Atheism is the state of disbelief or non-belief in the existence of a deity or deities. It is commonly defined as the positive denial of theism (i.e., the assertion that deities do not exist), or the deliberate rejection of theism (i.e., the refusal to believe in the existence of deities). However, others—including most atheistic philosophers and groups—define atheism as the simple absence of belief in deities (cf. nontheism), thereby designating many agnostics, and people who have never heard of gods, such as the unchurched or newborn children, as atheists as well. In recent years, some atheists have adopted the terms strong and weak atheism to clarify whether they consider their stance one of positive belief that no gods exist (strong atheism), or of mere absence of belief that gods exist (weak atheism).