A Treatise of Human Nature

Hume now describes the “direct passions” (447), which he defines as emerging straight from pain and pleasure or good and evil. These include grief/joy, fear/hope, and desire/aversion. This is also how Hume sees the will, which he views as one of the “immediate effects” (447) of pain and pleasure.

Hume considers the question of whether human behavior emerges out of necessity (reactions based on the impressions and ideas formed through sensations) or liberty (total free will). Hume notes one argument that necessity does not drive human behavior: “Necessity is regular and certain. Human conduct is irregular and uncertain” (451). To this, Hume responds that the process through which we develop our experiences and ideas in response to the physical environment around us is similar to how we respond to human behavior, which Hume calls “moral evidence” (452). The causes driving the behavior of individual humans do vary, but humans actually do consistently act based on our own individual experiences, interests, and needs.

From there, Hume challenges the philosophical idea of liberty. He lays out a series of three objections. First, Hume argues that there is a distinction between liberty of indifference (our freedom not being bound by necessity) and liberty of spontaneity (our freedom to act as we choose). Hume criticizes philosophers for not often making a distinction between the two (455). Second, Hume asserts that we have a “false sensation or experience” (455) of liberty. For example, we believe in hindsight that we could have chosen differently and not acted out of necessity. Third, we believe necessity contradicts the idea that people have moral responsibility and can be used as an excuse to violate religious morals and the law. Hume counters that there are no social dangers in acknowledging that impressions and relations influence human behavior (456-57). Instead, Hume argues that necessity supports the idea of an individual’s moral responsibility. After all, Hume’s concept of necessity shows that people’s behavior does not come from just chance, but instead reveals that each individual has a moral character that forms the basis of their actions (458).

Next, Hume turns to the circumstances that do shape our free will. Hume begins by arguing against the influential notion that reason and emotion are always at odds. Instead, Hume argues that we use reason as a tool to make our actions or determine our goals, all of which are shaped by our passions (461). A passion can be rational and pure reason itself is not always rational. As Hume puts it, “Tis not contrary to reason to prefer the destruction of the whole world to the scratching of my finger” (463). Hume admits that a passion can come from a cause that is false or a relation that is not reasonable. However, in that case, it is not the passion itself that is false, but the judgment connected to the passion (463). Hume goes so far as to say the conflict between reason and the passions is really the conflict between violent passions and calm passions (464-65).

With that, Hume discusses the violent passions and why they influence us. He lists a number of circumstances in which one predominant passion can be made more violent by other passions. For example, a man’s love for his mistress might become more extreme if he also feels a little anger or hate toward her, and a soldier’s bravery might be stronger if he feels some fear (467). Custom may also increase or deaden the power of violent passions. At first, the repetition of an experience might strengthen a passion, but also eventually make even a pleasurable activity painful (470-71). Also, the passions can become more violent through the “vivacity” (471) or strength of our ideas. One such idea that increases vivacity is space and time, since, for example, the further away in distance in time and space something is, the less intense our emotion. Similarly, we hold more respect for an object or person from a great distance, like an ancient Greek medal (480). Hume theorizes this is because we place our respect for a great distance in space or time into an object. Hume argues that we have more respect for objects associated with the past than the future because we cannot go against the flow of time toward the past while we are naturally headed to the future.

Hume concludes by looking at the direct passions. He identifies two types: the direct passions, which come from pleasure and pain or good and evil, and those that arise from instinct (485-86). The first kind includes joy and grief, hope and fear, and desire and aversion. The will asserts itself when someone seeks pleasure or to be freed from pain. The second kind of direct passions include hunger, lust, anger, and benevolence. These do not arise from pleasure and pain, but they can cause pain and pleasure. Hume focuses on fear and hope. Passions of joy and grief are generated when the imagination examines different possibilities and “the chances are equal on both sides” (490). Depending on the object of the passions, the combination of grief and joy will produce either hope or fear.

The last passion Hume examines at length is curiosity, which Hume describes as “love of truth” (495). Curiosity is driven by our pleasure in seeking truths in either abstract subjects like mathematics, or in tangible areas like politics and natural philosophy. Such curiosity is made more vivid by our desire for an intellectual challenge and by our sympathy for those our research or scientific discoveries might help. Hume also argues that our curiosity is propelled by the pleasure we gain from the work itself, much like how a gambler might enjoy the distraction of the game more than even the challenge or the awards from winning (498-99).