This bachelor thesis deals with the phenomenon of English deism at the turn of the 17th and 18th centuries from the perspective of its rejection of the authority of external revelation. Deism can be briefly defined as an attempt to base religion only on the internal revelation, i.e. the rational knowledge. This thesis firstly presents the historical circumstances of this movement; further it gives an analysis of the relation between internal and external revelation as offered in Matthew Tindal's Christianity as old as the creation (1730) External revelation, according to Tindal, should be subjected to the internal revelation, i. e. the rational knowledge. Tindal derives this view from the perfection of his Religion of Nature, to which nothi...