Hume's Empiricism: Knowledge, Morality, and Politics

The Problem of Knowledge: Epistemology

Hume is the most important author of the school of empiricism. Empiricism states that all our knowledge comes from experience. Hume denies the existence of innate ideas in reason, prior to experience, since our mind is like a blank page on which nothing is written at birth (tabula rasa).

He distinguishes two elements of knowledge (or "perceptions"): impressions, more vivid mental representations received by the senses (external or internal); and ideas, which are representations or copies of past impressions in the mind, characterized by being less lively. Both impressions and ideas can be simple or complex.

Ideas can be associated or connected according to three basic laws: the law of similarity, the law of contiguity (spatial and temporal), and the law of causality (although reduced to "temporal continuity").

Also, based on Leibniz, Hume asserts that there are two types of knowledge:

- Knowledge of matters of fact, dealing with what we believe exists in the world. The standard of "truth" requires that all ideas can be traced to a more lively original impression. Any fact is possible (the law of contradiction does not apply): "The sun will rise tomorrow" is just as possible as "the sun will not rise tomorrow" (although the former is more credible due to custom).

• Knowledge of relations between ideas, which refers to demonstrations and statements of mathematics and logic. Their contents can be known through reason, whether they exist in the universe (Hume denies the existence of Cartesian res extensa). They constitute the only "necessary" knowledge, and their criterion of truth is governed by the "principle of contradiction," but they have no connection to experience. Hume reduces the problem of empirical truth to its psychological, genetic, and subjective components (vividness).

Hume criticizes the structures that supported the reality and truth of classical, medieval, and rationalist philosophy (expressed by Plato as the epistemological distinction "appearance/truth"). In the Middle Ages, these were ontologically expressed in World substances, Soul (I), and God. Hume's moderate skepticism, phenomenalism, and nominalism reduce substances and laws of the universe (with its different types of "causation") to a set of "psychological" principles (laws of association of ideas). He avoids radical skepticism by assuming (without justification) that these belong to a uniform and common "Human Nature," based on emotion rather than reason (despite criticizing any substance not limited to atomistic impressions). He assumes as a fact, unexplained, the consistency, regularity, and uniformity in the connection of those impressions for all human subjects, which allows us to believe in the existence of the World and Humanity who knows.

Hume criticized the three Cartesian substances (the self, external reality, and God) and asserted that it is impossible to know (rationally explain) their existence.

He denied the claim of the existence of the self understood as a permanent and stable identity, a substance or essence. It is impossible to have an impression (or intuition) of the permanent and stable. Our "I" is nothing more than the succession of impressions occurring in our mind that our memory recalls (without explaining how and why, as Plato tried) and illegally unifies beyond atomistic experience.

To assert that we cannot know if there is a large Substance (World) is based on his criticism of the idea of cause. Unable to say without doubt that our impressions come from something outside, we cannot ensure the existence of external reality. Therefore, we cannot know for sure if there is extra-mental reality (phenomenon).

He also indicated that we cannot ensure the existence of God, as it is impossible to experience it and therefore cannot prove its existence (a priori or a posteriori).

Hume, who knew the works of Newton, examined the scientific claims that employ the principle of causality (understood as a binary and necessary connection between cause and effect). According to Hume, we cannot have any impressions of the connection (we cannot perceive that something will always happen). For Hume, cause-effect is affirmed by the experience of perceiving one event as normal after another. Therefore, we believe that what has happened in the past will be repeated in the future, and similar objects (assuming likeness as an unexplained fact) will have similar effects in the future. The truth of every law of nature would, therefore, only be probable. However, Hume accepts the usefulness of these beliefs for life, and therefore science itself is useful for humanity.

Ethics, Morality, and Politics

For Hume, our moral judgments are not produced by reason. They are not necessary relations between ideas or based on matters of fact because moral judgments do not describe an event (they do not refer to a "being"). Instead, they are activities that consider something "good or bad" (justifiable). Reasoning may help clarify the utility or the precise means of human actions, but according to Hume, it cannot determine the purposes and impulses to achieve them. Therefore, reason cannot be the foundation of morality. Instead, it is the feeling (emotion, passion) of approval or disapproval of the individual. This moral feeling is an internal emotion or "taste" that arises in individuals, showing their pleasure or displeasure at actions. This taste is universal, common to all humans, and useful for Humanity (he does not appreciate the dialectic between various groups and corporations). It expresses the sympathy ("natural match of feelings of all mankind"). Hume defends a moral theory known as "moral emotivism."

Regarding the origin of society and politics, Hume opposes "contract" theories (as proposed by Hobbes, Locke, and Rousseau), which account for men in a state of nature resolving rationally to form society. Hume thinks that this association reflects a desire (similar to the desire to unite male and female). Society and its institutions (justice, government, etc.) are not legitimate "by nature" of previous rational individuals but for their useful "conventional" (emotional) nature. A simpler society without government is possible (as with American Indian tribes). The increase in individual wealth and property requires, for its utility, the formation of governments to defend property and justice, whether its introduction is violent or not. The important thing is that the government is useful for maintaining social persistence. If it does not fulfill that function, there is no reason to obey. He advocated a kind of "mixed monarchy" that combines royal government (in the figure of the King), aristocracy (expressed in the Tory party), and the Republic (or democracy, through the Whig party), collecting Thomist ideas.