biology (Elmsford, N.Y.: Pergamon Publishing Co., 1958).

. Eugene P. Wigner, “The Probability of the Existence of a Self‐reproducing Unit,” in The Logic of Personal Knowledge: Essays Presented to Michael Polanyi on His Seoentieth Birthday (London: Routledge Kegan Paul, 1961).

. Henry Saint‐John, Viscount Bolingbroke, Philosophical Works of the Late Right Honorable Henry St. John, Lord Bolingbroke (London: David Mallett, 1754).

. MichaelPolanyi, “Life Transcending Physics and Chemistry,” Chemical and Engineering News 45, no. 35 (1967):54–66; and “Life's Irreducible Structure,” Science  160 (1968): 130–212.

. Max Delbrück, “A Physicist Looks at Biology,“ Transactions of the Connecticut Academy of Arts and Sciences 38 (1949):173‐90; and in Phage and the Origins of Molecular Biology, ed. John Cairns, Gunther S. Stent, and James D. Watson (Cold Spring Harbor, N.Y.: Cold Spring Harbor Laboratory of Quantitative Biology, 1966).

. Erwin Schrödinger, What Is Life? (Cambridge: Cambridge University Press. 1944).

. For example, it is a familiar paradox in projective algebraic geometry that an argument like Wigner's can be used to prove that every conic section is a pair of straight lines.

. For example, if Wigner's reasoning here were applied to nuclear fission, it would persuade us that a chain reaction is impossible‐because we can never stipulate that the entry of a neutron into a specified nucleus will certainly release two neutrons.

. LeslieOrgel, “The Maintenance of the Accuracy of Protein Synthesis and Its Relevance to Ageing,” Proceedings of the National Academy of Science  49 (1963):517–21.

. See B. J.Harrison and RobinHolliday, “Senescence and the Fidelity of Protein Synthesis in Drosophila,” Nature 213 (1967):99–192; and RobinHolliday, “Errors in Protein Synthesis and Clonal Senescence in Fungi,” Nature  221 (1969): 1224–28.

. Leonard Hayflick, “Cell Culture and the Aging Phenomenon,” in. Topics in the Biology of Aging, ed. Peter L. Krohn (New York: Interscience Publications, 1966).

. John Desmond Bernal, “Molecular Structure, Biochemical Function, and Evolution,” in Theoretical and Mathematical Biology, ed. Talbot H. Waterman and Harold J. Morowitz (New York: Blaisdell Publishing Co., 1965).

. Ibid., pp. 96–97.

. William Paley, A View of the Evidences of Christianity (London: R. Faulder, 1794).

. Ronald A. Fisher, The Genetical Theory of Natural Selection (Oxford: Clarendon Press, 1930).

. See Hans A.Bethe, “Energy Production in Stars,” Physical Review  55 (1939): 434–56.

. See James D.Watson and FrancisH. C. Crick, “Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid,” Nature  171 (1953):737–38.

. For a fuller account, see my Condon lectures for 1967 at the University of Oregon, published under the title Nature and Knowledge (Eugene: University of Oregon Press, 1969). Recently David Bohm has put forward a similar scheme for an inherent hierarchy of complexity, in which he calls levels of order what I call strata of stability. See his “Some Remarks on the Notion of Order,” in Towards a Theoretical Biology, ed. C. H. Waddington (Chicago: Aldine Publishing Co., 1969), vol. 2.

. It should be remarked that Johann von Neumann's quantum theoretical proof of the Second Law (see his Mathematische Grundlagen der Quantenmechanik [Berlin: Springer‐Verlag, 1932]), like Wigner's argument above, assumes that the behavior of a system to which it is applied can be represented by a random symmetric Hamiltonian matrix–‐that is, contains no hidden inner relations.