Reason has to be about something, and clearly other factors, such as our knowledge of facts, are also involved in morality and practical reasoning (on which Hume wrote extensively). For reasoning to be influential in our lives and decisions, moreover, it has to sway people’s actual sentiments. (On this Hume also said a great deal.) This understanding can be seen in the context of delineating the way reasoning can work. These exercises of delineation do not in themselves undermine the important role of reasoning in ethics, nor entail any denial of the usefulness of reasoned argument about what we actually do know, or what our sentiments really are, or what they could be expected to be after critical scrutiny.

Hume had much use for reason whenever it could be sensibly deployed. The totality of his works richly illustrates his reason-dependent approach. While Hume expressed his frustration that “avidity alone, of acquiring goods and possessions for ourselves and our nearest friends” might well be “insatiable, perpetual, universal, and directly destructive of society,” or that people very often are too guided by self-interest in their thinking about justice, he also argued that there could be “moderation and abstinence” based on a reasoned understanding of the mutual dependence of people on each other. He points out, for example, that people “pull the oars of a boat by common convention for common interest, without any promise or contract,” and that their sense of justice is developed by thinking in “company and conversation.” The recognition that much of practical reasoning is conducted in company—a point that Gramsci would emphasize powerfully in his essays inL’Ordine Nuovo two centuries later—does not undermine the role of reasoning, but helps to characterize how it tends to occur.

The characterization also includes Hume’s treatment of what he called “experimental reasoning … which we possess in common with beasts, and on which the whole conduct of life depends.” At one level, this is, as Hume argued, “nothing but a species of instinct or mechanical power.” But experimental reasoning does not imply any absence of reasoning. The instinct that makes a person reluctant to put his or her hand into the fire is, as Hume discussed, both an instinct and an example of a species of reasoning. The instinct to keep our hand out of the fire is not unrelated to our seeing—and learning from others—what happens if an object like a hand happens to go into the fire, and this is what experimental reasoning is about. The net effect of this dual role is to extend the reach of reasoning—even to animals (the discussion cited here comes in an essay called “Of the Reason of Animals”)—rather than to deny that this type of decision could be compatible with any kind of reasoning since it is, in an immediate sense, just an instinct.

SIMILARLY, HUME’S insistence that the reach of ethical reasoning is, of necessity, limited is also a part of this delineation. Indeed, Hume thought that reasoning has a confined reach even in central issues of epistemology. We may not ever be able, as Hume points out, to “satisfy ourselves concerning any determination, which we may form, with regard to the origin of worlds, and the situation of nature, from, and to eternity.” But this did not prevent Hume from trying to see what can be sorted out through reasoning. Indeed, it is these efforts of reasoning that made Hume such a suspicious character to the religious establishment of his time. We have reason to pursue knowledge to the extent we can, undeterred by the recognition that we may not be able to resolve all the issues that arouse our interest and curiosity.