^{page 48 note 1} von Neumann, J., in Cerebral Mechanisms in Behavior, ed. Jeffress, Lloyd A. (New York, 1951) p. 34 et passim.Google Scholar

^{page 49 note 1} Throughout this paper, ‘unconditional assent’ is used as shorthand for ‘assent to which one is logically committed, whether one likes it or not, by accepting the theoretical assumptions and data on which the claim is based’. In this sense celestial mechanics, for example, specifies definitive answers to questions about the dates of future eclipses, which can claim the unconditional assent of anyone who accepts the premisses. There is of course no suggestion that these premisses themselves can claim unconditional assent.

^{page 50 note 1} MacKay, D. M., ‘Brain and Will’, The Listener, 9 and 16 05 1957Google Scholar, also (revised) Faith and Thought, xc (1958) 103–15Google Scholar; idem, ‘On the Logical Indeterminacy of a Free Choice’, Mind, LXIX (1960) 31–40Google Scholar; idem, ‘Information and Prediction in Human Sciences’, in Information and Prediction in Science, ed. Dockx, S. and Bernays, P., Symposium of Int. Acad. for Phil, of Science, 1962 (New York, 1965) pp. 255–69Google Scholar; idem, Freedom of Action in a Mechanistic Universe, Eddington Lecture (Cambridge, 1967).Google Scholar

^{page 52 note 1} This is what I have meant elsewhere (‘On the Logical Indeterminacy of a Free Choice’, loc. cit.) by saying that such self-nullifying conditionals have a different truth-value for the agent and for the onlookers.

^{page 53 note 1} Franklin, R. L., Freewill and Determinism (London, 1968) p. 134.Google Scholar

^{page 53 note 2} There must, after all, be a vast number of other counter-conditions that might equally well have been specified!

^{page 53 note 3} See ‘On the Logical Indeterminacy of a Free Choice’, loc. cit., p. 37Google Scholar, and ‘Information and Prediction in Human Sciences’, loc. cit., pp. 265–8.Google Scholar

^{page 53 note 4} MacKay, D. M., ‘On the Logical Indeterminacy of a Free Choice’, loc. cit. pp. 31–4Google Scholar, and Freedom of Action in a Mechanistic Universe.

^{page 54 note 1} This is not to be confused with the distinction, to which Sir Arthur Eddington (‘Indeterminacy and Indeterminism’, Proc. Aristot. Soc. Suppt., x (1931) 161–82, esp. 175Google Scholar) and Lord Halsbury (‘speculative Truth’, Philosophy, xxxii (1957) 289–301Google Scholar) among others have drawn attention, between explicability-in-retrospect and predictability. The scientific ‘determinism’ that we are considering would imply that human actions should be both explicable-in-retrospect and predictable in principle for non-participant observers. My point is that, even so, these actions need not, and in significant cases would not, be determinate in the metaphysical sense given.

^{page 55 note 1} See ‘Information and Prediction in Human Sciences’, loc. cit., p. 261.Google Scholar

^{page 55 note 2} Vesey, G. N. A., ‘Agent and Spectator’, in The Human Agent, ed. Vesey, G. N. A. (London, 1968) pp. 139–59.CrossRefGoogle Scholar

^{page 56 note 1} MacKay, D. M., (a) ‘Complementarity II’, Aristotelian Soc. Suppt., xxxii (1958) 105–22Google Scholar; (b) ‘A Mind's Eye View of the Brain’, in Cybernetics of the Nervous System, ed. Wiener, Norbert and Schade, J. P., Progress in Brain Research, 17 (Amsterdam, 1965) pp. 321–32; (c) ‘Complementarity in Scientific and Theological Thinking’, in J. Hick (ed.), Science/Religion: The Complementarity Hypothesis (in press).Google Scholar

^{page 56 note 2} Vesey, , loc. cit., p. 154.Google Scholar

^{page 56 note 3} MacKay, D. M., ‘Mindlike Behaviour in Artefacts’, Brit. J. Phil, of Sci., ii (1951) 105–21, esp. 118CrossRefGoogle Scholar. On this my view is very similar to that expressed by Professor R. J. Hirst in his lecture two years ago on ‘Mind and Brain’ (R.I.P. Lectures, vol. i: The Human Agent, ed. Vesey, G. N. A. (London, 1968) pp. 160–80)CrossRefGoogle Scholar. I do not, however, accept his argument on p. 178 that ‘an eventual theory of brain processes must be non-deterministic’ in order to make room for freedom of choice.

^{page 56 note 4} MacKay, D. M. (ed.), Christianity in a Mechanistic Universe (London, 1965) chap. 3.Google Scholar

^{page 59 note 1} MacKay, , Freedom of Action in a Mechanistic Universe.Google Scholar

^{page 60 note 1} See ‘Information and Prediction in Human Sciences’, loc. cit., p. 261.Google Scholar

^{page 62 note 1} For a recent survey of arguments that even the Laplacean model must suffer from a kind of ‘indeterminism’, see Hoering, W., ‘Indeterminism in Classical Physics’, Brit.J. Phil. Sci., xx (1969) 247–55.CrossRefGoogle Scholar