History of Modern Ethics
Stephen Darwall
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Hume Lecture 2

I. Hume argues in Treatise II.iii.3 that: (a) reason cannot motivate by itself (since reason only enables us to form beliefs (demonstratively or probabilistically), and whether an individual is motivated by any particular belief depends on her desires; (b) no action or passion can be criticized by reason (since only what can be true or false can be).

II. Hume makes use of these claims in Part I, Section I of Book III, in which he aims to show that ``moral distinctions'' are ``not deriv'd from reason''. But just as we had to be careful last time to distinguish two distinct senses in which Hume was arguing that reason could not oppose passion, so this time we will need to attend to two different things that Hume tends to run together in arguing that moral distinctions cannot derive from reason. Sometimes what he is claiming is that an action or passion cannot be morally bad in virtue of being contrary to reason. At other points the thesis he has in mind is that no moral proposition can be discovered by reason. We should note that these are strictly independent theses. It could be false that, say, if an act is wrong that is because the act is contrary to reason or unreasonable and still be true that reason can discover the truth of the proposition that it is wrong. It would, of course, then be true that a person would be acting contrary to a moral injunction whose truth could be grasped by reason. In that sense he would be acting contrary to reason. But it would still not necessarily be true that what made his so acting wrong would be that he was acting contrary to reason. On the contrary, he would be acting contrary to reason because of the possibility of grasping the independent fact that his act was wrong.

Hume was not making a simple confusion in running these two together. Many rationalists who had argued that reason could discover moral truth had also held that moral truth depends on reason. Thus, the great early 17th C natural law theorist, Hugo Grotius, had argued that reason can know the natural law and that the natural law expressed dictates of reason itself. And rationalist contemporaries of Hume's in Britain, such as Samuel Clarke and William Wollaston, held similar positions. Indeed, it might not be too far wrong to say that arguing for these two claims together is the best hope a rationalist has.

III. We can deal pretty quickly with Hume's arguments that moral distinctions cannot be based on rational ones, that is on some kind of falsehood or error.

A. Hume's first argument is simply a repetition of his argument from Book II that no passion (and, now, no action) can be contrary to reason because only something which is capable of being true or false can accord with, or be contrary to, reason. (458)

B. He then goes on to point out that, while there are two extended senses in which we can call an action or passion unreasonable, neither of these seem to be related to whether it is laudable or blameworthy. Thus, a passion may be said to be unreasonable if it is based on a mistaken belief about its object (say, about whether it exists). Or an action may be said to be unreasonable if it derives from a mistaken belief about what means there are to accomplish various ends. [Of course, Hume's prefers to say that in these cases it is really the basis belief, and not the consequent passion or action, which is strictly speaking unreasonable.] But in neither case are we likely to hold that these sorts of unreasonableness are any basis for holding a passion or action to be morally bad:

``these errors are so far from being the source of all immorality, that they are commonly very innocent, and draw no manner of guilt upon the person who is so unfortunate as to fall into them.'' (459)

Additionally, he observes that if immorality derives from unreasonableness, then it should attach as much to judgments ``concerning an apple'' as much as one concerning ``a kingdom''.

C. He finally considers the possibility that actions become morally criticizable by virtue of bringing about unreasonable beliefs as effects. (461) One may well wonder why he sees fit even to consider this possibility, but he takes this view to have been held by a writer ``who has had the good fortune to obtain some reputation'', viz., William Wollaston. In fact, this was not Wollaston's view. He held that actions express beliefs, and that when they express false beliefs they are wrong by virtue of that. So, he thought, when someone lies, in addition to the propositions she asserts, she also implicitly asserts that these propositions are true, that she believes them to be true, and so on. Because these implied beliefs are false, her action is wrong. Or a thief, in stealing someone else's property, implicitly asserts that the property belongs to him (the thief). Because this is false, the action is wrong.

Now Hume does not argue against these claims of Wollaston's. Instead, he argues against the thesis that an action cannot be wrong by virtue of creating false beliefs as a consequence. Although Hume's example of ``a person, who thro' a window sees any lewd behaviour of mind with my neighbour's wife'', and who thereby sees something wrong, although hardly by virtue of having a false belief, is arguably more titillating, I confess to being partial to the example he mentions in 462n of ``squint-sighted persons'' who are hardly immoral by virtue of appearing to address one person when in fact they are addressing another. Those of you who have had the pleasure of wondering whom I was calling on when you had your hand in the air may appreciate why this is so. In any case, we need not bother much with the possibility of an action or passion being wrong by virtue of being contrary to reason given what Hume is willing to countenance as ways in which something may be contrary to reason. If reason simply is ``the discovery of truth or falshood'', then he must be right. But is this indeed the way we should think of reason? Here we should think back to Butler and the line of thought which links the having of a certain kind of reflectively motivating capacity to the capacity to act for justications or reasons. And we shall encounter a similar, if still quite distinct and original thesis when we come to Rousseau, and, again, to Kant. In each case we need to think of which picture is more compelling, bearing in mind that not much can possibly hang on whether we call these reason or not.

IV. By far the most influential of Hume's arguments for the claim that morality cannot derive from reason depends on his thesis that morality is inherently motivating in a way that no state deriving from reason, no belief, can possibly be. Reason can never motivate, by itself, whereas morality is, Hume seems to say, intrinsically motivating, at least to some degree.

Now, while this idea has been extremely influential, it is also pretty murky, and hard to state precisely. At the end of the last notes, I noted that Hume's evidence for his claim, ``that men are often govern'd by their duties, and are deter'd from some actions by the opinion of injustice, and impell'd to others by that of obligation'', seems fully consistent with there being nothing intrinsically motivating either in moral convictions or judgments, or in morality itself. Nonetheless, Hume is usually taken to be arguing that moral judgments are intrinsically motivating. So understood, he is taken to argue somewhat as follows:

(1) The judgment that some act is wrong, or that some passion is vicious, is intrinsically motivating in the sense that a person so judges only if she is motivated (or would be under certain conditions) against the action or passion to some degree.

(2) Reason can only lead us to beliefs that such-and-such is the case, and no such belief is intrinsically motivating in this sense.

(3) Therefore, no moral judgment can derive from reason.

Although Hume doesn't draw any further conclusions, Humean philosophers have drawn such further conclusions as

(3)' Therefore, no moral judgment is a belief. (3)'' No moral judgment can be true or false.


V. While this is the usual way of understanding Hume, he rarely expresses himself in terms that suggest (1). He is as likely to say, somewhat cryptically, that ``morals'' or ``the distinction betwixt moral good and evil'' can themselves influence conduct. Note the following:

``If morality had naturally no influence on the passions . . . '' [he is suggesting it does] (457)

``morality . . . 'tis supposed to influence our passions and actions, and to go beyond the calm and indolent judgments of the understanding.'' (457)

``morals, therefore, have an influence on the actions and affections.'' (457)

``morals excite passions, and produce or prevent actions'' (457)

And, in the passage where he is arguing that actions and passions cannot be contrary to reason in the other sense, he throws in:

``as reason can never immediately prevent or produce any action by contradicting or approving of it, it cannot be the source of the distinction betwixt moral good and evil, which are found to have that influence.'' (458)

``The merit or demerit of actions frequently contradict, and sometimes controul our natural propensities. But reason has no such influence. Moral distinctions, therefore, are not the offspring of reason. Reason is wholly inactive, and can never be the source of so active a principle as conscience, or a sense of morals.'' (458)

Note how in the very same passage here Hume says both that ``the merit or demerit'' of actions can itself influence, and that the influence derives from the ``sense of morals''.


VI. We can actually get some idea of how his thought is moving here by looking at another argument he gives for why moral distinction cannot derive from reason. This is after he has drawn a contrast between demonstrative reason, which can lead us to knowledge about the relations between ideas, and probabilistic reason, which leads us to knowledge of matters of fact. He describe an example in an arresting way. The sort of things Hume says about this example (at 468), and across the page in his famous ``Is/Ought Passage'' (469) have led his readers to suppose him to be drawing a contrast between matters of fact, on the one hand, and matters of value, on the other--between `is''s and `ought''s--the thought being that reason can only enable us to discover facts, not values--`is''s, not `ought''s. Whether that is so or not, consider what he says on 468:

``Take any action allow'd to be vicious: wilful murder, for instance. Examine it in all lights, and see if you can find that matter of fact, or real existence, which you call vice. In which-ever way you take it, you find only certain passions, motives, volitions and thoughts. There is no other matter of fact in the case. The vice entirely escapes you, as long as you consider the object.''

Now what is the thought here? I think it is something like this. Whenever we evaluate something, we do so on the basis of its features, on the ``matter[s] of fact in the case''. But precisely because our evaluation is of the object, and based on its features, what value we take the object to have cannot itself be one of the object's features. Since its value rests on the matters of facts in the case, it cannot itself be another matter of fact in the case. Through our use of reason we can inform ourselves about the object of evaluation, about its features and the facts of the case. But this is all reason can do; it cannot additionally inform us of the object's value, or of a passion's morality, because that is not itself a feature of the object or a matter of fact of which we can be informed by reason.

But now notice Hume's suggestion about where we can look to find the viciousness of, say, murder:

``You can never find it, till you turn your reflexion into your own breast, and find a sentiment of disapprobation, which arises in you, towards this action. Here is a matter of fact; but 'tis the object of feeling, not of reason. It lies in yourself, not in the object.'' (468- 9)

Notice how Hume seems to say that the vice itself is in the spectator--it is his disapprobation. This is paradoxical, and not his most considered way of representing his views, but it may help to explain why he both says that moral distinctions and the ``sense of morals'' are motivating. It may be that, when he writes these things, he is thinking of the moral distinctions as existing by way of the sentiments aroused in a spectator.


``Nothing can be more real, or concern us more than our own sentiments of pleasure and uneasiness; and if these be favourable to virtue, and unfavourable to vice, no more can be requisite to the regulation of our conduct and behaviour.'' (469)

[N.B. as well, Hume's comparison of vice and virtue to ``sounds, colours, heat and cold, which, according to modern philosophy, are not qualities in objects, but perceptions in the mind.'' (469)]

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