Response to My Critics

I am extremely grateful to all my commentators for their very careful engagement with my book.¹ Some disagreements, I think, may stem from my failure to be sufficiently clear and so are only apparent. Other objections are not and seem to be spot on. I will not be able to give fully adequate answers to all the objections, since some require sustained discussion of some very fundamental issues that is simply impossible in this forum.

Response to Schliesser

Schliesser's comments concern (a) my discussion of philosophical and natural relations and their connection with reason, and (b) my reading of Hume's attitude regarding the external world.

In my reading of "reason" in Hume I make some abstract distinctions. We can think of reason as a faculty (reason_F) that is at once sensitive to normative considerations and explanatory of the inferences we make. We can further think of a reason as a normative consideration (a reason_N) that reason_F grasps and reasoning as the mental transition from idea to idea (reasoning_I). I also note that Hume talks of reasoning in a way that suggests that it is an activity of some sort. Thus, he writes that all "kinds of reasoning consist in nothing but a comparison, and a discovery of those relations, constant or inconstant, which two or more objects bear to each other" (T 1.3.2.2). In light of these distinctions, I then consider T 1.3.6, "Of the inference from the impression to the idea." A potential source of reasons_N comprises the philosophical relations that are the objects of comparison, detected by reason_F. But in fact this source yields no such reasons. Demonstrative reason has constant relations as its objects and probable reason the inconstant relation of causation. However, none of the available relations is such that it is a normative reason for the inference from cause to effect, and so no reason_N enters in the causation of our inference. So reason_F cannot be what causes reasoning_I since there are no reasons_N for it to discover or detect. Causal inference—reason_I—is causally determined, then, not by reason_F grasping reasons_N but instead by the natural associative relation of cause and effect. Hence, "Tho' causation be a philosophical relation, as implying contiguity, succession, and constant conjunction, yet 'tis only so far as it is a natural relation, and produces an union among our idea, that we are able to reason upon it, or draw any inference from it" (T 1.3.6.16; SBN 94). Schliesser writes I offer no textual support for these claims (000), but I am a bit puzzled by what it is he is demanding and what I am missing. The distinctions are mine of course, and I consider Hume's texts in the light of them. I take them to illuminate his text, so I am not sure what is required. Let me, however, take his three criticisms head on.

First, he points to texts that, if I have him right, suggest that probable inference need not involve any reflection upon causation qua philosophical relation. The first passage he cites (70) reads "'Tis therefore necessary, that in all probable reasonings there be something present to the mind, either seen or remember'd; and that from this we infer something connected with it, which is not seen nor remember'd" (T 1.3.6.6; SBN 89). I do not see this as in conflict with my suggestion, which was that it is necessary that associational tracks are in place in order to reason. Hence causation is a philosophical relation, but "we are [not?] able to reason upon [that relation], or draw any inference from it" (T 1.3.6.16; SBN 94). Indeed Schliesser writes later (70) that "philosophical relations are rather impotent without the presence of the appropriate natural relations," and I write Hume holds that "our capacity to reason upon the philosophical relation of cause and effect presupposes that we have habits of inference" (Kail, 42-43).

Perhaps more potentially threatening to my...