Atheism is defined as: without theism, without belief in god or gods, the absence of theism, the absence of belief in gods. This is the most basic and general definition of atheism, the definition which accurately describes all atheists, and the definition which encompasses all forms of or variations on atheism. It is also a disputed definition because many religious theists insist on defining atheism more narrowly.
Dictionaries can also define atheism more narrowly as the rejection of belief in gods and even more narrowly yet as the conscious denial of the existence of any gods. These narrower definitions are true of some atheists, but not necessarily all.
The Oxford English Dictionary, Second Edition, offers the follow definitions that are relevant to correctly defining atheism:
a-, prefix: from Gr. ...pref. of privation or negation = without, not, -less, in words introd. into Eng. through L. and Fr. as abysm, adamant, amethyst; or through L. as acatalectic, adiaphorous, apetalous; or from Gr. direct (or through a mod. lang.) as amorphous, adipsy; or formed on Gr. elements, as abiogenetic, agnostic. In the latter case, a- has become a living prefix of negation = un-, non-, applied not only to words from Gr., as a-cotyledonous, a-chromatic, a-philanthropy, but also to technical words from L., as a-caulous, a-sexual.
theism: a. gen. Belief in a deity, or deities, as opposed to atheism. b. Belief in one god, as opposed to polytheism or pantheism; = monotheism. c. Belief in the existence of God, with denial of revelation: = deism. d. esp. Belief in one God as creator and supreme ruler of the universe, without denial of revelation: in this use distinguished from deism.
atheism: Disbelief in, or denial of, the existence of a God. Also, Disregard of duty to God, godlessness (practical atheism).
disbelief: The action or an act of disbelieving; mental rejection of a statement or assertion; positive unbelief.
disbelieve: 3. intr. with in: Not to believe in; to have no faith in: cf. believe 1, 3.
believe: 1. To have confidence or faith in (a person), and consequently to rely upon, trust to. 3. To believe in (a person or thing), i.e. in its actual existence or occurrence.
Atheism can thus encompass outright denial of the existence of gods, lack of interest in the existence of gods, and disbelief due to a lack of information.
"Atheism is a non-prophet organization."
- George Carlin
"Atheism is nothing more than the noises reasonable people make when in the presence of religious dogma."
- Sam Harris
