It's said by the late 1600s Deism was strong enough competition for Christianity that England felt constrained to pass laws banning Deists from holding office. One hundred years later it was acceptable to be a Deist and while probably not as many as claimed, there were Deists among the founders of the United States, and they found commonality with Christians in many areas. The French Enlightenment was closely associated with Deism, and while they believed in a god who created, he was not a personal god nor did he care for humanity beyond creating them and giving them intellect. It sounds much like Aristotle's Prime Mover, who created the movements of the material realm and moved on. Isaac Newton supplied support to the Deists in posing the argument that we can assume and intelligence who designed the order and beauty of the world, and others who called themselves Christians supported the idea that man's intellect and reason were inseparably tied to Christianity. The emphasis on rationalism in the church led to a cold and distant religion, the type of which Søren Kierkegaard rebelled against and elevated the importance of individual experience.
René Descartes, who falls in the Rationalist camp, emphasized man's reason as superior and sided with Thomas Aquinas in saying that man could come to a secure knowledge of his own existence and that of God without the aid of anything other than reason. When Isaac Newton became the President of the Royal Society (a British science society), he decided theological discussions weren't helpful to science and banned apologetic stucy in the Fellow's scientific writing. Empiricism, in contrast to the Rationalists who acknowledged a place for god, sided wholly with Democritus in denying the existance of any a priori knowledge or god, stating that man's ideas were his alone, based on experience and observation. Bentham and Mill were advocates of these ideas, and their variation was called Utilitarianism, where actions producing the most good were morally right. Their definition of "good" was whatever brings pleasure—exactly Democritus' definition.
The Enlightenment is often placed as the begininng of the pendulum swings between cold rationalism to hot emotionalism, and artistically we find the Classical movement followed by the Romantic movement with a conflict between the cold, studied, polish of a Classical approach and the hot color and brushwork of the Romantic era. From here on to the present each style has rebelled against those styles before it in an attempt to "evolve" into something that has not existed before. In the Present, however, Postmodern ecclecticism has made any era or style available as legitimate, but we'll look at that later.
