Introduction [excerpt] This essay traces the diminishing visibility of Aristotle's qualitative physics in Western Europe from the Middle Ages to the modern era, examining various interpretations offered by major thinkers during this time period. Over this stage in history Aristotle's qualitative physics as a visible theory, one that is able to explain the motion of bodies in two realms, the earth and the heavens, is enervated until it is eventually overthrown and replaced by a single quantitative theory...