This page is a brief and basic introduction to a few summary points about David Hume's life and philosophy. It is no substitute for an original source by the philosopher or a more in depth analysis by experts in his work. The following summaries and quotes of Hume's ideas can be found in An Enquiry Concerning Human Understanding, Hume, secs. I-V.

---

David Hume- (1711-1776) Scottish philosopher and historian, noted for his skepticism. He was born and educated in Edinburgh, and spent three years in France where he wrote the first draft of A Treatise of Human Nature (1734), which was later published in 1739. Known for his diverse examination of philosophical topics, Hume wrote many other titles, including a number of commonly cited essays. An Essay on Human Understanding, among them, written in 1784.

Two species of Philosophy: The first species of philosophy that Hume recognizes are those that consider man "chiefly as born for action." The second species include those that look at man "in the light of a reasonable rather than an active being," and subsequently attempt to further understanding rather than manners.

Hume thinks that we should "cultivate true metaphysics with some care" to the end that we find what we can and can not know. To do this, we must overcome false philosophy and see through "metaphysical jargon" . This jargon, if combined with popular superstition, may become susceptible to careless reason and appear scientific and wise. To avoid this, we must use accurate and just reasoning.

Ideas and Impressions: According to Hume, Ideas are the less forceful and vivid perceptions of the mind, while Impressions are the more lively perceptions when we do such things as hear, feel, or love. The difference between an idea and an impression is apparent when we reflect on such things as hearing, feeling, or loving. The less lively perceptions that we are conscious of are the ideas, while the more lively or vivid perceptions that we are conscious of are impressions.

Three Connections Among Ideas: Hume states that there are "three principles of connextion among ideas" . The first principle of connection among ideas is Resemblance, which is when one thing, such as a photograph of a car, leads our thoughts to the original, or the actual car itself.

The second is Contiguity, which is when one thing in something, such as a theory in physics, naturally leads to the other things in something, such as another theory in physics. The third is Cause and Effect, which is when one thing leads our thoughts to another in sequence, such as when we think of a large asteroid hitting the Earth we naturally think of the consequential devastation.

The Two Species of Philosophers in Detail: Hume’s two species of philosophy are categorized by how each of them sees man; either born for action or considering him in the light of reason. The first group, or the ones who see man as born for action, are those who study man’s pursuit of one object or another.

They look at where our emotions lead us, what we consider to have virtue, and borrow their ideas from literature and imagination. These philosophers examine striking examples from everyday life, and with them, lead men by the notions of glory and happiness. They create in us a feeling of right and wrong; they excite and regulate our emotions. (These are the artists.)

The second group, or the ones who study man in the light of reason, are those who speculate about man and examine him with scrutiny. These are the philosophers who believe that the principles behind man’s emotions and behind our understanding are deducible. They want to find the foundations of our condition rather than study the condition itself, as do the first group.

The use reason and science, "proceeding from particular instances to general principles" (induction), and push on until they reach the limits of human curiosity. These are the philosophers who try to discover hidden truths. (These are the scientists.)

Hume thinks that the first group, or those who see man as born for action, will always bee more agreeable, more preferential to mankind because it enters into the heart and emotions, and brings men nearer to a model of perfection. The second group, which Hume says, "vanishes when the philosopher leaves the shade" and can not influence the conduct and behavior of man. Our affections and our passions reduce these profound philosophers to "mere plebians".

In terms of everyday life, Hume thinks that as man is a reasonable being, science has an important place. But, we are so confined in terms of our understanding, that science can not, and should not satisfy us alone. Hume sums up his ideas in the lines, "Indulge your passion for science, says she, but let your science be human, and such as may have a direct reference to action and society...Be a philosopher; but, amidst all your philosophy, be still a man."

Ideas and Impressions in Detail: Hume believes that his definition of an "idea" is not innate, but his definition of an "impression" is innate. Hume believes that Locke’s use of the word "idea" was too broad a term, covering all of our perceptions, sensations, or passions. Also, Hume discusses the notion of "innate" in Locke’s philosophy as being unclear.

If innate means natural, or opposite of artificial, then it must be that all of the perceptions of the mind are innate. But, if innate means before birth, then nothing is innate because this is a frivolous argument, as Locke would assert. Also, it is not important, in Hume’s view, to inquire at what time thinking begins, before or after birth.

An "impression", in Hume’s philosophy, includes self-love, resentment of injuries, and passions between the sexes, which do seem to be innate. These may be similar to the reflexes that Locke allowed to be innate in his essay, "For, bating, perhaps, some faint ideas, of hunger, of thirst, and warmth, and some pains, which they may have felt in the womb..." Hume’s "ideas" or feeble perceptions, are copies of our impressions, or more lively perceptions, are not innate.

He gives an example to show how ideas are not innate by showing that a blind man has no notion of colors; and a deaf man no notion of sounds. It is interesting that he points out a possible, but unimportant flaw in this example by demonstrating how a man that has seen every shade of blue but one shade can create or imagine that deficit shade. (This may have more to do with the amount of light imagined hitting the color than the color itself.)

Two Kinds of Objects of Human Inquiry: Hume divides all the "objects of human reason or inquiry" into two kinds. The first kind, Relations of Ideas, includes intuitively certain propositions that expresses relation, such as the proposition one side of a square is the same length as the other four sides.

The second kind, Matters of Fact, includes those propositions that can never include a contradiction, such as the oceans will be there tomorrow. This does not contradict or make unintelligible the proposition the oceans will not be there tomorrow.

The one object of reason or inquiry that is founded upon one of Hume’s three principles of connection among ideas is Matters of Fact. This is founded upon the principle of connection called Cause and Effect, because when a proposition is a matter of fact, it comes from our experience of the relation between "...the present fact and that which is inferred from it."

Two Kinds of Reasoning: All reasonings can be divided into two kinds. The first is demonstrative reasoning, which is associated with the kind of Objects of Reason called Relations of Ideas. The second is moral reasoning, which is associated with the kind of Objects of Reason called Matters of Fact.

Hume explains the difference between the ideas that we believe and those that we take to be fictitious by examining the process by which we come to the idea of each. A belief, according to Hume, is an idea that is accompanied by sentiment or feeling, and is not dependent on the will. A belief must be excited by nature and come from a specific situation in relation to the idea. By contrast, the imagination, which provides us with our fictitious ideas, can not attain the "vivid, forcible, firm, steady conception of an object" like a belief can.

Hume's Skeptical Doubts: The "sceptical doubts" that Hume has with regard to understanding are focused on the Objects of Reason or Inquiry called Matters of Fact. The problem with making an argument about the proposition the sun will rise tomorrow is that the negation is intelligible and is not a contradiction, unlike the Relations of Ideas, which have contradictory negations. Hume’s illustration of how an egg will taste is useful in defining sceptical doubt in relation to understanding. Each egg is, in appearance, similar to another. After periods of uniform experiments (eating eggs) one begins to have a certain reliance on the relation between the egg and how it will taste. The problem arises when Hume considers how we make the connection between our experience related to eggs and how we think the next egg will taste. Through what medium do we foresee "...that other objects, which are, in appearance, similar, will be attended with similar effects." The propositions of Matters of Fact do not seem come about through a chain of reasoning or through intuitive argumentation, because Matters of Fact are based on the relation of Cause and Effect, and the cause can never be determined from the effect. Rather, they come about through an inference based upon the supposition of the resemblance of things in the past to things in the future. The conclusion then becomes that, in terms of argument, Matters of Fact are probable only, and are open to doubt. Hume's Notion of Custom or Habit: Hume’s appeal to the notion of "Custom" or "Habit" is the explanation for how we infer that other similar objects will have the same effects as those before them.

"Hume", 2010, graphic drawing by Anthony Peter Iannini

Hume realizes that this does not explain the true nature of this process of experience and inference, "By employing the word [Custom], we pretend not to have given the ultimate reason of such a propensity" .

Despite this, the principle of Custom does illustrate a principle of human nature, and may be the farthest we can go in relation to the concept of experience and inference.

Hume’s conclusion then, is that all inferences from experience are arrived at not by reasoning, but by custom. All belief of Matters of Fact, then, come from some object and our memory (or sense) of another object that we gain through a customary conjunction.

This is clear because, if we did not proceed upon some fact that is present to the memory or senses, then we would have no foundation for our beliefs.

A lack of foundation (or a fact) in our beliefs would lead to infinitely argued reasons, or leave us with no reason in the first place. Again, Hume reinforces the notion that this is a principle of human nature, "All of these operations are a species of natural instincts which no reasoning or process of thought or understanding is able, either to produce, or to prevent."