The doctrine that belief in a passive creator-God is entirely consistent with reason, without recourse to established religion or the supernatural. In its 18th-century heyday, deism was particularly associated with such philosophical writers as Francois Marie Arouet de Voltaire (1694-1778) and Jean Jacques Rousseau (1712-1778) (although similar thoughts had been expressed by other thinkers in earlier centuries).
In an age when scientific discoveries were encroaching further and further upon long-accepted biblical ideas of God’s intervention in the world, deist philosophers argued that man was master of his own fate, having been given responsibility for his own deeds by God after the supreme being had brought the universe into existence.
Since the creation of the world, the deists held, God had taken no direct active part in the world’s affairs. To fulfill his obligations to God man would have to rely upon the exercise of his own intellect.
However, such writers as Rousseau still referred to an ‘unknowable’ inner faith in God that defied scientific analysis. This ‘irrational’ faith has since been much mauled by philosophers who find it inconsistent with the deists’ desire to base their beliefs upon reason alone.
M Wiles, God’s Action in the World (London, 1986)