Through new translations of Aristotle’s works, in the thirteenth century the University of Paris became embroiled in the middle of an enormous scandal: the professors were teaching things considered dangerous to the teachings of the Roman Catholic Church. This caused a crisis in Europe, and the Roman Catholic Church brought in the smartest man in Europe to help out: Thomas Aquinas. One of the most important works of the Middle Ages, the Summa Theologica acknowledged the role of rational thought in observations of the universe. From the Summa Theologica, scholars such as Francis Bacon, Robert Grosseteste, and Theodoric of Freiburg were able to apply observation to the natural world, and developed the modern scientific method.
Of course, this new line of thought is not without its hazards; now that we know that the universe cannot be explained in simple, reductionistic terms, the scientific method, while still yielding valuable results, is limited in what it can tell us. However, without the scientific method, most of the inventions and advances of the last seven hundred years would not have come about: in short, we would not have the modern world without these medieval philosophers, who taught us to view the world rationally.
So the next time you use an appliance, drive a car, take a prescription drug, or do anything that people could not do a hundred years ago, I hope you will take a moment to thank those medieval philosophers. Thomas Aquinas is the scholar who made all these advances possible for us.