B. About the Production of Infernal Fire

46. About the first point: If the fire is posited as created, it is necessary to posit that an equal amount of some other corruptible body is annihilated; or that in the whole corporeal or incorporeal substance a compressing occurs that corresponds to the quantity of this created fire; or it is necessary to posit that this created fire is together with some other body. Also, if it is posited as created, and consequently created from some other thicker body (for fire is the most subtle body among corruptible bodies), it is necessary to say that some other corruptible body is as much compressed as the body from which it is generated is rarer, or that, conversely, a rarer body is converted into a denser one proportionate to this quantity.

47. Therefore, if it were generated from air, either air would have to be converted into water, or water into earth, in as great proportion as would cover the spreading of the generated fire.

48. The thing is plain in an example: For let it be that the whole sphere of air be divided into ten parts, from one of which the fire is generated; and the fire has ten parts each one of which is equal to that [one part of air] from which the whole fire is generated - where will the nine parts [of the remaining air] have their location? Either two bodies must be together, or they must be compressed (or other bodies standing around must be) until they do not fill up the place of nine parts [of air]. But if this happen by the conversion of these nine parts into water, a place for the converted fire will be obtained even though there be no compression of anything else; because those nine [parts of air] do not generate one part of water, but almost do,If ten parts of air are assumed to produce, on conversion, one part of water, then nine parts of air will produce, on conversion, something less than one part of water. ³³ which [one part of water], along with nine previously generated parts of fire (one of the parts is located in the place of the air corrupted into fire), fill the whole place of the ten parts of air. And then there would be a flood of water along with the flaming of the fire, though not in as great a quantity as is the flaming of the fire; for the water would exceed the preexisting water in a part that is a tenth of the generated new fire.Scotus follows the prevailing view, derived from philosophical tradition, that the elements of the physical world are the four of earth, water, air, and fire, with earth being the grossest and fire the subtlest, and with earth at the center and the others round it (in progressive order of subtlety) at different levels or spheres. His example is complex, nevertheless, in expression, but it seems to amount to the following. The whole of the existing air is divided into ten parts and one of these parts is converted into fire. The converted fire itself has ten parts and, being less dense than air, these ten parts together fill up the space of all ten parts of air even though only one part of air was used to generate the ten parts of fire. So, there are nine parts of air remaining that have no place left to exist in. Either then they occupy the same place as the generated fire (so that more than one body is in the same place), or the air is compressed, or other surrounding bodies are, until the nine parts of air no longer fill up the same place as before. If this compression happens by conversion of the nine parts of air into water, and this water fills the same place as one part of air or a bit less (and so the same as one part of fire or a bit less), there will be a flood of water that exceeds any pre-existing water by a part that is equivalent to a tenth part, or a bit less, of the generated fire. The oddity here is that this new water will be in the same place as a tenth part, or almost, of the fire. For the fire converted from one part of air occupies the place of all ten parts of air, so that the nine parts of air not converted into fire and now assumed to be converted into one part or less of water (and so compressed into the equivalent of the place previously occupied by one part or less of air) must occupy the place occupied by one part or less of fire. The flood will indeed be a flood. ³⁴