The scientific revolution was born in the mid-1500s. Modern science was born during this time when anything as simple as thermometers and telescopes was one of the most amazing things ever seen or heard. New scientific discoveries that radically changed the way humans understood the world occurred in this period through the late 1700s. Paradigm shifts were happening in every direction possible. A paradigm shift is a change in basic assumptions that is corrected and causes thoughts to shift to another assumption. The thoughts of the old theories were destroyed and replaced by modernized and corrected ones. Every scientist at that time was attempting to create a paradigm shift that would affect the world drastically. One of those scientists was Joseph Priestley. This chemist and philosopher discovered one of the greatest things in the world. He discovered oxygen or, in other words, deflogistic air. Before the 1700s, people believed in the phlogiston theory, which states that we breathe to eliminate phlogiston, an odorless, colorless substance that is absorbed into the air after combustion. In 1774, a new theory replaced it. The theory was called deflogistic or, in other words, oxygen theory. Joseph Priestley discovered that we do not breathe to emit phlogiston but we breathe to absorb oxygen which helps us in cellular activities and to release carbon dioxide (phlogiston theory). After Priestley discovers this new gas, he begins to feel confused with his discovery and goes to France to meet his fellow scientist and together they discuss this new theory of deflogistic air. He repeated his experiments and proved to Antoine, the scientist he met, that the theory was true, even though Priestley disagreed... half of the paper... Tannica, Inc., 2014. Web . May 15, 2014. .Kingston, Elizabeth. "Encyclopedia of Philosophy on the Internet". Priestley, Joseph. Np, nd Web.18 May 2014. “Oxygen, an Element in Air: Joseph Priestley.” Oxygen, an element in the air: Joseph Priestley.NP, nd Web. May 14, 2014.Schlager, Neil and Josh Lauer. "Life sciences and medicine". Science and its times: understanding the social meaning of scientific discovery. Detroit: Gale Group, 2000-2001. 192. Print.Schofield, Robert E. Joseph Priestley, natural philosopher. Iowa: Bull. History. Chem., 2005.Print."Science and Faith." Chapter 1: What can we know and how do we know it?. Np, ndWeb. May 13th 2014.