One of the great joys of the Renaissance, Reformation and Enlightenment was the freedom philosophers, scholars and ordinary people acquired to think for themselves. Hence the search for proofs of the unprovable, for the qualities of the ineffable, and for facts about the unknowable. Today we take this freedom for granted, and equally cheerfully slide over some deep philosophical difficulties. Not so for the Scottish philosopher David Hume, whose own epistemology has been no less influential than that of Descartes and Locke in shaping Western thought. Much of Hume’s philosophical writings are necessarily deep and abstract, but others are set in more familiar terms and deal with readily appreciated (if still dangerous) questions.
Hume was born in Edinburgh in 1711 and had early trained for the law – a subject that appealed to him about as much as medicine at Edinburgh later attracted Charles Darwin. His passion was for a wide learning based in philosophy, starting with the classics of Cicero and Virgil. He had been a delicate young man, in large part because of his intense studying and, evidently, hypochondria. To help recover from a depression or mental breakdown, he travelled to France, living as frugally as possible, and eventually spent two years at La Fleche in Anjou where he had access to the library of the Jesuit college. It was here that he wrote his monumental work, A Treatise of Human Nature (published between 1739 and 1740). At the college, the same institution where Descartes had studied, he heard a Jesuit teacher explaining a recent ‘miracle’ and immediately wrote out a rebuttal of the whole concept. For Hume, the miracles reported in the New Testament were ‘a contest of opposites … that is to say, a question whether it be more impossible that the miracle be true, or the testimony real’. For its day, that was almost as heretical as the present-day argument that some, if not all, of the miracles are mere fictions, constructed as a mythology around which to unite the fledgling first-century Christian Church.
Hume aimed to elevate moral philosophy to a science following the examples of Bacon and Newton in natural philosophy. A sceptic, he lost his faith very early, perhaps when a student at Edinburgh. The Treatise of Human Nature was the foundation of his later fame, even though the book earned little for him at first; in fact it was a commercial failure and a bitter disappointment, Hume wryly complaining that it ‘fell still-borne from the press’. Needing to earn a better living than his pen afforded, he spent a curious period first as a tutor to the insane son of the Marquis of Annandale and then as secretary and judge-advocate to General St Clair on an expedition against the French at Port Lorient, Guernsey, at the end of the War of the Austrian Succession. While now relatively hale and hearty, the life of a man of action scarcely suited him, but attempts to procure a more suitable position, a chair at Glasgow then one at Edinburgh, failed.
Following the death of his mother he returned to the family home in Scotland and began a period of great productivity, during which, in 1751, he wrote two works that had special bearing on an evolving, perhaps revolutionised, view of religion. In his Natural History of Religion (1757) and Dialogues Concerning Natural Religion (only published after his death in 1779)31 he used all his powers of reason and argument to test the case for traditional revealed religion as opposed to the deist position, that everything that was important about religion could be (must be) derived by reason alone. In the Dialogues Hume carefully covered his tracks by laying out his arguments in the form of a conversation among three different philosophers. This was the familiar philosopher’s device that Galileo used in his Dialogue concerning the two major world systems (1632) – without fooling the Inquisition. Both Galileo and Hume were following the example of Cicero’s De Natura Deorum, or On the Nature of the Gods (77 BC), which is set as a debate among Epicurean, Stoic and Academic philosophers.
Hume’s Dialogues did its damage not so much in the conclusions it reached as in daring to ask the awkward questions: What do we know that is true and independently verifiable about God, as opposed to what we are told? How do we know? Hume even asked the evolutionary question: Is it not more logical to assume that complex living creatures had their origins in simpler ones than via some miraculous creation by an infinitely powerful, but nonetheless unknowable, designing intelligence? Hume challenged everyone who thought they could find a rational basis for understanding God. He expressed the problem very simply: If we had never thought about there being a God in the first place, would objective, rational investigation and argument necessarily uncover his existence and define his nature? If we are already sure that God exists, it is not difficult to find seemingly rational arguments to support that notion and even to conclude that God must have certain specifiable ‘properties’, but if we were to start from scratch – if we were immigrants from some distant pagan shore or outer space – would objective study of the natural world and deep philosophical enquiry produce ineluctable proofs of God? Would there be miracles and signs, for instance, that could not be explained away rationally? Was Voltaire right when he said that if God did not exist, it would be necessary to invent him?
And we always have to worry about the final ace that Hume has up his sleeve: logically, he says, anything that can be imagined as existing can also be imagined as not existing. For every piece of evidence we can find for the Creator, we have to allow the existence of equally powerful evidence against. Hence Paley’s dilemma.
As for religion itself, it would be wrong to think of it as having been a passive spectator at these feasts of the intellect. Indeed, the Church and the churches became their own best and worst friends. Ever since Martin Luther in 1517 nailed his Ninety-five Theses to the church door in Wittenberg and unleashed a flood of independent thinking about forms of worship and modes of belief, it had become impossible for the Church to speak with one voice and proclaim one doctrine. Instead, many voices, doctrines and practices competed for people’s attention. A single original discipline had been opposed by a structureless freedom reaching to the heart of belief. Each group was defined on nuances of doctrine and separate routes to personal salvation, defended in the name of reason.
One such argument was between the theists and deists over the critical matter of revelation. For the Christian Church, revelation meant the events, especially the miracles, by which God had communicated with his chosen people, and it especially meant God’s self-revelation in the form of his son Jesus, sent for the redemption of our souls. Deists, however, insisted that revelation was just the public-relations machinery of a controlling priesthood. God was enough to stand on his own, with the vast panoply of nature itself forming the only necessary evidence of his Being. In the Age of Reason, therefore, rational study of the world alone could reveal the Unworldly One. As Thomas Paine (of American Revolution fame) was to write in his deist manifesto:
When the divine gift of reason begins to expand itself in the mind and calls man to reflection, he then reads and contemplates God and his works, not in the books pretending to revelation … The little and paltry, often obscene, tales of the bible sink into wretchedness when put in comparison with this mighty work. The deist needs none of those tricks and shows called miracles to confirm his father, for what can be a greater miracle than creation itself, and his own existence.32
Trinitarians opposed Unitarians, Arians and dozens of other sects over the