The Philosophy of Roger Bacon

...and the Metaphysics original: "meth"; referring to Aristotle's "Metaphysics," a foundational text for medieval science; concerning which it is said in the same work that things of this kind, which are placed under the same genus, are most distant from one another correct and thus either regarding species under one genus. And if contrariety In Aristotelian logic, "contraries" are opposites within the same category (like black and white) that allow for change; the author is arguing whether the heavens have such opposites. can well exist between the heaven and [other bodies] mutually... what is heaven, which is called the heaven and the sky, and to it all things are reduced, both the heavens and [the world]. There is no duality of opposites there illic? in their genera and through... in [the text]. Another kind is contrariety [taken] accurately and strictly over matter, which everywhere [results in] being born and in corruption original: "corruptione"; the process of decaying or passing out of existence... they are natured to be generated from one another. This follows, therefore, the earth and that which is heaven and another. Here the heaven does not have [this], which is neither an element nor a certain [earthly] body, because it is ingenerable unable to be created or born from something else and incorruptible incapable of decaying or dying.

¶ If it is said that for straight motion original: "motui recto"; motion in a straight line, which Aristotle assigned to the four elements: earth and water (down), air and fire (up) there is a contrary by natural rest and not by circular [motion]... if for circular motion original: "motui arculari"; a variant for circular motion, which was considered "perfect" and eternal there is [a contrary] mutually... natural motion... which is not straight... a certain body [is]. And if it is solved through [logic] in which however much could be in circular motion; and this [induction] the Apostle original: "apostolus"; while this often refers to St. Paul, in the context of medieval science, it may be a scribal error for "Philosophus" (Aristotle), or an attempt to harmonize scripture with physics. introduces, as you see... to exclude a third [body]... because circular motion cannot be [contrary]... as straight [is to] straight, but these two are [under] one contrariety.

¶ Also, straight [motion] is toward the center original: "medium"; the center of the earth, which was the center of the universe in this model or away from the center. And [circular motion] is around the center, which is not contrary to either of the aforementioned [motions]... nevertheless, [motion] toward the center is entirely [contrary] to that which is away from the center, because they are from contrary terms... the center does not have contrariety, although it may have a certain duality.

¶ But if it is said that in circular motion there are smaller parts and [they tend] toward the same thing, just as anything in straight motion [does]. And it is said... in the world... why there is one contrariety in them. But in straight motion... none of these motions can be [contraries] and because they are not smaller parts and semicircles. ¶ For the greatest distance between two terms is designated by a single line. And to have between two terms...