David Hume

David Hume

Era	18th-century philosophy
Region	Western Philosophy
School	Naturalism, Scepticism, Empiricism, Scottish Enlightenment
Main interests	Epistemology, Metaphysics, Philosophy of Mind, Ethics, Political Philosophy, Aesthetics, Philosophy of Religion
Notable ideas	Problem of causation, Induction, Is-ought problem
Influenced by Locke, Berkeley, Thomas Hobbes, Hutcheson, Newton, Epicurus, Cicero, Malebranche
Influenced Adam Smith, Adam Ferguson, Immanuel Kant, Jeremy Bentham, James Madison, Alexander Hamilton, Arthur Schopenhauer, Auguste Comte, John Stuart Mill, Baron d'Holbach, Darwin, Thomas Huxley, William James, Bertrand Russell, Einstein, Karl Popper, Alfred Ayer, J. L. Mackie, Noam Chomsky, Simon Blackburn, Iain King

David Hume ( April 26, 1711– August 25, 1776), Scottish philosopher, economist, and historian is an important figure in Western philosophy, and in the history of the Scottish Enlightenment.

He first gained recognition and respect as a historian; but interest in Hume's work in academia has in recent years centered on his philosophical writing. His History of England was the standard work on English history for many years, until Macaulay's The History of England from the Accession of James the Second.

Hume was the first great philosopher of the modern era to carve out a thoroughly naturalistic philosophy. This philosophy partly consisted in rejection of the historically prevalent conception of human minds as being miniature versions of the divine mind. This doctrine was associated with a trust in the powers of human reason and insight into reality, which possessed God’s certification. Hume’s scepticism came in his rejection of this ‘insight ideal’, and the (usually rationalistic) confidence derived from it that the world is as we represent it. Instead, the best we can do is to apply the strongest explanatory and empirical principles available to the investigation of human mental phenomena, issuing in a quasi-Newtonian project, Hume's ‘Science of Man’.

Hume was heavily influenced by empiricists John Locke and George Berkeley, along with various French-speaking writers such as Pierre Bayle, and various figures on the English-speaking intellectual landscape such as Isaac Newton, Samuel Clarke, Francis Hutcheson, Adam Smith, and Joseph Butler.

Life

David Home, son of Joseph Home of Chirnside, advocate, and Katherine Lady Falconer, was born on 26 April 1711 ( Old Style) in a tenement on the north side of the Lawnmarket in Edinburgh. He changed his name to Hume in 1734 because the English had difficulty pronouncing 'Home' in the Scottish manner. Throughout his life Hume, who never married, spent time occasionally at his family home at Ninewells by Chirnside, Berwickshire.

Education

Hume's family sent him to the University of Edinburgh at the unusually early age of twelve (possibly as young as ten) at a time when fourteen was normal. At first he considered a career in law, but came to have, in his words, "an insurmountable aversion to everything but the pursuits of Philosophy and general Learning; and while [my family] fanceyed I was poring over Voet and Vinnius, Cicero and Vergil were the Authors which I was secretly devouring." He had little respect for professors, telling a friend in 1735, "there is nothing to be learned from a Professor, which is not to be met with in Books."

At the age of eighteen, Hume made a philosophical discovery that opened up to him "a new Scene of Thought," which inspired him "to throw up every other Pleasure or Business to apply entirely to it". He did not recount what this "Scene" was, and commentators have offered a variety of speculations. Due to this inspiration, Hume set out to spend a minimum of ten years reading and writing. He came on the verge of nervous breakdown, after which he decided to have a more active life to better continue his learning.

Career

As Hume's options lay between a traveling tutorship and a stool in a merchant's office, he chose the latter. In 1734, after a few months in commerce in Bristol, he went to La Flèche in Anjou, France. He had frequent discourses with the Jesuits of the famous college where Descartes was educated. As he spent most of his savings during his four years there while writing A Treatise of Human Nature, he resolved "to make a very rigid frugality supply my deficiency of fortune, to maintain unimpaired my independency, and to regard every object as contemptible except the improvements of my talents in literature." He completed the Treatise at the age of twenty-six.

Although many scholars today consider the Treatise to be Hume's most important work and one of the most important books in western philosophy, the critics in Great Britain at the time did not agree, describing it as "abstract and unintelligible". Despite the disappointment, Hume later wrote, "Being naturally of a cheerful and sanguine temper, I soon recovered from the blow and prosecuted with great ardour my studies in the country". There, he wrote the Abstract. Without revealing his authorship, he aimed to make his larger work more intelligible by shortening it.

After the publication of Essays Moral and Political in 1744, Hume applied for the Chair of Pneumatics and Moral Philosophy at the University of Edinburgh. However, the position was given to William Cleghorn, after Edinburgh ministers petitioned the town council not to appoint Hume due to his atheism.

During the 1745 Jacobite Rebellion, Hume tutored the Marquise of Annandale (1720-92), who was officially described as a "lunatic". This engagement ended in disarray after about a year. But it was then that Hume started his great historical work The History of Great Britain, which would take fifteen years and run to over a million words, to be published in six volumes in the period between 1754 and 1762. During this period, he was involved with the Canongate Theatre. In this context, he associated with Lord Monboddo and other Scottish Enlightenment luminaries in Edinburgh. From 1746, Hume served for three years as Secretary to Lieutenant-General St Clair, and wrote Philosophical Essays Concerning Human Understanding, later published as An Enquiry Concerning Human Understanding. The Enquiry proved little more successful than the Treatise.

Hume was charged with heresy, but he was defended by his young clerical friends, who argued that—as an atheist—he was outside the Church's jurisdiction. Despite his acquittal—and possibly due to the opposition of Thomas Reid of Aberdeen, who that year launched a Christian critique of his metaphysics—Hume failed to gain the Chair of Philosophy at the University of Glasgow.

It was after returning to Edinburgh in 1752, as he wrote in My Own Life, that "the Faculty of Advocates chose me their Librarian, an office from which I received little or no emolument, but which gave me the command of a large library." This resource enabled him to continue historical research for The History of Great Britain.

Hume achieved great literary fame as a historian. His enormous The History of Great Britain, tracing events from the Saxon kingdoms to the Glorious Revolution, was a best-seller in its day. In it, Hume presented political man as a creature of habit, with a disposition to submit quietly to established government unless confronted by uncertain circumstances. In his view, only religious difference could deflect men from their everyday lives to think about political matters.

However, Hume's volume of Political Discourses (1752) was the only work he considered successful on first publication.

Religion

Hume's early essay Of Superstition and Religion laid the foundations for nearly all subsequent secular thinking about the history of religion. Critics of religion during Hume's time had to express themselves cautiously. Less than 15 years before Hume's birth, an 18-year-old University student named Thomas Aikenhead was tried, convicted, and hanged for blasphemy for saying Christianity was nonsense. Hume followed the common practice of expressing his views obliquely, through characters in dialogues. He did not acknowledge authorship of Treatise until the year of his death, in 1776.

Hume's essays On Suicide, On the Immortality of the Soul, and Dialogues concerning Natural Religion were not published until after his death, and even then bore neither author's nor publisher's name. Hume's atheism caused him to be passed over for many positions.

Hume told his friend, Mure of Caldwell, of an incident that occasioned his "conversion" to Christianity. Passing across the recently drained Nor’ Loch to the New Town of Edinburgh to supervise the masons building his new house, soon to become No. 1 St. David Street, he slipped and fell into the mire. Hume, being then of great bulk, could not regain his feet. Some passing Newhaven fishwives saw his plight but recognised him as the well-known atheist, and refused to rescue him unless he became a Christian and recited The Lord’s Prayer and the Creed. This he did, and was rewarded by being set again on his feet by these brawny women. Hume asserted thereafter that Edinburgh fishwives were the "most acute theologians he had ever met".

Later life

From 1763 to 1765, Hume was Secretary to Lord Hertford in Paris, where he was admired by Voltaire and lionised by the ladies in society. He made friends, and later fell out, with Jean-Jacques Rousseau. He wrote of his Paris life, "I really wish often for the plain roughness of The Poker Club of Edinburgh . . . to correct and qualify so much lusciousness." For a year from 1767, Hume held the appointment of Under Secretary of State for the Northern Department. In 1768, he settled in Edinburgh.

James Boswell visited Hume a few weeks before his death. Hume told him he sincerely believed it a "most unreasonable fancy" that there might be life after death. This meeting was dramatized in semi-fictional form for the BBC by Michael Ignatieff as Dialogue in the Dark. Hume wrote his own epitaph: "Born 1711, Died [----]. Leaving it to posterity to add the rest." It is engraved with the year of his death 1776 on the "simple Roman tomb" he prescribed, and which stands, as he wished it, on the Eastern slope of the Calton Hill overlooking his home in the New Town of Edinburgh at No. 1 St. David Street.

Science of Man

In the introduction to A Treatise of Human Nature, Hume writes “the science of man is the only solid foundation for the other sciences”, and that the correct method for this science is “experience and observation”; i.e. the empirical method.

However, scholars have disagreed on the precise form of Hume’s enterprise and, in particular, what sort of empiricism he favoured. The Logical Positivists took Hume’s project to be one of analysing sentences to find out the empirical conditions that make those sentences meaningful. According to the Logical Positivists, unless a statement could be verified or falsified by experience, or else was true or false by definition (i.e. either tautological or contradictory), then it was meaningless (this is their famous Verification Principle). Hume, on this view, was a proto-Positivist, who, in his philosophical writings, took to showing how ordinary sentences about objects, causal relations, the self, etc., were semantically equivalent to sentences about one’s experiences.

However, not all critics agree with Logical Positivist interpretation. A standard argument against it is that, whereas the Logical Positivists took the Verification Principle to lead to anti-Sceptical conclusions, Hume described himself as a mitigated Sceptic. Instead it has been argued that, rather than exploring the experiential conditions of the meaningfulness of sentences, Hume was giving an account of conditions under which we come to form certain ideas and beliefs; that is to say, he was giving a causal account of the origin of general concepts of the external world, causation, the self, and so on. On this view, our forming and using such concepts is the result of an in-built, natural disposition to deploy faculties of the mind such as custom, habit, and the imagination. Another way of expressing this is to say that he was not concerned with advancing a theory of semantics — i.e. what we mean when we talk about, say, physical objects or causal relations — but rather was carrying out an epistemological enquiry, asking in effect how the stimuli of the senses and our conceptual apparatus work together to compel us to form various sorts of judgements and to make claims to knowledge.

What follows explores central philosophical concepts that Hume wrote about, and different interpretations of his arguments.

Causation

Hume’s views on the concept of causation are much disputed. There are at least three different interpretations represented in the literature. These are:

(i) The Logical Positivist interpretation
(ii) The Sceptical Realist interpretation
(iii) The Quasi-Realist and Projectivist interpretation

According to the positivist view, Hume is attempting to specify the semantic content of the concept of causation — i.e. what we mean when we deploy causal terms. The traditional analytical take on Hume’s answer is that it is to be found in the regular succession of certain of our impressions; their ‘constant conjunction’. On this interpretation, Hume is saying that statements such as "A caused B" are equivalent to propositions such as "Whenever A occurs, then B does", where "whenever" refers to all possible observations of A and B.

This has been rejected, however, by Sceptical Realists, who argue that Hume was not discussing the meaning of causal terms, but rather their source, or their causal origin, in our experience. The major disagreement with the Positivist view is over Hume’s take on the idea of Necessary Connexion. According to the Positivists, as we have seen, causality consists only in regularities in perceptions, but the Sceptical Realists point out that Hume also thought there to be a Necessary Connexion between causes and effects that goes unperceived. The reason Hume is called a Sceptical Realist on this take is that he did not think we could have perceptual access to the necessary connexion, and thus we have no reason to believe in it (hence Scepticism); but at the same time we are compelled by natural instinct to believe there to be a necessary connexion when we observe a regularity or constancy in our perceptions, and this natural belief is of an external causal necessity (hence Realism).

However, the Sceptical Realist reading has been rejected by Simon Blackburn, who instead proposes a Projectivist and Quasi-Realist interpretation. According to this position, Hume was not arguing that we have a concept of a Real necessary connexion, where "Real" means that our idea represents something in the world, external to human minds. Instead, our concept of causation is composed of two elements (corresponding to Hume's two famous "definitions" of causation), the first is the regular succession given in perception, but the second—the necessary connexion—is actually a product of a functional change in the human mind that allows us to anticipate and predict future events based on past regularities. So, the Quasi-Realist denies that the necessary connexion is a property existing in the world (hence he denies straightforward Realism), and instead sees it as representative of a change in our mental states and practical attitudes. However, this does not amount to a full-on Anti-Realism about Causation, because the Quasi-Realist is also a Projectivist, who holds that it is perfectly legitimate to "project" our predictions by making statements that express the belief in a necessary connexion. It is not that we talk "as-if" there were a necessary connexion, when really there is not: rather, our talk of there being a necessary connexion is a way of voicing a distinctive mental set, which allows us to explain and predict the behaviour of objects, and hopefully come to control them too. Thus, when Hume says that “nothing is more usual than to apply to external bodies every internal sensation which they occasion”, he is not diagnosing an error in human thought, but merely giving a scientific explanation of how our concepts arise.

Problem of induction

The Problem of Induction has received a great deal of critical attention. Though Hume offered his own solution, many have since questioned whether he was successful. As a result, many modern commentators have attempted their own solutions. This section will explore some of these.

Inductive inference is the ability to infer from past regularities—e.g., from the fact that B has always followed A—to future and presently unobserved instances of that regularity—e.g., that if A occurs, B will follow. For example, the fact that fire has always burned us in the past leads us to believe that fire will continue to burn us in the future, and that if any person is currently touching fire, it is burning them. The problem of induction is the problem of explaining this ability: how can we know the way things will behave when they go "beyond the present testimony of the senses, and the records of our memory"?

Hume argues that induction is founded on the persistence of regularities (sometimes called the Uniformity of Nature) and that we cannot know nature is uniform through reason, because reason only comes in two sorts, and both of these are inadequate. The two sorts are:

(i) Demonstrative reasoning (effectively, deductive reasoning)
(ii) Probable reasoning (effectively, inductive reasoning)

With regard to (i), Hume argues that we cannot prove a priori that regularities will continue, as it is "consistent and conceivable" that the course of nature might change. Coming to (ii), Hume argues that founding a regularity on the fact that regularity has always operated in the past (inductive reasoning) is arguing in a circle, because induction was the very process we were trying to explain in the first place. Hence no form of reason will sponsor inductive inference.

This argument has been criticised in more than one area. For example, some have maintained that Kantian arguments can establish that nature is uniform. Some counter, however, that even if Kantian arguments can prove a priori that nature is uniform in general, this does not make inductive inference rational, because there is still the problem of working out which particular regularities will continue.

A further criticism is that there are more types of reasoning than Hume allows (the two types of demonstrative and probabilistic), for one can give deductive reasons for probability distributions, and it might be that a demonstration of the high probability of success of an inductive policy can succeed in showing induction to be rational. However, it could be argued that Nelson Goodman showed that no purely formal treatment can work. Goodman identified certain regularities that cannot be successfully 'projected' into the future: for example, if we define a new predicate " grue", such that something is grue if it is green until the year 3000, and blue thereafter, we know that all emeralds thus far have been "grue", but we do not assume they will continue to be grue after 3000 AD, because that would be to assume they will turn blue at a random point in time. Thus, a non-formal distinction must be made between those predicates that can, and those that can't, be projected: Simon Blackburn, for example, argued that the distinction is between observational predicates and non-observational predicates. This seems to counter the idea that purely formal a priori probabilistic reasoning can show induction to be rational.

Solutions to the Problem

Turning from Hume's problem, we will exhibit different solutions that have been given to the problem. There are three main categories of contemporary response to the problem, as follows:

(i) The Analytic Solution
(ii) The Inductive Solution
(iii) The Pragmatic Solution

The first analytic solution was argued for by P. F. Strawson. Essentially, it contends that the question of whether induction is rational is nonsense, as when we say something is rational, we just mean it is inductive (or deductive). That is, any inductive inference is a ‘rational’ inference, because inductive inferences are the sort of things we take as defining the concept of ‘reason’, or ‘rational’ argumentation: “to call a particular belief reasonable or unreasonable is to apply inductive standards”. The question, “is induction rational?” is, says Strawson, akin to the question, “is the law legal?” That is to say, induction is analytically a rational policy: to ask after its rationality is to misunderstand the definition of the concept.

However, the analytic solution has been opposed on the grounds that the question now transfers to one of whether we should prefer to be 'rational' as defined. Brian Skyrms imagines a tribe who use a Shaman to make their predictions about the future, and calls this method 'brational'. The question is now, why should we prefer 'rationality' to 'brationality'?

A possible answer might be found in the inductive solution, proposed by Max Black. It might be thought that, as Hume argued, we cannot use induction to legitimate induction, for that would be circular. But Black argues that our justification of induction is a second-order appeal to the success not of individual predictions, but to rules of prediction. The question comes, what justifies the use of the rules of induction? Again, Black maintains, we must appeal to our past success. Furthermore, (and pre-empting anymore aimless probing), this third level of justification is justified by its past success, and so on, ad infinitum.

Skyrms has, again, argued against this. He asserts that we can imagine an Anti-Inductive policy that is just as justifiable as the Inductive one, according to Black's defence. An anti-inductive argument goes something like this: the sun has always risen in the past, therefore it will not rise tomorrow. When we ask what justifies making such an inference, the anti-inductivist appeals to a second-order anti-inductive rule: “Well, anti-inductive arguments have never worked in the past; therefore they will work this time”. If the anti-inductivist is pushed, he will respond in a like manner again and again: “The rules of anti-inductive arguments have never worked for me before, so they are sure to work this time”. Essentially the anti-inductivist is able to generate precisely the same chain of ‘justification’ as the inductivist, and there is no way now of choosing between an inductive and an anti-inductive policy: they are equally ‘justified’. Skyrms takes this as a reductio of Black's proposed solution.

The pragmatist hopes to justify induction by appeal to its tendency to be right if any policy will, because induction can factor in the successes of other predictive policies. However, some argue that the fact that an inductive policy of prediction is as successful as, or more successful than any other does not show which particular regularities will persist, and this is what we need if we are to explain our ability to project the right regularities.

Turning from contemporary attempts to justify induction, we can look at Hume's own response to the problem. Hume argued in effect that although Reason cannot explain our ability to make correct inductive inference, natural instinct can. Hume says that "Nature, by an absolute and uncountroulable necessity has determin'd us to judge as well as to breathe and feel". Some modern commentators agree with Hume's solution; for example, Oxford Professor John Kenyon, who has argued: "Reason might manage to raise a doubt about the truth of a conclusion of natural inductive inference just for a moment in the study, but the forces of nature will soon overcome that artificial scepticism, and the sheer agreeableness of animal faith will protect us from excessive caution and sterile suspension of belief."

The self: bundles and beliefs

There are at least two broadly different ways of interpreting Hume’s views on personal identity. According to the first view, Hume was a bundle theorist, who held that the self is nothing but a bundle of interconnected perceptions. This view is forwarded by, for example, Positivist interpreters, who saw Hume as attempting to specify the “sense-contents” (roughly, bits of sensory-experience) that we refer to when we talk about the self. This account draws on Hume’s remarks that a person is “a bundle or collection of different perceptions”. A modern day version of the bundle theory of the mind has been advanced by Derek Parfit.

However, some have criticised the bundle theory interpretation of Hume on personal identity. Some account for Hume’s talk of people being bundles of perceptions as figurative, and raise the problem for such a view (at least in its basic form) that it is difficult to specify what it is that makes a bundle of perceptions the perceptions of a distinct person; for it seems that we can have similar perceptions to one another, and that the interconnections between our own perceptions (such as causal connections) can be shared with others’ perceptual states too.

An alternative theory is that Hume is answering an epistemological question about the cause of people forming judgements or beliefs about the existence of the self. In support of this interpretation we can point to passages that use causal terminology: “What then gives us so great a propension to ascribe an identity to these successive perceptions, and to suppose ourselves possest of an invariable and uninterrupted existence thro' the whole course of our lives?”

This reading of Hume sets out the problem that, although experience is interrupted and ever-changing, we somehow form a concept of a constant self that is the subject of these experiences. Hume’s answer on this account is that it is the same interconnections and relations between perceptions that force the imagination to believe in the existence of mind-independent objects. In effect, Hume argues that we cannot make sense of the notion of objects existing independently of ourselves unless we have an idea of 'ourself' as something that occasionally becomes aware of these objects. The human mind, or consciousness, is thus conceived of as a field of experience, into which various different objects appear and then disappear: "the true idea of the human mind, is to consider it as a system of different perceptions or different existences, which are link'd together by the relation of cause and effect, and mutually produce, destroy, influence, and modify each other."

Practical reason

Hume's most famous sentence occurs at Treatise, II, III, iii, Of the influencing motives of the will: "Reason is, and ought only to be, the slave of the passions, and can never pretend to any other office than to serve and obey them." Hume here extends his anti-rationalism from the epistemological sphere into that of the theory of action, and demonstrates that the faculty of reason cannot, of itself, move the will. He starts the section by going over the by now familiar distinction between demonstrative and probable reasoning (roughly, deductive and inductive reasoning). He then argues that neither can influence the will, as both simply provide information — deductive reasoning about correct mathematical or logical inference and inductive reasoning about causal connections — and it is always open to us as to how to act on this information. Hume then argues that to be moved to act on the information provided us by reason, passions, desires and inclinations must play a role. To take a simple example: using causal reasoning I can discern that if I drink a lot of wine, I will get drunk, but the truth of this conditional will not motivate me to do anything unless I have some desire, in this case the desire to be drunk. As such, Hume forwards the basic folk psychological action-theory that a motive to action requires both a belief (ascertained by the understanding) and a desire (provided by the passions). This theory is still hotly contested, with Humean philosophers such as Simon Blackburn and Michael Smith on one side, and moral cognitivists, like John McDowell, and Kantians, like Christine Korsgaard, on the other.

Sentiment-based ethical theory

Hume first discusses ethics in A Treatise of Human Nature. He later extracts and expounds upon the ideas he proposed in Treatise in a shorter essay entitled An Enquiry Concerning the Principles of Morals. Hume's approach in Enquiry is fundamentally an empirical one. Instead of telling us how morality ought to operate, he tells us how we actually make moral judgments. After providing us with various examples, he comes to the conclusion that most, though not all, of the behaviors we approve of increase public utility. He supposes that humans may be, in the language of today, 'hard-wired' to approve of things that help society– public utility. Hume used this insight to explain how we evaluate a wide array of phenomena, ranging from social institutions and government policies to character traits and talents.

Nonetheless, Hume is no utilitarian. In line with his debunking of religion, and of knowledge itself, he has no time for theories attempting to put ethics on a pedestal. But nor is he entirely contemptuous of public morality. Unlike Thomas Hobbes, Hume considers the ethical impulse a worthy one, based on more than self-interest. This is because, in addition to considerations of self-interest, Hume maintains that we can be moved by our 'sympathy' for others, fundamental human impulses that provide a person with thoroughly non-selfish concerns and motivations—sometimes referred to by contemporary theorists as altruistic concern.

Here, Hume follows his close friend and (at the time) much more highly respected contemporary, Adam Smith whose book entitled 'The Theory of the Moral Sentiments' (1759) starts with a chapter entitled 'Of Sympathy'. Smith's theory was intended to explain the operations of human society in much the same way as his (better-remembered) economic works on the nature of money. The theory assumes that there are, in fact, "no differences between right and wrong, just different emotional responses to acts" as Martin Cohen has put it. This is why Hume says: "It is not contrary to reason to prefer the destruction of the whole world to the scratching of my finger" Instead, Hume defends his sympathy-based, moral sentimentalism by claiming that we could never make moral judgments based on reason alone. Our reason deals with facts and draws conclusions from them, but, Ceteris paribus, it could not lead us to choose one option over the other; only our sentiments can do this. Also, our sympathy-based sentiments can motivate us towards the pursuit of non-selfish ends, like the utility of others. For Hume, and for fellow sympathy-theorist Adam Smith, the term "sympathy" is meant to capture much more than concern for the suffering of others. Sympathy, for Hume, is a principle for the communication and sharing of sentiments, both positive and negative. In this sense, it is akin to what contemporary psychologists and philosophers call empathy. In developing this sympathy-based moral sentimentalism, Hume surpasses the divinely implanted moral sense theory of his predecessor, Francis Hutcheson, by elaborating a naturalistic, moral psychological basis for the moral sense, in terms of the operation of sympathy. Hume's arguments against founding morality on reason are often now included in the arsenal of moral anti-realist arguments. As Humean-inspired philosopher John Mackie suggests, for there to exist moral facts about the world, recognizable by reason and intrinsically motivating, they would have to be very queer facts. Still, there is considerable debate among scholars as to Hume's status as a realist versus anti-realist.

Free will and responsibility

Hume advocated a moral theory based on the freedom of the human will and its relation to the individual's character. Hume believed that effects follow necessarily from their causes, and that this principle of determinism applies equally to people and their actions. In addition, Hume held that a person enjoyed free will, or what he often termed liberty, as long as their will wasn't constrained (for example a person would not be at liberty to give charity if they are locked up in a cell). Given such definitions of determinism and free will, Hume wrote that the two concepts are compatible, a theory known as compatibilism.

In opposition to Christian thinkers (e.g., Samuel Clarke) who argued that for a person to be morally responsible, his actions must not be determined by any physical cause, Hume wrote that moral responsibility requires determinism: Hume argued that if effects are not determined by their causes then they're random, and similarly if actions aren't caused by the character then they're random and not the responsibility of the person who committed them.

Beyond saying that a person is only responsible when they enjoy free will, and that free will is when one gets to act according to one's character, Hume also offers a psychological evaluation of why we judge people. Hume says that we hold people to blame or approbation when we judge their character as being respectively harmful or beneficial to society. Following from Hume's ideas on experience and causation, this means that when, for example, we experience a person's character (the cause) as resulting in a bad action (the effect), we apply the principle that similar causes result in similar effects, judge that the character will result in future bad actions, and decide that it is important to blame that person for the good of the society.

The is-ought problem

Hume noted that many writers talk about what ought to be on the basis of statements about what is ( is-ought problem). But there seems to be a big difference between descriptive statements (what is) and prescriptive statements (what ought to be). Hume calls for writers to be on their guard against changing the subject in this way without giving an explanation of how the ought-statements are supposed to follow from the is-statements. But how exactly can you derive an "ought" from an "is"? That question, prompted by Hume's small paragraph, has become one of the central questions of ethical theory, and Hume is usually assigned the position that such a derivation is impossible. (Others interpret Hume as saying not that one cannot go from a factual statement to an ethical statement, but that one cannot do so without going through human nature, that is, without paying attention to human sentiments.) Hume is probably one of the first writers to make the distinction between normative (what ought to be) and positive (what is) statements, which is so prevalent in social science and moral philosophy. G. E. Moore defended a similar position with his "open question argument", intending to refute any identification of moral properties with natural properties (" naturalistic fallacy").

Murray N. Rothbard contends that Hume in fact failed to prove that values cannot be derived from facts. Some allege that nothing can be in the conclusion of an argument that was not in one of the premises; and that therefore, an "ought" conclusion cannot follow from descriptive premises. But a conclusion follows from both premises taken together; the "ought" need not be present in either one of the premises so long as it has been validly deduced. To say that it cannot be so deduced simply begs the question.

The problem of miracles

In his discussion of miracles in An Enquiry concerning Human Understanding (Section 10) Hume defines a miracle as "a transgression of a law of nature by a particular volition of the Deity, or by the interposition of some invisible agent". Given that Hume argues that it is impossible to deduce the existence of a Deity from the existence of the world (for he says that causes cannot be determined from effects), miracles (including prophesy) are the only possible support he would conceivably allow for theistic religions.

Hume discusses everyday belief as often resulted from probability, where we believe an event that has occurred most often as being most likely, but that we also subtract the weighting of the less common event from that of the more common event. In the context of miracles, this means that a miraculous event should be labeled a miracle only where it would be even more unbelievable (by principles of probability) for it not to be. Hume mostly discusses miracles as testimony, of which he writes that when a person reports a marvelous event we (need to) balance our belief in their veracity against our belief that such events do not occur. Following this rule, only where it is considered, as a result of experience, less likely that the testimony is false than that a miracle occur should be believe in miracles.

Although Hume leaves open the possibility for miracles to occur and be reported, he offers various arguments against this ever having happened in history:

• People often lie, and they have good reasons to lie about miracles occurring either because they believe they are doing so for the benefit of their religion or because of the fame that results.
• People by nature enjoy relating miracles they have heard without caring for their veracity and thus miracles are easily transmitted even where false.
• Hume notes that miracles seem to occur mostly in "ignorant" and "barbarous" nations and times, and the reason they don't occur in the "civilized" societies is such societies aren't awed by what they know to be natural events.
• The miracles of each religion argue against all other religions and their miracles, and so even if a proportion of all reported miracles across the world fit Hume's requirement for belief, the miracles of each religion make the other less likely.

Despite all this Hume observes that belief in miracles is popular, and that "The gazing populace receive greedily, without examination, whatever soothes superstition and promotes wonder."

Critics have argued that Hume's position assumes the character of miracles and natural laws prior to any specific examination of miracle claims, and thus it amounts to a subtle form of begging the question. They have also noted that it requires an appeal to inductive inference, as none have observed every part of nature or examined every possible miracle claim (e.g., those yet future to the observer), which in Hume's philosophy was especially problematic (see above).

The design argument

One of the oldest and most popular arguments for the existence of God is the design argument– that all the order and 'purpose' in the world bespeaks a divine origin. A modern manifestation of this belief is creationism. Hume gave the classic criticism of the design argument in Dialogues concerning Natural Religion and An Enquiry concerning Human Understanding. Here are some of his points:

1. For the design argument to be feasible, it must be true that order and purpose are observed only when they result from design. But order is observed regularly, resulting from presumably mindless processes like snowflake or crystal generation. Design accounts for only a tiny part of our experience with order and "purpose".
2. Furthermore, the design argument is based on an incomplete analogy: because of our experience with objects, we can recognise human-designed ones, comparing for example a pile of stones and a brick wall. But to point to a designed Universe, we would need to have an experience of a range of different universes. As we only experience one, the analogy cannot be applied. We must ask therefore if it is right to compare the world to a machine — as in Paley's watchmaker argument — when perhaps it would be better described as a giant inert animal.
3. Even if the design argument is completely successful, it could not (in and of itself) establish a robust theism; one could easily reach the conclusion that the universe's configuration is the result of some morally ambiguous, possibly unintelligent agent or agents whose method bears only a remote similarity to human design. In this way it could be asked if the designer was God, or further still, who designed the designer?
4. If a well-ordered natural world requires a special designer, then God's mind (being so well-ordered) also requires a special designer. And then this designer would likewise need a designer, and so on ad infinitum. We could respond by resting content with an inexplicably self-ordered divine mind but then why not rest content with an inexplicably self-ordered natural world?
5. Often, what appears to be purpose, where it looks like object X has feature F in order to secure outcome O, is better explained by a filtering process: that is, object X wouldn't be around did it not possess feature F, and outcome O is only interesting to us as a human projection of goals onto nature. This mechanical explanation of teleology anticipated natural selection. (see also Anthropic principle)
6. The design argument does not explain pain, suffering, and natural disasters.

Political theory

Many regard David Hume as a political conservative, sometimes calling him the first conservative philosopher. This is not strictly accurate, if the term conservative is understood in any modern sense. His thought contains elements that are, in modern terms, both conservative and liberal, as well as ones that are both contractarian and utilitarian, though these terms are all anachronistic. His central concern is to show the importance of the rule of law, and stresses throughout his political Essays the importance of moderation in politics. This outlook needs to be seen within the historical context of eighteenth century Scotland, where the legacy of religious civil war, combined with the relatively recent memory of the 1715 and 1748 Jacobite risings, fostered in a historian such as Hume a distaste for enthusiasm and factionalism that appeared to threaten the fragile and nascent political and social stability of a country that was deeply politically and religiously divided. He thinks that society is best governed by a general and impartial system of laws, based principally on the "artifice" of contract; he is less concerned about the form of government that administers these laws, so long as it does so fairly (though he thought that republics were more likely to do so than monarchies).

Hume expressed suspicion of attempts to reform society in ways that departed from long-established custom, and he counselled people not to resist their governments except in cases of the most egregious tyranny. However, he resisted aligning himself with either of Britain's two political parties, the Whigs and the Tories, and he believed that we should try to balance our demands for liberty with the need for strong authority, without sacrificing either. He supported liberty of the press, and was sympathetic to democracy, when suitably constrained. It has been argued that he was a major inspiration for James Madison's writings, and the Federalist No. 10 in particular. He was also, in general, an optimist about social progress, believing that, thanks to the economic development that comes with the expansion of trade, societies progress from a state of "barbarism" to one of "civilisation". Civilised societies are open, peaceful and sociable, and their citizens are as a result much happier. It is therefore not fair to characterise him, as Leslie Stephen did, as favouring "that stagnation which is the natural ideal of a skeptic". (Leslie Stephen, History of English Thought in the Eighteenth Century, 2 vols. (London: Smith, Elder and Co., 1876), vol. 2, 185.)

Though it has been suggested Hume had no positive vision of the best society, he in fact produced an essay titled Idea of a Perfect Commonwealth, which lays out what he thought was the best form of government. His pragmatism shone through, however, in his caveat that we should only seek to implement such a system should an opportunity present itself, which would not upset established structures. He defended a strict separation of powers, decentralisation, extending the franchise to anyone who held property of value and limiting the power of the clergy. The Swiss militia system was proposed as the best form of protection. Elections were to take place on an annual basis and representatives were to be unpaid.

Contributions to economic thought

Through his discussions on politics, Hume developed many ideas that are prevalent in the field of economics. This includes ideas on private property, inflation, and foreign trade.

Hume does not believe, as Locke does, that private property is a natural right, but he argues that it is justified since resources are limited. If all goods were unlimited and available freely, then private property would not be justified, but instead becomes an "idle ceremonial". Hume also believed in unequal distribution of property, since perfect equality would destroy the ideas of thrift and industry, which leads to impoverishment.

Hume did not believe that foreign trade produced specie, but considered trade a stimulus for a country’s economic growth. He did not consider the volume of world trade as fixed because countries can feed off their neighbors' wealth, being part of a "prosperous community". The fall in foreign demand is not that fatal, because in the long run, a country cannot preserve a leading trading position.

Hume was among the first to develop automatic price-specie flow, an idea that contrasts with the mercantile system. Simply put, when a country increases its in-flow of gold, this in-flow of gold will result in price inflation, and then price inflation will force out countries from trading that would have traded before the inflation. This results in a decrease of the in-flow of gold in the long run.

Hume also proposed a theory of beneficial inflation. He believed that increasing the money supply would raise production in the short run. This phenomenon would be caused by a gap between the increase in the money supply and that of the price level. The result is that prices will not rise at first and may not rise at all. This theory was later developed by John Maynard Keynes.

As Historian of England

Between Hume's death and 1894, there were at least 50 editions of his 6-voume History of England, a work of immense sweep. The subtitle tells us as much, "From the Invasion of Julius Caesar to the Revolution in 1688."

There was also an often-reprinted abridgement, The Student’s Hume (1859).

Hume's history was that of a Tory, in sharp contrast to the Whiggish works then prevailing.

Another remarkable feature of the series was that it widened the focus of history, away from merely Kings, Parliaments, and armies, including literature and science as well.

Works

• A Kind of History of My Life (1734) Mss 23159 National Library of Scotland.

A letter to an unnamed physician, asking for advice about "the Disease of the Learned" that then afflicted him. Here he reports that at the age of eighteen "there seem'd to be open'd up to me a new Scene of Thought… " which made him "throw up every other Pleasure or Business" and turned him to scholarship.

• A Treatise of Human Nature: Being an Attempt to introduce the experimental Method of Reasoning into Moral Subjects. (1739–40)

Hume intended to see whether the Treatise met with success, and if so to complete it with books devoted to Politics and Criticism. However, it did not meet with success (as Hume himself said, "It fell dead-born from the press, without reaching such distinction as even to excite a murmur among the zealots"), and so was not completed.

• An Abstract of a Book lately Published: Entitled A Treatise of Human Nature etc. (1740)

Anonymously published, but almost certainly written by Hume in an attempt to popularise his Treatise. Of considerable philosophical interest, because it spells out what he considered "The Chief Argument" of the Treatise, in a way that seems to anticipate the structure of the Enquiry concerning Human Understanding.

• Essays Moral and Political (first ed. 1741–2)

A collection of pieces written and published over many years, though most were collected together in 1753-4. Many of the essays are focused on topics in politics and economics, though they also range over questions of aesthetic judgement, love, marriage and polygamy, and the demographics of ancient Greece and Rome, to name just a few of the topics considered. The Essays show some influence from Addison's Tatler and The Spectator, which Hume read avidly in his youth.

• A Letter from a Gentleman to His Friend in Edinburgh: Containing Some Observations on a Specimen of the Principles concerning Religion and Morality, said to be maintain'd in a Book lately publish'd, intituled A Treatise of Human Nature etc. Edinburgh (1745).

Contains a letter written by Hume to defend himself against charges of atheism and scepticism, while applying for a Chair at Edinburgh University.

• An Enquiry concerning Human Understanding (1748)

Contains reworking of the main points of the Treatise, Book 1, with the addition of material on free will (adapted from Book 2), miracles, the Design Argument, and mitigated scepticism.

• Of Miracles

section X of the Enquiry, often published separately

• An Enquiry Concerning the Principles of Morals (1751)

A reworking of material from Book 3 of the Treatise, on morality, but with a significantly different emphasis. Hume regarded this as the best of all his philosophical works, both in its philosophical ideas and in its literary style.

• Political Discourses, (part II of Essays, Moral, Political, and Literary within vol. 1 of the larger Essays and Treatises on Several Subjects) Edinburgh (1752).

Included in Essays and Treatises on Several Subjects (1753–6) reprinted 1758–77.

• Four Dissertations London (1757).

Included in reprints of Essays and Treatises on Several Subjects (above).

• The History of England (Originally titled The History of Great Britain) (1754–62) Freely available in six vols. from the On Line Library of Liberty.

More a category of books than a single work, Hume's history spanned "from the invasion of Julius Caesar to the Revolution of 1688" and went through over 100 editions. Many considered it the standard history of England until Thomas Macaulay's History of England.

• The Natural History of Religion (1757) ISBN 0-8047-0333-7
• "My Own Life" (1776)

Penned in April, shortly before his death, this autobiography was intended for inclusion in a new edition of "Essays and Treatises on Several Subjects". It was first published by Adam Smith who claimed that by doing so he had incurred "ten times more abuse than the very violent attack I had made upon the whole commercial system of Great Britain". ( Ernest Campbell Mossner, The Life of David Hume)

• Dialogues concerning Natural Religion (1779)

Published posthumously by his nephew, David Hume the Younger. Being a discussion among three fictional characters concerning arguments for the existence of God, most importantly the argument from design. Despite some controversy, most scholars agree that the view of Philo, the most skeptical of the three, comes closest to Hume's own.

Hume's Influence

Attention to Hume's philosophical works grew after the German philosopher Immanuel Kant credited Hume with awakening him from "dogmatic slumbers" (circa 1770).

According to Schopenhauer, "There is more to be learned from each page of David Hume than from the collected philosophical works of Hegel, Herbart, and Schleiermacher taken together."

A. J. Ayer (1936), introducing his classic exposition of logical positivism, claimed: "the views which are put forward in this treatise derive from the logical outcome of the empiricism of Berkeley and Hume". Albert Einstein (1915) wrote that he was inspired by Hume's positivism when formulating his Special Theory of Relativity. Hume was called "the prophet of the Wittgensteinian revolution" by N. Phillipson, referring to his view that mathematics and logic are closed systems, disguised tautologies, and have no relation to the world of experience. David Fate Norton (1993) asserted that Hume was "the first post-sceptical philosopher of the early modern period".