Hume’s Considered View on Causality

Hume presents two definitions of cause in his Enquiry which correspond to his two definitions in his Treatise. The first of the definitions is ontological and the second is psychological; indeed, the definitions are extensionally and intensionally distinct. The critical mistake of the skeptical interpretation is the assumption that the two definitions are equivalent, and the critical mistake of the necessitarian is the assumption an association of ideas can be had from one experiment. This paper attempts to clarify Hume’s finally considered position of causality. 1 The Problem of Interpretation Before attending to the influential elements of Hume’s theory, it is worthwhile to indicate several reasons for the often disparate interpretations of causation drawn from A Treatise of Human Nature (1739),1 An Abstract of a Treatise of Human Nature(1740), and An Enquiry Concerning the Human Understanding (1758)2 The purpose of this section is to indicate that much of the psychological support for the causal argumentation in the Treatise is irrelevant to the influence of Hume’s doctrines; in this manner, Hume’s theory of causality can be extricated to some extent from his detailed psychological arguments without creating major misunderstandings. Hume completely disavowed the Treatise and wrote in an advertisement to the Enquiry that the argument in the Treatise needed clarification and better expression. He admits to “some negligences” in reasoning, and he requests that the work 1E. L. A. Selby-Bigge (1888; rpt. London: Oxford Univ. Press, 1968). Hereafter page references to A Treatise of Human Nature will be cited in the text as “T.” In quotations from this work spelling but not punctuation has been modernized. 2E. P. H. Nidditch, 3rd ed. (1777; rpt. London: Oxford Univ. Press, 1975). Hereafter page references to A Enquiry Concerning the Human Understanding will be cited in the text as “E.” In quotations from this work spelling but not punctuation has been modernized. 1 THE PROBLEM OF INTERPRETATION not be regarded further. In addition, the Abstract, published anonymously, is far too sketchy by itself to provide a focus for causal doctrines. It is, for the most part, a summary of the arguments given in the Treatise and was disowned also.3 Thus, if we were to take Hume at his word, only the Enquiry should be studied for his full causal doctrines; however, this is not usually done for the following reasons. Hume’s youthful enthusiasm and to some degree his perspicacity in the Treatise are attenuated in two significant ways in the Enquiry. First, causal doctrines are reformulated with an eye toward simplicity and clarity; second, some difficult and controversial subjects of the Treatise are dropped from the Enquiry. Naturally, this situation opens fertile territory for scholars. For example, are there insurmountable differences between the works?4 More specifically, is Hume’s retraction in the Enquiry to be taken seriously?5, p. 57, argues that Hume simply wanted to dissociate himself from a badly received work. Some writers have taken Hume at his word and only considered the Enquiry; see, for example, Anthony Flew, Hume’s Philosophy of Belief New York: Humanities Press, 1961), pp. 1-17. Are the accounts of causation in both works consistent with one another?6 Is there a predominant doctrine of causality in the two works?7 There have been several different plausible responses to these questions, and because of this, Hume’s influence is manifold. More important for the present discussion, several critical problems arise from the omission of vital topics in the Enquiry–topics necessary for the completion of the causal argument. The ideas of existence, external existence, and substance, as well as the distinction between causation as a philosophical and a natural relation are omitted. Furthermore, the consideration of space and time is almost totally 3Charles Hendel, however, argues that the Abstract was an outline of the Enquiry rather than the Treatise. See his “Editor’s Introduction,” An Inquiry Concerning Human Understanding (Indianapolis: Bobbs-Merrill, 1955), pp. xviii-li. J.O. Nelson suggests that the Abstract might have been written by Adam Smith. See his “Has the Authorship of the Abstract Really been Decided?,” Philosophical Quarterly, 26 (January, 1976), pp. 82-91. 4L. A. Selby-Bigge argues in the “Editor’s Introduction” to the Enquiry by means of a passage by passage comparison that the differences in the two works are significant, but there is not a substantial doctrinal difference. A survey of differences of opinion on this view point is illustrated by the following articles: W. B. Elkin, “Relation of the Treatise of Human Nature (Book I) to the Inquiry Concerning Human Understanding,” Philosophical Review, 3 (1894), pp. 672-688; J. O. Nelson, “Two Main Questions Concerning Hume’s Treatise and Enquiry,” Philosophical Review, 81 (1972), pp. 333-352; N. Kemp Smith, “David Hume: 1739-1939,” Aristotelian Society Proceedings, Suppl. Vol. 63 (1939), pp. i-xxiv. 5L. F. V. Kruse in Hume’s Philosophy in his Principal Work the Treatise, and in His Essays, trans. P. T. Federspiel (Oxford: Oxford Univ. Press, 1939 6J. O. Nelson in “Two Main Questions” convincingly argues that Hume disowned the Treatise because of its metaphysical arguments–an interpretation which this essay later adopts. 7In this chapter I assume without attempting to prove that the causal arguments in the Treatise and Enquiry are compatible; consequently, since both works have been influential, both are utilized in constructing Hume’s doctrines. For reasons given later, the causal arguments in the Enquiry are given more weight than is usually accorded by contemporary commentators.