Discrimination against atheists, both at present and historically, includes the persecution of those identifying themselves or labeled by others as atheists, as well as the discrimination against them. Discrimination against atheists may also refer to and comprise the negative attitudes towards, prejudice, hostility, hatred, fear, and/or intolerance towards atheists and/or atheism. As atheism can be defined in various ways, those discriminated against or persecuted on the grounds of being atheists might not have been considered as such in a different time or place. As of 2015, 19 countries punish their citizens for apostasy, and in 13 of those countries it is punishable by death.
In some Islamic countries, atheists face persecution and severe penalties such as the withdrawal of legal status or, in the case of apostasy, capital punishment.
Sometimes such discrimination is called atheophobia,atheistophobia,anti-atheist discrimination, or anti-atheist sentiment.
Scholars have argued that some small underdeveloped glimpses of atheism existed in the ancient world, though not in a modern sense because people had not developed a language for nonbelief; theistic beliefs in 5th Century BC Greece were not very active in public life the way they are in the modern world, and polytheism made it difficult to centralize beliefs of any region or culture.Lucien Febvre has referred to the "unthinkability" of atheism in its strongest sense before the sixteenth century, because of the "deep religiosity" of that era. Karen Armstrong has concurred, writing "from birth and baptism to death and burial in the churchyard, religion dominated the life of every single man and woman. Every activity of the day, which was punctuated by church bells summoning the faithful to prayer, was saturated with religious beliefs and institutions: they dominated professional and public life—even the guilds and the universities were religious organizations. ... Even if an exceptional man could have achieved the objectivity necessary to question the nature of religion and the existence of God, he would have found no support in either the philosophy or the science of his time." As governmental authority rested on the notion of divine right, it was threatened by those who denied the existence of the local god. Those labeled as atheist, including early Christians and Muslims, were as a result targeted for legal persecution.