The major formative influences on the philosophes of the 18th century were the revolutionary thinkers of the 17th century. These thinkers, both in sciences and in other areas, had a major impact on the thinking of the philosophes.
The philosophes wanted to apply reason and rationality to improve society. Therefore, it is not surprising that they were influenced by thinkers who pioneered this type of thought. Very important among these thinkers were scientists like Sir Isaac Newton. The philosophes looked to scientists like Newton and philosophers like John Locke as examples of how to use reason and rationality to investigate the world. These kinds of thinkers were the major influence on the philosophes.