Religion
The philosopher Paul Russell contends that Hume wrote "on almost every central question in the philosophy of religion", and that these writings "are among the most important and influential contributions on this topic." Touching on the philosophy, psychology, history and anthropology of religious thought, Hume's 1757 dissertation "The Natural History of Religion" argues that the monotheistic religions of Judaism, Christianity and Islam all derive from earlier polytheistic religions. He went on to suggest that all religious belief "traces, in the end, to dread of the unknown". Hume had also written on religious subjects in the first Enquiry, as well as later in the Dialogues Concerning Natural Religion.
Although he wrote a great deal about religion, Hume's personal views have been the subject of much debate. Some modern critics have described Hume's religious views as agnostic or have described him as a "Pyrrhonian skeptic". Contemporaries considered him to be an atheist, or at least un-Christian, enough so that the Church of Scotland seriously considered bringing charges of infidelity against him. Evidence of his un-Christian beliefs can especially be found in his writings on miracles, in which he attempts to separate historical method from the narrative accounts of miracles. Nevertheless, modern scholars have tended to dismiss the claims of Hume's contemporaries describing him as an atheist as coming from religiously intolerant people who did not understand Hume's philosophy. The fact that contemporaries suspected him of atheism is exemplified by a story Hume liked to tell:
The best theologian he ever met, he used to say, was the old Edinburgh fishwife who, having recognized him as Hume the atheist, refused to pull him out of the bog into which he had fallen until he declared he was a Christian and repeated the Lord's prayer.
However, in works such as "Of Superstition and Enthusiasm", Hume specifically seems to support the standard religious views of his time and place. This still meant that he could be very critical of the Catholic Church, dismissing it with the standard Protestant accusations of superstition and idolatry, as well as dismissing as idolatry what his compatriots saw as uncivilised beliefs. He also considered extreme Protestant sects, the members of which he called "enthusiasts", to be corrupters of religion. By contrast, in "The Natural History of Religion", Hume presents arguments suggesting that polytheism had much to commend it over monotheism. Additionally, when mentioning religion as a factor in his History of England, Hume uses it to show the deleterious effect "superstition and fanaticism" has on human progress. In his Treatise of Human Nature, Hume wrote: "Generally speaking, the errors in religions are dangerous; those in philosophy only ridiculous."
Lou Reich (1998) argues that Hume was a religious naturalist and rejects interpretations of Hume as an atheist. Paul Russell (2008) writes that Hume was plainly sceptical about religious belief, although perhaps not to the extent of complete atheism. He suggests that Hume's position is best characterised by the term "irreligion", while philosopher David O'Connor (2013) argues that Hume's final position was "weakly deistic". For O'Connor, Hume's "position is deeply ironic. This is because, while inclining towards a weak form of deism, he seriously doubts that we can ever find a sufficiently favourable balance of evidence to justify accepting any religious position." He adds that Hume "did not believe in the God of standard theism ... but he did not rule out all concepts of deity", and that "ambiguity suited his purposes, and this creates difficulty in definitively pinning down his final position on religion".
One of the traditional topics of natural theology is that of the existence of God, and one of the a posteriori arguments for this is the argument from design or the teleological argument. The argument is that the existence of God can be proved by the design that is obvious in the complexity of the world, which Encyclopædia Britannica states is "the most popular", because it is:
...the most accessible of the theistic arguments ... which identifies evidences of design in nature, inferring from them a divine designer ... The fact that the universe as a whole is a coherent and efficiently functioning system likewise, in this view, indicates a divine intelligence behind it.
In An Enquiry Concerning Human Understanding, Hume wrote that the design argument seems to depend upon our experience, and its proponents "always suppose the universe, an effect quite singular and unparalleled, to be the proof of a Deity, a cause no less singular and unparalleled". The philosopher Louise E. Loeb (2010) notes that Hume is saying that only experience and observation can be our guide to making inferences about the conjunction between events. However, according to Hume:
We observe neither God nor other universes, and hence no conjunction involving them. There is no observed conjunction to ground an inference either to extended objects or to God, as unobserved causes.
Hume also criticised the argument in his Dialogues Concerning Natural Religion (1779). Hume proposes a finite universe with a finite number of particles. Given infinite time, these particles could randomly fall into any arrangement, including our seemingly designed world.
A century later, the idea of order without design was rendered more plausible by Charles Darwin's discovery that the adaptations of the forms of life result from the natural selection of inherited characteristics. For philosopher James D. Madden, it is "Hume, rivaled only by Darwin, [who] has done the most to undermine in principle our confidence in arguments from design among all figures in the Western intellectual tradition".
Finally, Hume discussed a version of the anthropic principle, which is the idea that theories of the universe are constrained by the need to allow for man's existence in it as an observer. Hume has his sceptical mouthpiece Philo suggest that there may have been many worlds, produced by an incompetent designer, whom he called a "stupid mechanic". In his Dialogues Concerning Natural Religion, Hume wrote:
Many worlds might have been botched and bungled throughout an eternity, ere this system was struck out: much labour lost: many fruitless trials made: and a slow, but continued improvement carried on during infinite ages in the art of world-making.
The philosopher Daniel Dennett suggested that this mechanical explanation of teleology, although "obviously ... an amusing philosophical fantasy", anticipated the notion of natural selection, the 'continued improvement' being like "any Darwinian selection algorithm".
In his discussion of miracles, Hume argues that we should not believe miracles have occurred and that they do not therefore provide us with any reason to think God exists. 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". Hume says we believe an event that has frequently occurred is likely to occur again, but we also take into account those instances where the event did not occur:
A wise man ... considers which side is supported by the greater number of experiments. ... A hundred instances or experiments on one side, and fifty on another, afford a doubtful expectation of any event; though a hundred uniform experiments, with only one that is contradictory, reasonably beget a pretty strong degree of assurance. In all cases, we must balance the opposite experiments ... and deduct the smaller number from the greater, in order to know the exact force of the superior evidence.
Hume discusses the testimony of those who report miracles. He wrote that testimony might be doubted even from some great authority in case the facts themselves are not credible: "[T]he evidence, resulting from the testimony, admits of a diminution, greater or less, in proportion as the fact is more or less unusual."
Although Hume leaves open the possibility for miracles to occur and be reported, he offers various arguments against this ever having happened in history. He points out that 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. Furthermore, people by nature enjoy relating miracles they have heard without caring for their veracity and thus miracles are easily transmitted even when false. Also, Hume notes that miracles seem to occur mostly in "ignorant and barbarous nations" and times, and the reason they do not occur in the civilised societies is such societies are not awed by what they know to be natural events. Hume recognises that over a long period of time, various coincidences can provide the appearance of intention. Finally, 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.
Hume was extremely pleased with his argument against miracles in his Enquiry. He states, "I flatter myself, that I have discovered an argument of a like nature, which, if just, will, with the wise and learned, be an everlasting check to all kinds of superstitious delusion, and consequently, will be useful as long as the world endures." Thus, Hume's argument against miracles had a more abstract basis founded upon the scrutiny, not just primarily of miracles, but of all forms of belief systems. It is a commonsense notion of veracity based upon epistemological evidence, and founded on a principle of rationality, proportionality and reasonability.
The criterion for assessing Hume's belief system is based on the balance of probability whether something is more likely than not to have occurred. Since the weight of empirical experience contradicts the notion for the existence of miracles, such accounts should be treated with scepticism. Further, the myriad of accounts of miracles contradict one another, as some people who receive miracles will aim to prove the authority of Jesus, whereas others will aim to prove the authority of Muhammad or some other religious prophet or deity. These various differing accounts weaken the overall evidential power of miracles.
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, thus it amounts to a subtle form of begging the question. To assume that testimony is a homogeneous reference group seems unwise – to compare private miracles with public miracles, unintellectual observers with intellectual observers and those who have little to gain and much to lose with those with much to gain and little to lose is not convincing to many. Indeed, many have argued that miracles not only do not contradict the laws of nature but require the laws of nature to be intelligible as miraculous, and thus subverting the law of nature. For example, William Adams remarks that "there must be an ordinary course of nature before anything can be extraordinary. There must be a stream before anything can be interrupted." They have also noted that it requires an appeal to inductive inference, as none have observed every part of nature nor examined every possible miracle claim, for instance those in the future. This, in Hume's philosophy, was especially problematic.
Little appreciated is the voluminous literature either foreshadowing Hume, in the likes of Thomas Sherlock or directly responding to and engaging with Hume—from William Paley, William Adams, John Douglas, John Leland and George Campbell, among others. Regarding the latter, it is rumoured that, having read Campbell's Dissertation, Hume remarked that "the Scotch theologue had beaten him."
Hume's main argument concerning miracles is that miracles by definition are singular events that differ from the established laws of nature. Such natural laws are codified as a result of past experiences. Therefore, a miracle is a violation of all prior experience and thus incapable on this basis of reasonable belief. However, the probability that something has occurred in contradiction of all past experience should always be judged to be less than the probability that either one's senses have deceived one, or the person recounting the miraculous occurrence is lying or mistaken, Hume would say, all of which he had past experience of. For Hume, this refusal to grant credence does not guarantee correctness. He offers the example of an Indian Prince, who, having grown up in a hot country, refuses to believe that water has frozen. By Hume's lights, this refusal is not wrong and the prince "reasoned justly;" it is presumably only when he has had extensive experience of the freezing of water that he has warrant to believe that the event could occur.
So, for Hume, either the miraculous event will become a recurrent event or else it will never be rational to believe it occurred. The connection to religious belief is left unexplained throughout, except for the close of his discussion where Hume notes the reliance of Christianity upon testimony of miraculous occurrences. He makes an ironic remark that anyone who "is moved by faith to assent" to revealed testimony "is conscious of a continued miracle in his own person, which subverts all principles of his understanding, and gives him a determination to believe what is most contrary to custom and experience." Hume writes that "All the testimony whichever was really given for any miracle, or ever will be given, is a subject of derision."
