David Hume’s Treatise of Human Nature

Hume’s most influential work was broken down into three books and covered a wide range of philosophical subjects.

Hume argues that empiricism, the notion that all knowledge comes from experiences, is valid and that ideas are essentially no different from experiences because complex ideas are the result of simpler ideas, and the simpler ideas were formed from the impressions our senses created. Hume then also argues that when something is a “matter of fact,” it is a matter that has to be experienced and cannot be arrived at through instinct or reason.

With these arguments, Hume takes on the notion of God’s existence, divine creation, and the soul. According to Hume, since people cannot experience or get an impression from God, divine creation, or the soul, there is no real reason to believe in their existence.

It is in his first book that Hume introduces three tools used for philosophical inquiry: the microscope, the razor, and the fork.

  • Microscope: In order to understand an idea, one must first break down the idea into the simplest ideas that it is made up of.
  • Razor: If a term cannot come from an idea that can be broken down into simpler ideas, then that term has no meaning. Hume uses the notion of the razor to devalue ideas such as metaphysics and religion.
  • Fork: This is the principle that truths can be separated into two types. One type of truth states that once ideas (such as a true statement in math) are proven, they remain proven. The other truth relates to matters of fact and things that occur in the world.

In Hume’s second book, he focuses on what he refers to as passions (feelings like love, hatred, grief, joy, etc.). Hume classifies passions like he classifies ideas and impressions. He first makes a distinction between original impressions, which are received through the senses, and secondary impressions, which come from original impressions.

Original impressions are internal and from physical sources. They appear in the form of physical pains and pleasures and are new to us because they come from physical sources. According to Hume, the passions are found in the world of secondary impressions. Hume then makes the distinction between direct passions (like grief, fear, desire, hope, joy, and aversion) and indirect passions (like love, hatred, pride, and humility).

Hume states that morality is not based on reason because moral decisions affect actions, while decisions made from reason do not. An individual’s beliefs in regard to cause and effect are beliefs relating to the connections among objects that people experience. The actions of an individual are affected only when the objects are of interest, and they are only of interest to people if they have the ability to cause pain or pleasure.

Therefore, Hume argues, pleasure and pain are what motivate people and create passions. Passions are feelings that initiate actions, and reason should act as a “slave” to passion. Reason can influence an individual’s actions in two ways: It directs passions to focus on objects, and it discovers the connections among events that will eventually create passions.

Based on the ideas he set forth in his first two books, Hume takes on the notion of morality. First, Hume distinguishes between virtue and vice. Hume claims these moral distinctions are impressions, not ideas. While the impression of virtue is pleasure, the impression of vice is pain. These moral impressions are only the result of human action and cannot be caused by inanimate objects or animals.

Hume argues that an individual’s actions are only determined to be moral or immoral based on how they affect others (and not how they affect the individual). Therefore, moral impressions should only be considered from a social point of view. With this notion in mind, Hume claims that the foundation of moral obligation is sympathy.

Morality is not a matter of fact that is the result of experience. Hume uses murder as an example. If one were to examine murder, one would not experience pain, and therefore, one couldn’t find the vice. You would only uncover your own dislike of murder. This shows that morality does not exist in reason, but rather, in passions.

Because of David Hume’s criticism of philosophical theories, ideas, and methodologies that relied heavily on rationalism, he became one of the most important minds in Western philosophy. His work touched on an incredible number of philosophical topics, including religion, metaphysics, personal identity, morality, and concepts of cause-effect relations.