Locke on Mixed Modes, Knowledge, and Substances

Notes and Discussions LOCKE ON MIXED MODES, KNOWLEDGE, AND SUBSTANCES In a recent discussion of Locke's views on mixed modes and knowledge David L. Perry points out that ideas of mixed modes (and of relations) do not have "an entirely empirical source in Locke's account." x Ideas of mixed modes are complex ideas and although the simple ideas which are the constituents of ideas of mixed modes have an empirical origin, the unity which forms these simples into complexes is "always the product of a mental activity." 2 He also points out that, according to Locke, ideas of mixed modes are themselves archetypes not intended to conform to an external reality and that they are adequate ideas. Perry claims at the beginning of his paper that these features are the basis for Locke's attempt to account for the possibility of at least a portion of that klnd of knowledge which has come to be known since Kant as "synthetic a priori," namely, knowledge of necessary yet instructive propositions. Yet, at the end of his paper, Perry states (correctly we think) that these features of ideas of mixed modes do not account for the possibility of this kind of knowledge. Perry says that it is an unexamined conviction of Locke that we can apprehend necessary, instructive agreements and disagreements between ideas: "Locke evidently recognized no problem in this regard; at least he proposed no solution." 3 It seems reasonable to suggest therefore that Locke never intended these features of ideas of mixed modes to provide an account of the possibility of this kind of knowledge at all. It is our contention that the features of ideas of mixed modes (and of relations ) 4 mentioned above are the basis for Locke's attempt to account for the difference in ontological status between mixed modes (e.g., lies, murders) on the one hand and substances (e.g., trees, chairs) on the other. 5 This difference in turn plays a role in Locke's doctrine of sensitive knowledge, that is, in our knowledge of the "existence of finite beings without us." e Perry finds a contraDavid L. Perry, "Locke on Mixed Modes, Relations and Knowledge," Journal of the History of Philosophy, V (1967), 219-235. The quotation is from 219. s Ibid., 221. 8 Ibid., 235. 9 In what follows we shall ignore ideas of relations. Perry points out the differences between these and ideas of mixed modes. s We consistently distinguish ideas of mixed modes (and of substances), which are mental entities, from mixed modes (and substances) themselves, which are extramental things. Perry rightly admonishes Locke for "... the careless manner in which he vacillates between writing of mixed modes as complex ideas and writing of them not as ideas, but as objects of which we have ideas" (220). We shall follow Perry in adopting the practice of treating mixed modes and substances in the latter way. a John Locke, An Essay Concerning Human Understanding, ed. A. C. Fraser (New York: Dover Publications, Inc., 1959), Bk. IV, Chap. ii, Sect. 14. Subsequent references to Locke's Essay will be cited by book, chapter and section, e.g., IV, ii, 14. [193] 194 HISTORY OF PHILOSOPHY diction in Locke's view of the ontological status of mixed modes. He says: "There is simply a contradiction between Locke's denial of the exlernal reality of mixed modes and his admission that some mixed modes have real existence." 7 While about Locke's doctrine of sensitive knowledge he says: And in the case of knowledge of external things immediately present to one's senses, Locke relies (as he must) entirely upon the psychological criterion of indubitability without appealing to necessary agreements between ideas.... [W]here beliefs concern substantial existence and cmnnot be based on merely conceptual relationships, Locke takes inability to doubt as sufficient condition for knowledge,s In this note we shall describe what Locke believes the difference is in ontological status between mixed modes and substances, and we shall utilize this difference in showing that, properly understood, there is ~o such contradiction in Locke's doctrine of mixed modes as Perry contends and also that in the ease of sensitive knowledge Locke...