Atheism is defined as a lack of belief in supreme beings. An atheist may be a person who actively repudiates religion or someone who simply does not believe in a god.
Atheism is often confused with or conflated with agnosticism, but the two are fundamentally different. Agnosticism is the belief that humans are not capable of knowing whether or not there is a god whereas atheism is based on the definite proposition that no god exists. Atheism is also distinct from deism, a theistic belief that rejects the divine revelations professed by organized religions.
The term atheism comes from the Greek language. It is a combination of theos, meaning “gods”, and the prefix a, meaning “not” or “without”. For most of history, it was applied pejoratively to individuals who strayed from the majority religion. Few people would openly call themselves atheists for fear of religious persecution, which often included the death penalty.
Nevertheless, atheistic ideas have been expressed by philosophers and scientists throughout history. Greek philosophers such as Democritus, Critias, and Prodicus made statements that are interpreted as denials of a supreme being’s existence. Some branches of ancient Indian philosophy are atheistic. During the Middle Ages, the Islamic world produced a few atheistic thinkers as well such as Muhammad al Warraq, Ibn al-Rawandi, and Al-Razi.
In recent decades, an active atheist movement – sometimes called “New Atheism” – has emerged that aims to reduce the influence of religion in public life and promote reason and skepticism as guiding principles for society. This movement has centered around the works of philosophers such as Richard Dawkins, Sam Harris, Daniel Dennett, and the late Christopher Hitchens.
Atheists may subscribe to a variety of ethical philosophies that do not involve divine commands. These may be rooted in biology, utility, or virtue. Some atheists dispute that a person is truly moral if they are acting out of fear of divine retribution instead of ethical principles.
Atheists are the minority in most countries, but the highest concentrations are found in Europe, Canada, Australia, and New Zealand. Countries with the fewest atheists are in Africa, the Middle East, and South America. Some statistics show that more people in developed countries are becoming atheists, but the worldwide percentage of atheists may be decreasing due to low birth rates in heavily atheist countries and high birth rates in strongly religious countries. It should be kept in mind that actual demographics are difficult to come by because of the prevalent social stigma against atheism.