Atheism, in the broadest sense, is an absence of belief in the existence of deities. Less broadly, atheism is a rejection of the belief that any deities exist. In an even narrower sense, atheism is specifically the position that there are no deities. Atheism is contrasted with theism, which in its most general form is the belief that at least one deity exists.

Secularism is the principle of seeking to conduct human affairs based on naturalistic considerations, uninvolved with religion.