Dialogues Concerning Natural Religion by David Hume

Overview

Dialogues Concerning Natural Religion is David Hume's masterpiece in the philosophy of religion and one of the most important works in the Western philosophical tradition. Hume wrote it over a period of more than twenty years, beginning in the early 1750s and continuing to revise it until his death in 1776. He was so aware of its explosive potential — the Edinburgh of his day was a city where an atheist could be prosecuted — that he arranged for the manuscript to be published only after his death, with his friend the economist Adam Smith enlisted (reluctantly) to see it through the press. It appeared in 1779, three years after Hume's passing.

The book takes the form of a dialogue among three characters: Demea, the philosophical rationalist who defends theism through a priori reasoning and emphasizes the mysteriousness of God; Cleanthes, the empirical theist who argues that the order of the world proves the existence of a designer; and Philo, the skeptical philosopher whose objections to both positions dominate the conversation. The dialogue form allows Hume to distribute arguments among his characters without committing himself to any single position, and it lets him present the case for and against natural theology with a degree of dramatic and intellectual subtlety that no treatise could match.

The book's central target is the design argument — the argument, descending from Aquinas and articulated with new force by the natural theologians of Hume's own century, that the ordered complexity of the world is evidence of a designer. Hume's critique of this argument is the most influential in the history of philosophy of religion, and it set the terms for every subsequent debate about whether the world provides evidence of God's existence. The book also addresses the problem of evil, the nature of miracles, the limits of anthropomorphic language about God, and the question of whether any inference from the world to its cause is legitimate at all.

Key Ideas

The Design Argument and Its Limits

The core of the Dialogues is Cleanthes' presentation of the design argument and Philo's devastating critique of it. Cleanthes argues that the world resembles a machine — a watch, a ship, a living organism — and that by analogy with human artifacts, we should infer a designer. The argument is an inference to the best explanation: the order, complexity, and apparent purpose of the world are best explained by the hypothesis of an intelligent creator.

Philo's response takes several forms, and together they constitute the most thorough critique of the design argument ever mounted. The first objection is to the analogy itself. The inference from effect to cause, Philo argues, is only legitimate when the effect and the cause are of the same kind — when we are inferring from a watch to a watchmaker, or from a house to a builder. But the world is not a watch, and the inference from the world to a designer assumes that the cause of the world resembles the causes of human artifacts. The universe is more like an organism than a machine, and organisms do not require an external designer — they grow, develop, and reproduce by internal principles. If the analogy is with organic nature rather than with human artifacts, the design argument proves too much: it proves a designer who is itself organic, growing, and mortal, not the transcendent God of theism.

The second objection is to the strength of the conclusion. Even if we grant the analogy, Philo says, the most it proves is a designer of limited power, limited wisdom, and limited goodness. The world contains a great deal of disorder, evil, and waste; the designer, if there is one, is more like a bungling artisan than a perfect God. We cannot infer an infinite cause from a finite effect, and we cannot infer perfect goodness from a world that contains suffering. The design argument, even if it succeeds, yields at most a demiurge — a limited, imperfect creator — not the God of traditional theism.

The third objection is to the principle of inference itself. We infer causes from effects only when we have experience of the connection between them — when we have seen, repeatedly, that effects of this kind are produced by causes of that kind. But we have no experience of the creation of worlds. We have seen exactly one universe, and we cannot infer the cause of a unique event from the principles of ordinary experience. The inference from the world to a designer is not an inference from like to like but a speculation about something of which we have no experience, and the rules of empirical reasoning — the rules Hume himself had articulated in the Treatise and the Enquiry — do not license it.

The Problem of Evil in the Dialogues

The Dialogues also contain one of the most powerful presentations of the problem of evil in the philosophical literature. Demea opens the discussion with a lament about the miseries of human life — the suffering, the anxiety, the cruelty, the brevity — and argues that the very mystery of suffering should drive us to faith rather than away from it. But Philo turns the argument: if God is the cause of the world, then God is the cause of the evil in it, and the existence of evil is evidence against the goodness, if not the existence, of the designer.

The treatment is not a formal statement of the logical problem of evil — that formulation belongs to later philosophers — but it is the seed from which the tradition grows. Philo's point is that the design argument, which claims to infer the goodness of the designer from the goodness of the design, must also infer the designer's cruelty from the cruelty of the design. You cannot pick and choose: if the order of the world is evidence of a designer, the disorder and suffering are evidence of the same designer's limitations. The four causes that Aquinas identifies as evidence of God's perfection — goodness, power, wisdom, and providence — are all, on Philo's reading, challenged by the actual state of the world.

The A Priori Argument and the Limits of Reason

Demea represents the a priori tradition in natural theology — the tradition that argues from the necessity of a first cause or the contingency of the world to the existence of a necessary being. Philo and Cleanthes unite to demolish this approach. Cleanthes argues that there is nothing in the idea of a necessary being that makes its existence more than a verbal definition (a point later made famous by Kant), and Philo argues that the causal principle — the principle that everything has a cause — cannot be extended beyond the world of experience to the world as a whole. If we ask what caused the world, we can equally ask what caused the cause, and the regress either terminates arbitrarily or continues indefinitely. The a priori argument, on this reading, is a piece of metaphysical speculation that the empirical tradition cannot support.

This is where the dialogue form does its most important work. None of the three characters is simply Hume, and the reader is left to decide which position is closest to the truth. But the cumulative effect of Philo's objections is to leave the design argument and the a priori argument in ruins, and to suggest that the question of God's existence may not be answerable by the methods of natural theology. Philo, who speaks for most of the book, is officially a theist — he concedes at the end that the cause of the world probably bears some resemblance to human intelligence — but the concession is so hedged with qualifications that it amounts to almost nothing, and most readers have understood the Dialogues as a covert argument for something close to atheism or at least agnosticism.

Anthropomorphism and the Nature of the Divine

A recurring theme in the Dialogues is the problem of anthropomorphism — the tendency to attribute human qualities to God. Cleanthes' design argument, Philo argues, is anthropomorphic at its root: it infers a designer who resembles a human artisan, and it attributes human-like intelligence, purpose, and method to the cause of the world. But if the cause of the world is truly God — infinite, transcendent, unlike anything in creation — then the anthropomorphic inference is a category mistake. We are projecting our own minds onto the cosmos and calling the projection God.

This connects to Hume's broader empiricist critique of metaphysics. In the Enquiry Concerning Human Understanding, Hume had argued that meaningful ideas must be traceable to sense impressions, and that concepts that cannot be so traced are suspect. The concept of God, Philo suggests, is precisely such a concept: we build it up from human qualities — intelligence, goodness, power — and then project it onto the cosmos, but the projection gives us no knowledge of what the cause of the world is actually like. The honest empiricist, on Philo's view, must admit that the nature of the world's cause is unknown, and that the design argument tells us nothing about the character of the being it purports to prove.

Structure and Style

The dialogue form is central to the book's philosophical effect. By distributing the arguments among three characters, Hume ensures that no single position is presented as the final word, and the reader is forced to engage with the arguments rather than simply accepting a conclusion. The style is elegant, ironic, and conversational — Hume writes as a gentleman philosopher addressing other gentlemen, and the tone is one of urbane discussion rather than polemic. But beneath the civility, the arguments are devastating, and the cumulative effect of Philo's objections is to leave the reader with a profound skepticism about the capacity of natural theology to establish the existence and nature of God.

The book is also a work of character. Demea is the solemn rationalist, driven by piety and a love of mystery; Cleanthes is the confident empiricist, sure that the world speaks clearly of its maker; Philo is the ironic skeptic, who punctures both with equal elegance. The interplay among them gives the book a dramatic life that no treatise could have, and it allows Hume to present positions that, in his own voice, would have been inflammatory.

Legacy and Influence

Dialogues Concerning Natural Religion is the foundational text of the modern critique of natural theology. Every subsequent debate about the design argument — from William Paley's attempt to revive it, through the Darwinian revolution that gave it a new context, to the contemporary debates between Swinburne and the New Atheists — takes place in the shadow of Hume's arguments. The book's treatment of the problem of evil anticipates the formulations of John Hick and Alvin Plantinga, and its critique of anthropomorphism connects to the tradition of negative theology that runs from the Neo-Platonists through Kant to the present.

The book's influence is also visible in the broader culture. Hume's Philo is the model of the religious skeptic — the person who takes religion seriously enough to engage with its arguments but who refuses to accept conclusions that the evidence does not support. The tradition of skeptical theism, of philosophical agnosticism, of the insistence that the limits of reason must be respected — all of it descends, in one way or another, from the Dialogues. For readers approaching the philosophy of God and the question of whether God exists, the Dialogues remains the essential starting point: the book that defined the terms of the debate and that has not been surpassed in the two and a half centuries since it was written.