classic escape from the logical problem posed by Parmenides by distinguishing things that are matter and things that are space. In this scenario, space is not "nothing" but, rather, a receptacle in which objects of matter can be placed. The true void (as "nothing") is different from "space" and is removed from consideration. This characterization of space reached its pinnacle with Isaac Newton who asserted the existence of absolute space. René Descartes, on the other hand, returned to a Parmenides-like argument of denying the existence of space. For Descartes, there was matter, and there was extension of matter leaving no room for the existence of "nothing". The idea that space can actually be empty was generally still not accepted by philosophers who invoked arguments similar to the plenum reasoning. Although Descartes views on this were challenged by Blaise Pascal, he declined to overturn the traditional belief, horror vacui, commonly stated as "nature abhors a vacuum". This remained so until Evangelista Torricelli invented the barometer in 1643 and showed that an empty space appeared if the mercury tube was turned upside down. This phenomenon being known as the Torricelli vacuum and the unit of vacuum pressure, the torr, being named after him. Even Torricelli's teacher, the famous Galileo Galilei had previously been unable to adequately explain the sucking action of a pump. John the Scot John the Scot, or Johannes Scotus Eriugena (c. 815–877) held many surprisingly heretical beliefs for the time he lived in for which no action appears ever to have been taken against him. His ideas mostly stem from, or are based on his work of translating pseudo-Dionysius. His beliefs are essentially pantheist and he classifies evil, amongst many other things, into not-being. This is done on the grounds that evil is the opposite of good, a quality of God, but God can have no opposite, since God is everything in the pantheist view of the world. Similarly, the idea that God created the world out of "nothing" is to be interpreted as meaning that the "nothing" here is synonymous with God. G. W. F. Hegel Georg Wilhelm Friedrich Hegel (1770–1831) is the philosopher who brought the dialectical method to a new pinnacle of development. According to Hegel in Science of Logic, the dialectical methods consists of three steps. First, a thesis is given, which can be any proposition in logic. Second, the antithesis of the thesis is