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What is the difference between an atheist and an agnostic?

Atheism is about belief. Agnosticism is about knowledge. A person can be an agnostic atheist or an agnostic theist. Christians say God has made himself known.

Updated 2026-10-09 · Agnosticism

Part of Common arguments

On this page

An atheist is answering whether they believe a god exists. An agnostic is answering whether they know. The two words are not ranks of the same doubt. A person can lack belief and also say they do not know, and a person can believe and still say they do not know.

Key points

  • American Atheists say “Agnostic” isn’t a “weaker” version of being an atheist. Atheism is about what you believe. Agnosticism is about what you know.
  • Atheist Alliance International says theism and atheism tell what a person believes, and agnosticism tells what a person claims to know.
  • On that page, an agnostic atheist “does not believe in any gods but does not claim to know that no gods exist,” and an agnostic theist “believes in God but does not claim to know God exists.”
  • The Stanford Encyclopedia of Philosophy records atheism both as a lack of belief and as the proposition that God does not exist, so “atheist” is not one sentence in every book.
  • Huxley coined “agnostic” for the refusal to pretend that an undemonstrated conclusion is certain.
  • Christians say God has shown himself in what he made, Romans 1:20For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse:Romans 1:20 · King James Version, and that Jesus is God, John 1:1In the beginning was the Word, and the Word was with God, and the Word was God.John 1:1 · King James Version and John 20:28And Thomas answered and said unto him, My LORD and my God.John 20:28 · King James Version.

Two questions

American Atheists, What is an atheist?:

“Agnostic” isn’t a “weaker” version of being an atheist. It answers a different question. Atheism is about what you believe. Agnosticism is about what you know.

American Atheists, What is an atheist?

Atheist Alliance International, What is atheism?:

Theism and atheism tell us about a person’s belief in gods. Agnosticism and Gnosticism tell us what a person claims to know, not what they believe.

Atheist Alliance International, What is atheism?

An agnostic atheist does not believe in any gods but does not claim to know that no gods exist.

Atheist Alliance International, What is atheism?

It is possible to be an agnostic theist—a person who believes in God but does not claim to know God exists.

Atheist Alliance International, What is atheism?

Calling someone “just an agnostic” does not say whether they believe. Calling someone an atheist, in these organizations’ definitions, does not say whether they claim to know.

Where the words still overlap

The Stanford Encyclopedia of Philosophy, Atheism and Agnosticism says that in one sense “atheism is the psychological state of lacking the belief that God exists,” and that philosophy’s standard use is “the proposition that God does not exist.” If a speaker means the second, “atheist” already includes a denial. If a speaker means the first, “atheist” does not. The organizations quoted above use the first. The encyclopedia records both and says some atheists proudly call themselves “agnostic atheists.”

Huxley, Agnosticism (1889) tied his word to a method:

In matters of the intellect, do not pretend that conclusions are certain which are not demonstrated or demonstrable.

That sentence limits a knowledge claim. It does not say whether the person believes. The types, and what agnostics hold in common, are What is agnosticism?. What atheist organizations say atheists share is What do atheists believe?.

The Christian claim

Christians answer both questions. They believe God exists, and they say God has made himself known.

Romans 1:20For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse:Romans 1:20 · King James Version, King James Version:

For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse:

Romans 1:20 · King James Version

John 1:1In the beginning was the Word, and the Word was with God, and the Word was God.John 1:1 · King James Version, King James Version:

In the beginning was the Word, and the Word was with God, and the Word was God.

John 1:1 · King James Version

John 20:28And Thomas answered and said unto him, My LORD and my God.John 20:28 · King James Version, King James Version:

And Thomas answered and said unto him, My LORD and my God.

John 20:28 · King James Version

The God this confession names is the Father, the Son, and the Holy Spirit. Jesus is God. Does God exist? is that claim at length. The Trinity is the confession of who that God is.

Frequently asked questions

Is an agnostic an atheist who is less sure?

American Atheists say no. Agnosticism is not a weaker atheism. It answers whether a person knows, not whether a person believes.

Can a Christian be agnostic in Huxley’s sense?

Huxley’s method refuses to treat an undemonstrated conclusion as certain. The Christian claim is that God has shown what may be known of him, Romans 1:19–201:19 Because that which may be known of God is manifest in them; for God hath shewed it unto them. 1:20 For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse:Romans 1:19–20 · King James Version, and that Jesus is the way to the Father, John 14:6Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me.John 14:6 · King James Version. That is a knowledge claim, not a suspension of both belief and knowledge.

Which page is about God’s existence itself?

Does God exist?. This page is only the difference between the two words.

Keep reading

References

  1. American Atheists, What is an atheist?, Agnosticism
  2. Atheist Alliance International, What is atheism?, Agnosticism
  3. Stanford Encyclopedia of Philosophy, Atheism and Agnosticism, Definitions
  4. T. H. Huxley, Agnosticism, Popular Science Monthly, April 1889
  5. Gospel of John, 1:1; 20:28In the beginning was the Word, and the Word was with God, and the Word was God.John 1:1 · King James Version. King James Version
  6. Letter to the Romans, 1:19–201:19 Because that which may be known of God is manifest in them; for God hath shewed it unto them. 1:20 For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse:Romans 1:19–20 · King James Version. King James Version

See also

  • What is agnosticism? — Agnosticism is about what a person claims to know. Huxley coined the word. It covers weak and strong forms, and both agnostic theists and agnostic atheists.
  • What do atheists argue against God? — Atheist writers argue from a lack of good reasons to believe, and from suffering. This page is that case in their words, then the Christian claim.
  • What do atheists believe? — Atheist organizations say atheism is the lack of belief in gods. Some atheists also claim that no God exists. Those are different positions.
  • The Trinity — Christians confess that the one God is the Father, the Son, and the Holy Spirit: not three gods, and not one person taking turns.
  • Do Muslims and Christians Worship the Same God? — Is Allah the same God? Muslims and Christians both confess one Creator, the God of Abraham. They do not confess the same account of who that God is: Christians say Jesus is God, and the Qur'an denies it.

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