The Philosophy of Roger Bacon

Everything accidental is reduced to something essential, which does not happen except through itself; and there would be another cause from the Author referring to God or the Prime Mover in the first chapter. And matter and matter, and so on to infinity. Therefore, as they concede, every quality goes back to itself through itself and to what is essential. Therefore, circular motion will be innate in some body that is divided according to its species from a body that moves in a straight line The author argues that if straight motion belongs to the four earthly elements, circular motion must belong to a fundamentally different kind of substance: the ether. Likewise, no accident is innate, as was shown previously through the fourth book in the eighth [book] of the Philosopher Aristotle. However, circular motion can be separated so that it remains in the heavens throughout time. Wherefore, it will not be merely an accident; and if it is an accident to one body, it will be essential to another—to another, I say, according to its species. Likewise, a bright body is worthy through a straight [line] and a brighter motion than a straight one, which is more perfect according to the first [book] on nature by the Philosopher. Wherefore, if a straight motion and a mode of motion innate to the world [exists], it is necessary that there be a body whose innate mode is circular motion, and which receives this motion from its own power. But that it is round is of perfect reason: it is plain that a straight body is capable of being led [into a circle] if it becomes straight and for this reason... it is a work of reason, as Averroes says in the second [book]. The whole reasoning with your declaration is proved by Aristotle and Averroes; and although it is supposed here that every straight body would be infinite, the reason is easily declared and proved from what follows, as is evident. It is declared that it cannot be heavy nor light; no body can be infinite, and he will declare this in the proper time concerning On the Heavens and the World Aristotle's De Celo et Mundo. And upon this another reason is founded, since as Averroes says here, a body

this reason

Note that he seems to be expounding on Averroes here.

of straight divisions referring to the linear paths of the four elements: earth, water, air, fire this reason? pertains to the continuum itself, which cannot be a round matter. Because a flame from itself is [centered] in its own place, it would grow heavy, and its straightness would grow heavy. Nor [can it be] through rarefaction?, because it was proved before that a vacuum cannot exist

In the beginning they do not have that.

...as a round body, because it would be possible for that body by its own nature to be moved upward or downward; if heavy, it would leave a vacuum in its retreat, because where the body was, there would be [nothing]. And Averroes supposes from where it is demonstrated that a straight body is not in matter; therefore it is necessary that some straight body be a round and circular body. But otherwise, through another [argument] from the mind of Averroes, argue regarding motion: for a straight body is gravi-valle heavy/subject to gravity and corruptible in part as in the whole, as Averroes [says].