Deism, derived from the Latin word "deus" meaning "god", is a theological/philosophical position that combines the rejection of revelation and authority as a source of religious knowledge with the conclusion that reason and observation of the natural world are sufficient to determine the existence of a single creator of the universe.

Deistic thinking has existed since ancient times.

Among the Ancient Greeks, Heraclitus conceived of a logos, a supreme rational principle, and said the wisdom "by which all things are steered through all things" was "both willing and unwilling to be called Zeus (God)".

Plato envisaged God as a Demiurge or 'craftsman'.

Outside ancient Greece many other cultures have expressed views that resemble deism in some respects.

However, the word "deism", as it is understood today, is generally used to refer to the movement toward natural theology or freethinking that occurred in seventeenth-century Europe, and specifically in Britain.

Deism gains prominence among intellectuals during the Age of Enlightenment—especially in Britain, France, Germany and the United States—who, raised as Christians, believe in one God but become disenchanted with organized religion and notions such as the Trinity, Biblical inerrancy and the supernatural interpretation of events such as miracles.

Included in those influenced by its ideas are leaders of the American and French Revolutions.

Today, deism is considered to exist in two principal forms: classical and modern, where the classical view takes what is called a "cold" approach by asserting the non-intervention of deity in the natural behavior of the created universe, while the modern deist formulation can be either "warm" (citing an involved deity) or cold, non-interventionist creator.

These lead to many subdivisions of modern deism which tends, therefore, to serve as an overall category of belief.

Despite this classification of Deism today, classical Deists themselves rarely wrote or accepted that the Creator is a non-interventionist during the flowering of Deism in the sixteenth and seventeenth centuries; using straw man arguments, their theological critics attempted to force them into this position.