History of Modern Ethics
Stephen Darwall
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Hume Lecture 1

I. David Hume is often praised as the greatest philosopher ever to write in English. In addition to his philosophical works, including most prominently, A Treatise of Human Nature (1739,40), Hume published essays on many topics, and wrote a History of England of several volumes which was the standard English history for a very long time.

II. An aim of Hume’s in the Treatise is to discover the foundation of ``moral distinctions''. He is famous for arguing that morality cannot derive from reason. Before we consider his arguments for this view we need, first, to consider his arguments in Part III, Section III of Book II for the proposition that reason cannot provide any motive for action.

Let us begin with Hume's first paragraph:

``Nothing is more usual in philosophy, and even in common life, than to talk of the combat of passion and reason, to give the preference to reason, and to assert that men are only so far virtuous as they conform themselves to its dictates. Every rational creature, 'tis said, is oblig'd to regulate his actions by reason; and if any other motive or principle challenge the direction of his conduct, he ought to oppose it, 'till it be entirely subdu'd, or at last brought to a conformity with that superior principle.'' [Query: Who does it sound like hume is describing?]

Notice first that Hume identifies reason with the understanding, and defines it as including reasonings of two sorts--demonstrative and probabilistic [notice the affinities to Hobbes ('reckoning') and Hutcheson, and compare with Butler]. The first sort ``regards the abstract relations of our ideas'' and the second concerns inferences we make from experience using the principle of cause and effect. Hume's view is that neither of these can, by themselves, create a motive for a person to do anything. Therefore, reason cannot directly motivate action. Therefore, there can never be a conflict between passion and reason. ``Reason is, and ought only to be, the slave of the passions, and can never pretend to any other office than to serve and obey them.'' (415)

Crudely put, Hume's picture is this. Through reason we can only infer beliefs about the way things are. But whether we are moved by these beliefs depends on whether we have desires to which these beliefs are relevant. We cannot be moved by beliefs directly. For example, if I want a new winter coat at a reasonable price, I may be moved by the belief (which we may suppose that I acquire by reasoning from my experience) that I can get such a coat from the Land's End catalogue. But another person reasoning to the very same belief, but without the desire, will not be motivated.

As it turns out, this picture is not wholly Hume's. For he explicitly says that some beliefs are such that if we come to have them, we cannot help but be given desires which motivate. And so these beliefs motivate, even if at one remove. ``'Tis obvious, that when we have the prospect of pain or pleasure from any object, we feel a consequent emotion of aversion or propensity, and are carry'd to avoid or embrace what will give us this uneasiness or satisfaction.'' (414) What should we say about this apparent exception?

Hume has another argument for holding that neither actions or passions can be contrary to reason. According to Hume's definition of reason, something can be contrary to reason only if it can be false, or mistakenly inferred. But, he says, neither actions nor passions can be contrary to reason in this sense since they aren't even the sort of thing which can be false (or inferred). Something can be false only if it has a ``representative quality,'' i.e., if it purports to represent reality in some way, and if it represents falsely. But passions and actions have no such quality--each is an ``original existence'' (415) and ``compleat in themselves'' (458). Therefore, they can neither be false, nor mistakenly inferred. Therefore, they cannot be contrary to reason.

We should note here that Hume is really arguing for two different theses which he tends not to separate: (a) passions cannot be contrary to reason in the sense that they can never have opposing motive force, because reason can never motivate by itself; (b) passions and actions cannot be contrary to reason in the sense that reason cannot criticize passions and actions. Strictly speaking, reason can only criticize beliefs and patterns of thought leading to beliefs, viz., if a belief is false or mistakenly inferred. It is important to keep these claims separate, even if Hume tends to run them together. [Be prepared, by the way, for a similar ambiguity in Hume's claim in Book III that moral distinctions cannot derive from reason. Sometimes he means that reason cannot, by itself, discover moral distinctions. Sometimes he means that moral distinctions cannot be based on whether actions or passions are in accord with or contrary to reason (in the second sense).] One way Hume puts his second claim is that actions and passions cannot be, in themselves, either reasonable or unreasonable. (e.g., 458) There is an extended sense in which we may call a passion unreasonable if it meets either of two conditions: (a) if the passion ``is founded on the supposition of the existence of objects which really do not exist,'' or (b) ``when in exerting any passion in action, we chuse means insufficient for the design'd end, and deceive ourselves in our judgment of causes and effects.'' In either of these cases we may call the passion unreasonable, but ``properly speaking'' it is the belief that is unreasonable, not the passion.

Assuming no mistaken beliefs, ``'Tis not contrary to reason … former than the latter.'' [Query: compare this passage with 414 where Hume says that beliefs about the prospect of pain and pleasure unfailingly give rise to passions. Is there any tension between them?]

II. Next time we will examine Hume's arguments in III, I, i for the proposition that moral distinctions cannot derive from reason. One of his most influential arguments for this claim depends on his conclusion from Book II that reason can provide no motive to action by itself. His idea in Book III is that morality is, in some way, intrinsically motivating. Because it is, he thinks that it follows that no moral proposition can be concluded by reason alone, since any conclusion of reason cannot motivate by itself.

Exactly how this argument is supposed to work is not entirely clear. First, it is not clear what link between morality and motivation Hume is asserting. He says that morals ``naturally'' ``have an influence on the actions and affections'' (457, lines 6, 18). But what does he mean by that? We might begin by considering what he cites as evidence: ``common experience … informs us, that men are often govern'd by their duties…'' This evidence, however, is compatible with the hypothesis that moral distinctions can be discovered by reason though reason can provide no motive. It might be that a desire to be moral is nurtured by society, and this desire motivates moral action in many people. Pretty obviously, Hume must be rejecting this picture. He must be saying that the connection between morality and motivation is closer. What is he saying?

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