QuestionsDoes God exist?Do not claim to know what you do not know
Does God exist?AgnosticismThe burden of proof

Do not claim to know what you do not know

Agnosticism

Thomas Henry Huxley 1825 · 1895He coined the word 'agnostic': not claiming to know what cannot be known.
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What it claims

On God the honest stance is neither theism nor atheism, but agnosticism: admitting that we do not know.

Why

Claiming certainty without enough proof is wrong, and reason has not settled God's existence: believing or denying both claim to know.

The same idea through history
David Hume1748Huxley says he has Hume and Kant on his side, and calls Hume "that prince of agnostics": the wise man proportions his belief to the evidence.
Thomas Henry Huxley1869Around 1869, at the Metaphysical Society in London, he coins the word "agnostic", in contrast with the "gnostics" who claimed to know everything. He explains the word and his method in three essays of 1889.
Bertrand Russell1952Russell takes up the idea: whoever asserts must prove. He calls himself an agnostic in the strict sense, but draws a stronger conclusion from the teapot: there is no reason to believe.
In short

"Do not claim to know what you do not know" is an argument by Thomas Henry Huxley ("Agnosticism" and "Agnosticism and Christianity", 1889, 1869) on the question "Does God exist?" (answer: agnosticism). Its claim: On God the honest stance is neither theism nor atheism, but agnosticism: admitting that we do not know. According to AskPhilosophy's logic check (Z3 solver), the argument is valid only if one grants a premise the author leaves unstated (P4). AskPhilosophy presents 4 objections, 1 of them with a documented reply, and the original text behind each premise, checked word for word.

"Agnosticism" and "Agnosticism and Christianity", 1889
Valid with an implicit premise

The word "agnostic" has an inventor: the biologist Thomas Huxley, Darwin's friend and defender. Around him, he tells us, everyone had a label: atheist, theist, pantheist, materialist. All were sure they had solved the riddle of existence. He was sure of the opposite. So he coined a word, from the Greek gnosis (knowledge): the agnostic is someone who does not claim to know. For Huxley this is not one more creed but a method: follow reason as far as it goes, and do not call yourself certain of what is not proved. Applied to God, the method gives neither "God exists" nor "God does not exist", but "I do not know".

P1It is wrong (morally as much as intellectually) to say one is certain that something is true unless one can give evidence that logically justifies that certainty.
P2In matters of the intellect, the only rule is to follow reason as far as it will take you, without regard to anything else (authority, tradition, the advantage of believing).
P3Yet on God, reason has not settled the matter. For twenty-five centuries theism and atheism have refuted each other and come back to life without end: neither God's existence nor his non-existence has been demonstrated.
P4 · implicit premiseTo call oneself a theist or an atheist is to claim to know: to assert that one has the answer, that God exists or that he does not.
Therefore on God the honest stance is neither theism nor atheism, but agnosticism: admitting that we do not know.

click a premise to reject it

If you accept every premise, logic forces you to accept the conclusion. So the debate is about the premises.
Checked by a logic solver: the premises cannot all be true while the conclusion is false.
Without the implicit premise: Without P4 the computer finds a case where there is no proof either way, where one therefore claims certainty about nothing, and where one still rightly calls oneself a theist (or an atheist): someone who believes, or who says "I have no reason to believe", without claiming to know.
With P4 the argument is valid. Without P4 it no longer is: Huxley only forbids calling oneself certain without proof. If one can be an atheist (or a believer) without claiming certainty, for instance by only judging God's existence very improbable, his rule no longer requires neutrality. That is the point the critics aim at: for Engels, the agnostic is a "shamefaced" materialist who dare not say so. Huxley himself grants that he may have "a tolerably strong opinion as to the probabilities".
Analogy. You are asked whether there is life on a planet in another galaxy. You have no idea, and nobody does. Answering "yes, I am sure" or "no, I am sure" would be cheating. The honest answer is "I don't know", even if you have a hunch.

Objections

4

Each objection is a conversation: click to see who replies and where the debate stands.

H
Henry Wace (Principal of King's College London) 1888 · attacks the conclusion

The agnostic hides behind a new word. The difference between him and the Christian is not that he does not know: it is that he does not believe the authority that teaches these things. His real name is an older one: he is an "infidel", an unbeliever. That ought to be unpleasant to say, and rightly so.

Huxley replies
Huxley 1889 · Huxley's reply
The charge is false: the word was not born to escape the name of "infidel", and I have told how it was born. Agnosticism is not a negative creed, it is a principle: do not claim certainty without evidence. Churchmen have the right to call me an "infidel", but they must not expect me to call myself by that name.
H
Henry Wace 1889 · Wace stands firm
The real question is not whether agnosticism is justified, but what it implies. Justified or not, it amounts to denying the beliefs in which Jesus lived and died. One cannot be agnostic about the elementary truths of religion without rejecting the authority of Christ.
The debate goes on (our summary) Both are right about something. Wace: in practice, not believing means not following the Christian faith. Huxley: "I do not know" and "I deny" are not the same thing. The basic disagreement remains: may one believe on the authority of a master or a Church, without proof?
F
Friedrich Engels 1892 · attacks premise 4

The agnostic is a "shamefaced" materialist. He thinks that all of nature is governed by laws and that no action from outside intervenes in it; he merely adds that a Supreme Being beyond the universe can be neither proved nor disproved. In nature as he conceives it there is no room for a creator: he is a materialist who dare not say his name.

no reply
We have not yet found a direct reply by Huxley in the texts.
The debate goes on (our summary) Huxley did not reply to Engels. But he himself counts materialism among the questions reason has not settled, alongside theism and atheism: so he also refuses the label of materialist. The question remains open: if one judges God very improbable, is one not already an atheist, in the sense of "no good reason to believe"?
Pascal 1670 · attacks the conclusion

One cannot stay neutral about God. "You must wager. It is not optional. You are embarked." Not choosing is living as if God did not exist: the agnostic has already wagered without saying so (see the wager argument).

no reply
We have not yet found a direct reply by Huxley in the texts.
The debate goes on (our summary) No reply by Huxley to Pascal was found. His rule is about what one claims to know, not about how to live: one can act without being certain. But Pascal is speaking precisely about life, not knowledge, and that is what William James will take up against Huxley.
William James ("The Will to Believe") 1896 · attacks the conclusion

When a question is vital, when one cannot avoid choosing and reason cannot decide, saying "let us not decide, let us leave the question open" is already a decision, made by the heart, and it runs just as much risk of missing the truth. James quotes Huxley among those he opposes. For him, this scepticism is not intellect against passion: it is intellect led by one passion, the fear of being wrong, put before hope.

no reply
No reply possible: objection raised in 1896, after the author's death (1895).
The debate goes on (our summary) Huxley died in 1895, before James's essay. On Huxley's side, one can answer that his rule is about what one claims to know: one can act, hope or wager without calling oneself certain. Russell will also answer James: a useful belief is not thereby true (see "The celestial teapot").
In the same family · The burden of proof
The celestial teapot: who must prove it?Bertrand Russell
Does God exist?Atheism 4