Irreligion (adjective form: non-religious or irreligious) is the absence, indifference, rejection of, or hostility towards religion.
When characterized as the rejection of religious belief, it encompasses atheism, agnosticism, deism, religious dissidence, materialism, and secular humanism. When characterized as the absence of religious belief, it may also include "spiritual but not religious", pandeism, ignosticism, nontheism, pantheism, panentheism, and freethought. When characterized as indifference to religion, it is known as apatheism. When characterized as hostility towards religion, it encompasses antitheism, antireligion and misotheism.
Irreligion may include some forms of theism, depending on the religious context it is defined against; for example, in 18th-century Europe, the epitome of irreligion was deism. According to Pew Research Center projections, the nonreligious, though temporarily increasing, will ultimately decline significantly by 2050 because of lower reproductive rates and ageing.
In 1993, the UN's human rights committee declared that article 18 of the International Covenant on Civil and Political Rights "protects theistic, non-theistic and atheistic beliefs, as well as the right not to profess any religion or belief." The committee further stated that "the freedom to have or to adopt a religion or belief necessarily entails the freedom to choose a religion or belief, including the right to replace one's current religion or belief with another or to adopt atheistic views." Signatories to the convention are barred from "the use of threat of physical force or penal sanctions to compel believers or non-believers" to recant their beliefs or convert.