David Hume was born April 26, 1711 in Edinburgh, Scotland. His father died the following year and left the estate to his eldest son, John. John ensured that David would receive a good Presbyterian upbringing and sent him -- at the age of 12 -- to the University of Edinburgh. David left three years later, to become a philosopher!

His family suggested he try law, and he tried, but found that it -- as he put it -- made him sick. So he went off to travel a few years in England and France. It was at a Jesuit College in France that he wrote A Treatise of Human Nature (in two parts), which he published anonymously in London in 1739.

Hume was the ultimate skeptic, convincingly reducing matter, mind, religion, and science to a matter of sense impressions and memories. First, he agreed with Bishop Berkeley that matter, or the existence of a world beyond our perceptions, is an unsupportable concept. Further, cause and effect were likewise unsupportable. We see sequences of events, but can never see the necessity that determinism requires. Further still, his investigations led him to dismiss the existence of a unifying mind within us. What we call mind is just a collection of mental perceptions. And finally, without mind, there can be no free will.

I will let him speak for himself. Pay close attention to some really good arguments!

All ideas are copies of impressions...it is impossible for us to think of anything which we have not antecedently felt by our senses....

When we entertain any suspicion in a philosophical term, we need but inquire from what impression is that supposed idea derived. If it be not possible to assign any, this will serve to confirm our suspicion that it is employed without meaning....

Some philosophers found much of their reasonings on the distinction of substance and quality. I would fain ask them whether the idea of substance be derived from impressions of sensations or impressions of reflection. Does it arise from an impression? Point it out to us, that we may know its nature and qualities. But if you cannot point out any such impression, you may be certain you are mistaken when you imagine you have any such idea.

The idea of substance is nothing but a collection of ideas of qualities, united by the imagination and given a particular name by which we are able to recall that collection. The particular qualities which form a substance are commonly referred to an unknown something in which they are supposed to "inhere." This is a fiction.

And so...no matter!

There are some philosophers (e.g. Berkeley) who imagine we are every moment intimately conscious of what we call our self; that we feel its existence and its continuance in existence, and are certain of its identity and simplicity.

For my part, when I enter most intimately into what I call my self, I always stumble on some particular perception or other, of heat or cold, light or shade, love or hatred, pain or pleasure, color or sound, etc. I never catch my self, distinct from some such perception.

I may venture to affirm of the rest of mankind that they are nothing but a bundle or collections of different perceptions which succeed each other with an inconceivable rapidity and are in a perpetual flux and movement. Our eyes cannot turn in their sockets without varying their perceptions. Our thoughts are still more variable. And all our other senses and powers contribute to this change.

The mind (or self) is a kind of theatre where perceptions make their appearances, pass, repass, glide away, and mingle in an infinite variety. But there is no simplicity, no one simple thing present or pervading this multiplicity; no identity pervading this process of change; whatever natural inclination we may have to imagine that there is. The comparison of the theatre must not mislead us: it persists, while the actors come and go. Whereas, only the successive perceptions consititute the mind.

As memory alone acquaints us with the continuance and extent of a succession of perceptions, it is to be considered, on that account chiefly, as the source of personal identity. Had we no memory, we should never have any notion of that succession of perceptions which constitutes our self or person. But having once acquired this notion from the operation of memory, we can extend the same beyond our memory and come to include times which we have entirely forgot. And so arises the fiction of person and personal identity.

And no mind!

There is no idea in metaphysics more obscure or uncertain than necessary connection between cause and effect. We shall try to fix the precise meaning of this term by producing the impression from which it is copied. When we look at external objects, and consider the operation of causes, we are never able, in a single instance, to discover a necessary connection; any quality which binds the effect to the cause, and renders one a necessary consequence of the other. We find only that the effect does, in fact, follow the cause. The impact of one billiard ball upon another is followed by the motion of the second. There is here contiguity in space and time, but nothing to suggest necessary connection.

Why do we imagine a necessary connection? From observing many constant conjunctions? But what is there in a number of instances which is absent from a single instance? Only this: After a repetition of similar instances the mind is carried by habit, upon the appearance of the cause, to expect the effect. This connection, which we feel in the mind, this customary and habitual transition of the imagination from a cause to its effect, is the impression from which we form the idea of necessary connection. There is nothing further in the case.

Out with cause and effect!

The most irregular and unexpected resolutions of men may be accounted for by those who know every particular circumstance of their character and situation. A genial person, contrary to expectation, may give a peevish answer, but he has a toothache or has not dined. Even when, as sometimes happens, an action cannot be accounted for, do we not put it down to our ignorance of relevant details?

Thus it appears that the conjunction between motive and action is as regular and uniform as between cause and effect in any part of nature. In both cases, constant conjunction and inference from one to the other.

Free will is only our ignorance of cause and effect, and cause and effect is an illusion, so free will is an illusion. Simple.

In all reasonings from experience, then, there is a step taken by the mind (that the future resembles the past) which is not supported by any argument. Nevertheless, we take this step. There must therefore be some other principle (than rational or demonstrative argument). This principle is custom....

What, then, is the conclusion of the whole matter? A simple one, though, it must be confessed, pretty remote from the common theories of philosophy. All belief concerning matters of fact or real existence, is derived merely from some object present to the memory or the senses, and a customary conjunction between that and some other object. Having found, in many instances, that two kinds of objects have been conjoined (say, flame and heat), the mind is carried by custom to expect the same in the future. This is the whole operation of the mind in all our conclusions concerning matters of fact and existence.

So long, science!

If we take in hand any volume, of divinity or metaphysics, for instance, let us ask: Does it contain any reasoning concerning quantity or number? No. Does it contain any experimental (probable) reasoning concerning matter of fact? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion.

I am at first affrighted and confounded with that forlorn solitude in which I am placed by my philosophy, and fancy myself some strange uncouth monster, utterly abandoned and disconsolate. Fain would I run into the crowd for shelter and warmth. I call upon others to join me. But no one will hearken to me. Everyone keeps at a distance, and dreads that storm which beats upon me from every side. I have exposed myself to the emnity of all metaphysicians, logicians, mathematicians, and theologians. Can I wonder at the insults I must suffer? I have declared my disapprobation of their systems. Can I be surprised if they should express a hatred of my ideas and my person? When I look about me, I foresee on every hand, dispute, contradiction, anger, calumny, detraction. When I turn my eye inward, I find only doubt and ignorance. Every step I take is with hesitation; every new reflection makes me dread an error and absurdity in my reasoning.

In 1739, he returned to Edinburgh, where he added a third part to A Treatise, on morality. He suggested that morality comes from sympathy, which is an instinct for association with others. He goes on to say that it is emotions that move us, not reason, and he presages Jeremy Bentham’s utilitarianism by defining virtue as “every quality of the mind which is useful or agreeable to the person himself or others.” Even beauty is based on pleasure and pain, and love is based on our desire to reproduce -- shades of Freud!. What little attention this part received was negative.

At this point in his life, he went through several minor political positions. And he gained a great deal of weight -- something unusual among philosophers! Then, in 1748, he published An Enquiry Concerning the Human Understanding, followed in 1751 by An Enquiry Concerning the Principles of Morals. These were essentially a rewrite of A Treatise. In it, he included a new essay, “Of Miracles,” wherein he portrays some of Christianity’s most basic beliefs as nothing but superstition!

He continued on that subject with Dialogues Concerning Natural Religion, in which he compared Christianity, Deism, and Atheism. Among other things, he suggests that the world we know -- including ourselves -- is the result of eons of nature’s experiments. His friends asked him not to publish it. They published it for him posthumously (no pun intended).

In 1752, he wrote Political Discourses. Although he liked egalitarianism (roughly, communism) and democracy, he felt that both were too idealistic. This book influenced Adam Smith, the father of modern capitalism.

In 1754, he published the first volume of the History of England, a book admired by such notables as Voltaire and Gibbon (the author of The Decline and Fall of the Roman Empire).

In 1763 he went to Paris, where he soon became the talk of the town and was especially popular at the salons of the great aristocratic women of France, who apparently took a liking to his grand body as well as his great mind. Several years later, he brought the nearly insane Rousseau to England, which turned out to be a disagreeable adventure for both of them.

He died August 25, 1776, of ulcerative colitis. His friends found the great atheist polite, pleasant, even cheerful, to the end.