What Is Agnosticism?

What Is the Question?

Agnosticism sits between theism and atheism, but it is not a timid compromise. The term was coined by the English biologist T. H. Huxley in 1869, at a meeting of the Metaphysical Society, where he wanted a word for the position he had come to hold: that the existence of God, like the origin of life, was beyond the reach of the evidence then available. He took the word from the Greek a-gnostos, "not known," and he meant it as a stance of intellectual honesty. The question for us is what the stance amounts to, and whether it is coherent.

The IEP article on atheism treats agnosticism as a subcategory of negative atheism, since the agnostic withholds belief. But many agnostics resist the assimilation, insisting that agnosticism is not about belief at all but about knowledge, and that one can be an agnostic theist (believing without claiming to know) as well as an agnostic atheist. The philosophical work is to keep these distinctions clean.

Historical Background

Huxley coined the word, but the stance is ancient. Protagoras, in the fifth century BCE, famously said that he could not know whether the gods exist, because the question is too hard and human life is too short. The ancient Skeptics, both Pyrrhonian and Academic, recommended suspending judgment on questions that outrun the evidence. In the modern period, David Hume is the patron saint of the agnostic spirit: his critiques of miracles and of natural theology argued not that theism is false but that the arguments for it fall short of demonstration.

Kant gave the stance its deepest philosophical grounding. In the Critique of Pure Reason, he argued that speculative reason cannot reach beyond experience to determine whether God exists. The ideas of reason, including God, function as regulative ideals, guiding inquiry without being objects of knowledge. Kant's stance is not that we know God does not exist, but that theoretical reason cannot settle the question, which leaves room for moral faith without theoretical knowledge.

The late nineteenth century saw a flowering of explicit agnosticism among British intellectuals, including Huxley, Herbert Spencer, and Leslie Stephen. They were reacting against both dogmatic theology and dogmatic materialism, insisting that the limits of human knowledge be respected. The stance was controversial: believers called it cowardly unbelief, and atheists like Charles Bradlaugh called it a polite cover for atheism. Huxley's reply was that he had no use for a faith that required pretending to know what one did not know, and no use for a denial that pretended to more than the evidence warranted.

Key Varieties

The first distinction is between weak and strong agnosticism. Weak agnosticism says we do not, at present, know whether God exists, but leaves open the possibility that further inquiry or revelation might settle it. Strong agnosticism says we cannot know, in principle, because the question outruns our cognitive capacities or the available evidence is structurally insufficient. The strong version is the more philosophically interesting and the more controversial, because it claims a limit on what we can know, and such claims are notoriously hard to defend.

A second distinction concerns the object of the claim. Some agnostics suspend judgment on classical theism while allowing for thinner conceptions of the divine, such as pantheism or deism, on the grounds that those conceptions are harder to refute and may be supported by philosophical argument. The question "do you know whether God exists?" is ambiguous until we know which God is meant, just as with atheism.

A third distinction is practical. Some agnostics suspend belief and live as if the question is open; others, having suspended belief, live as if there is no God, on the principle that one should not order one's life around an unproven hypothesis. The latter stance is sometimes called "practical atheism," and it is the one most agnostics actually occupy, even if they insist on the label "agnostic" to signal their epistemic humility.

The Argument from Insufficient Evidence

The strongest agnostic argument is that the evidence, on either side, is insufficient to ground knowledge. Huxley's original formulation turned on the principle that one should not affirm or deny what one cannot substantiate. Hume made the same point in his discussion of miracles: a wise person proportions belief to the evidence, and where the evidence is balanced, suspension is the only intellectually honest stance.

The agnostic can point to the persistence of reasonable disagreement about God's existence as evidence that the question is not settled. Brilliant philosophers, using the best arguments, have reached opposite conclusions. Theists cite the cosmological, teleological, and moral arguments, religious experience, and the conviction of billions of believers. Atheists cite the problem of evil, divine hiddenness, and the failure of theistic proofs. The agnostic takes the standoff seriously as a fact about our epistemic situation, not as a temporary embarrassment to be resolved by a better argument.

The Challenge: Is "Cannot Know" Coherent?

The deepest challenge to agnosticism, raised by both theists and atheists, is whether the strong claim that we cannot know is itself too strong. The theist may say that natural theology and revelation give us genuine knowledge; the atheist may say that the problem of evil gives us knowledge that no good God exists. To both, the agnostic's "cannot know" looks like a refusal to follow the arguments where they lead.

The agnostic reply is that the arguments, on both sides, are stronger as challenges than as proofs. The problem of evil is a serious difficulty for theism but does not prove atheism, because the free will defense and the greater-goods theodicy are not refuted. The cosmological and teleological arguments give theism some support but do not prove a personal God. The agnostic insists that the balance of considerations, weighed carefully, does not amount to knowledge, and that the honest stance is to say so.

There is also a more subtle agnostic move, associated with Pascal. If the question of God's existence cannot be settled by reason, then the practical question of how to live becomes primary, and the rationality of faith may depend on practical considerations rather than theoretical proof. Pascal's Wager tries to show that, in the face of agnosticism about proof, the expected utility of betting on God favors the bet. The philosophical literature has debated the wager ever since.

Agnosticism and the Burden of Proof

The agnostic has a distinctive view of the burden of proof. Both theists and atheists bear it: the theist because they affirm God, the atheist (if positive) because they deny God. The agnostic refuses both affirmations and so declines both burdens, while also declining to declare the question meaningless. The agnostic says the question is meaningful and important, just not settled.

This stance is harder than it looks. The agnostic must defend the claim that the evidence is genuinely balanced, which requires engaging with the arguments on both sides. The shallow agnostic who has not studied the arguments and simply says "who knows?" is a caricature; the serious agnostic, like Huxley or Hume, has done the work and concluded that the work does not settle the question.

Contemporary Relevance

Agnosticism has become culturally significant as the "nones," people with no religious affiliation, have grown in Western societies. Many of them are agnostics in Huxley's sense: not committed atheists, but not believers, occupying the space of suspended judgment. The rise of New Atheism, with its more assertive tone, has paradoxically made agnosticism more visible as the philosophical alternative that resists both dogmatic belief and dogmatic denial.

The deeper contemporary issue is whether agnosticism is a stable resting place. Some philosophers, including Basil Mitchell and Richard Swinburne, argue that the cumulative case for theism, even if no single argument is conclusive, tips the balance. Others, including the New Atheists, argue that the cumulative case tips the other way. The agnostic's reply is that the scales are still level, and that saying so is not weakness but epistemic honesty.

Sources

• Internet Encyclopedia of Philosophy, "Atheism" (agnosticism section) — https://iep.utm.edu/atheism/
• Stanford Encyclopedia of Philosophy, "Philosophy of Religion" — https://plato.stanford.edu/entries/philosophy-religion/
• Stanford Encyclopedia of Philosophy, "David Hume" — https://plato.stanford.edu/entries/hume/
• Stanford Encyclopedia of Philosophy, "Kant's Philosophy of Religion" — https://plato.stanford.edu/entries/kant-religion/

Related Topics

• What Is Atheism? — the related absence-of-belief stance.
• Is Faith Rational? — the question that agnosticism raises.
• Who Bears the Burden of Proof for God? — the procedural question.
• Does God Exist? — the central question.
• What Is Natural Theology? — the theistic evidence.
• Philosophy of God — the wider domain.