The main ideas we associate with the Enlightenment. During the Enlightenment people thought they could do certain things. They thought that human reasoning could be used to discover truths about the world, religion, and politics to make peoples lives better. Another idea was skepticism about received wisdom. Everything had to be tested and proven correct.

According to Wikipedia “**Leonhard Euler** was a Swiss mathematician, physicist, astronomer, geographer, logician, and engineer who founded the studies of graph theory and topology and made pioneering and influential discoveries in many other branches of mathematics such as analytic number theory, complex analysis, and infinitesimal calculus.” According to csmonitor.com, “Euler was the first to introduce the notation for a function f(x). He also popularized the use of the Greek letter π to denote the ratio of a circle’s circumference to its diameter. Euler also made contributions in the fields of number theory, graph theory, logic, and applied mathematics.”

The Ptolemaic-Aristotelian view of the universe. According to Vassar College, “In this cosmology, the earth does not revolve around anything else or rotate around its own axis. It is surrounded by ten concentric spheres made of a perfectly transparent substance known as “quintessence.” These spheres revolve around the earth, carrying the other celestial bodies.” This is very different from what we believe today. We believe that the sun is the center of our universe and eight planets, with their moon revolve around the sun.