The universe is seen as a vast and complex machine, one whose laws and functions it is man's task and privilege to discover and control. The government encourages and finances scientific pursuit, believing it will contribute to the general welfare. Astronomy, chemistry, biology, and many other sciences mature and make great advances through the 18 th century. The philosophical revolution is just as dramatic. The very nature and role of reason is radically redefined by the Enlightenment.
Philosophy comes to be identified more and more with analysis and critical thinking.
As this happens, serious doubts are raised not only about the value but even the possibility of religious or metaphysical knowledge. Philosophical reason is no longer defined by its results, meaning an intellectual heritage, a body of truths to be learned. This is a cause for excitement and optimism, because the enlightenment thinkers believe that human suffering arises mainly from ignorance. Thus, once reason casts its light into the darkness, it will bring not only truth but happiness. Of course, there is a cost.