Reason Is and Ought Only to Be the Slave of the Passions

From Hume on the Emotions in Stanford Encyclopedia of Philosophy

7. “Reason Is and Ought Only to Be the Slave of the Passions”

One of the most notorious of Hume’s views about the passions concerns their relation to our practical reason. Hume locates our motivations in the passions. As noted in section 4, he treats the will in his discussion of the direct passions, identifying it as “the internal impression we feel and are conscious of, when we knowingly give rise to any new motion of our body, or new perception of our mind” (T II.3.1 399). If the will did not determine a person’s actions, we would have no way to trace those actions to their springs in character, which is the prerequisite for forming moral judgments.

Hume is particularly concerned with analyzing our practical reasoning, our reasoning about how to act. Passions are the engine for all our deeds: without passions we would lack all motivation, all impulse or drive to act, or even to reason (practically or theoretically). This gives at least one sense in which “reason is, and ought only to be the slave of the passions” (T II.3.3 415). Hume also holds that the passions are not themselves directly subject to rational evaluation. In fact, it seems something of a category mistake to think that they could be either rational or irrational. Passions are impressions – strong and lively perceptions with a certain “feel” and a direction, or impulse. Reasoning, however, is a matter of connecting various ideas in order to come to a belief; it may apply to, or even form, the circumstances under which passions arise. But reason can generate no impulse by itself.

On these grounds, many have attributed to Hume a belief-desire model of practical reasoning, in which our ends are given by passions (desires). On this view, reason is in the business of producing beliefs, but our beliefs are relevant only to the means by which we seek to obtain those ends: they do not determine the ends themselves. So, reason has only an instrumental use. But whatever its other virtues, this model does little to explain why reason “ought to be” the slave of the passions. It also seems inappropriate to reduce passions to desires: passions have a great deal more structure than their attractive or aversive directions, important though those may be. What seems central to Hume’s view is the inertness of reason, its inability to generate impulses for the mind (see Millgram 1995; for a different view that stresses the inertness of reason and representational states in general, see Radcliffe 2018). It is the inertness of reason that drives Hume to adopt a sentimentalist basis for the origins of our “moral distinctions” (T III.1.2).