DEISM, the doctrine or belief of the deists. Deism, from Deus, God, is properly used to denote natural religion, as comprehending those truths which have a real foundation in reason and nature; and in this sense it is so far from being opposed to Christianity, that it is one great design of the gospel to illustrate and enforce it. Thus some of the deistical writers have affected to use it. But deism more commonly signifies that system of religion, relating both to doctrine and practice, which every man may discover for himself by the mere force of natural reason, independently of all revelation, and exclusive of it; and this religion, Dr Tindal and others pretend, is so perfect, as to be incapable of receiving any addition or improvement even from divine revelation.