30 Phil, Chapter 28: Kant and Kantianism
The German philosopher Immanuel Kant (22 April 1724 – 12 February 1804) was a central figure of the Enlightenment which put reason as the tool of choice when discussing God, nature, and humanity. 
Some of my favorite translated quotes include:

• All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.
• Nothing is divine but what is agreeable to reason.
• We can judge the heart of a man by his treatment of animals.
• It is beyond a doubt that all our knowledge begins with experience.