David Hume opens Treatise 1.4.3, “Of the Antient Philosophy”, with a curious analogy, intended to explain why it is that he is about to investigate questions about various “unreasonable and capricious” categories prominent in what Hume is calling “antient” philosophy:
Several moralists have recommended it as an excellent method of becoming acquainted with our own hearts, and knowing our progress in virtue, to recollect our dreams in a morning, and examine them with the same rigour, that we wou’d our most serious and deliberate actions. Our character is the same throughout, say they, and appears best where artifice, fear, and policy have no place, and men can neither be hypocrites to themselves nor others. The generosity, or baseness of our temper, our meekness or cruelty, our courage or pusilanimity, influences the fictions of the imagination with the most unbounded liberty, and discover themselves in the most flaring colours. In like manner, I am persuaded, there might be several useful discoveries made from a criticism of the fictions of the antient philosophy, concerning substances, and substantial forms, and accidents, and occult qualities; which, however unreasonable and capricious, have a very intimate connexion with the principles of human nature.
Here, Hume is pre-emptively answering the question: “What is the point of spending time talking about the categories substance, substantial form, etc., if it is clear that they are false, unreasonable, fictions?” While Hume’s talk of “useful discoveries” might initially suggest something like a position where the antient philosophy has some truth mixed in with its falsehood, and so, investigation of the antient philosophy will help us extract those truths (cf. what Pasnau calls the “high-road” response to the progress dilemma), I think the rest of 1.4.3 makes it clear that what Hume is really after, in investigating these philosophical fictions, is to learn about the basis in human nature for positing them. In other words, we’re studying the fictions of false philosophy in order to learn about the minds that posit it, rather than about the subjects it attempts to explain. And that this is Hume’s answer should not surprise us; Hume frequently directs us to change our inquiry from object- or world- oriented questions and focus instead on thinker- or mind- oriented questions. In 1.4.2, for instance, we are told it would be in vain to ask “whether there be body, or not?”, but can more profitably ask “what causes induce us to believe in the existence of body?”. So, Hume’s view of what we can hope to get out of investigating antient philosophy is straightforward, and it coheres well with Hume’s strategy in the Treatise.
What remains curious, however, is the analogy Hume offers. I can see the proposed parallel here: The “moralists” Hume references are saying that dreams, despite not being a good guide to reality, can be very informative about the person who has them, just as these false philosophical categories, despite not being a good guide to the structure of the world, can be very informative about the nature of the minds that find them so appealing. When I first started writing this post, I wasn’t especially sympathetic to the view that Hume attributes to “several moralists”, and so I thought the analogy was curious insofar as it seemed to be invoking a weird view to explain a fairly straightforward one. Actually articulating the proposed parallel has softened me some towards the view (and thus the analogy), but I am still left with a question: For the case of looking to dreams to learn about someone’s character, it is supposed to be the absence of “artifice, fear, and policy” in the dreams that renders them so informative about the character of the dreamer; is there something similar to be said about for the case of antient philosophy? In other words, how strong is the analogy supposed to be? Does it simply rest at the parallel of using products of the mind to learn about the thinker that produces them, or is there something further to the analogy, that explains why the fictions of antient philosophy are especially good sources of information about human nature?