Given the need to explain an explosion of a flour mill, assuming a purely Aristotelian paradigm, what concepts could be used to explain the mill's destruction?

This question is to help more accurately simulate and explore an academic's view of the world in the 13th century. How would they explain the idea of an explosion?

Looking at the History of Shockwaves, Explosions, and Impact, we see that firedamp explosions aren't really explored until the 13th century. Which suggests that the only intentional explosions possible were steam explosions, and they likely occurred in a different category than volcanism or flour mill dust explosions 1. There also seems to be no discussion of alcoholic vapour explosions.

Clearly, something can be gotten around by explaining after the fact of the love of the warm and moist particles for movement and expansion, and that "clearly" the particles were the result of a change in substance. And then someone would argue that instead of a change in substance it was a change in quality, as the warm and moist particles displaced the cold and dry particles.

That whole explanation begs the question of an appropriate category for concept "detonation" that existed without conception of momentum and the physics of expanding gasses; thus, my question.

1 The earliest recorded account of a flour mill explosion is in the 18th century. With that said, the notes on the flour mill explosion suggest that the explanation given then was due to "fermentation."

  • is there any historical evidence of explosions in Aristotles time? May 11, 2013 at 16:36
  • Not that I could find, but there are natural sources of explosions and accidental explosions that could certainly have occured. It is an open question if they were studied however. May 11, 2013 at 23:43
  • The ancient Greek atomists came up with a theory which in qualitative terms is roughly equivalent to 19C atomism. I could see them explaining an explosion as atoms moving away from each other at great speed. I do not know whether they did. Lucretious in his De Rerum Natura (On the Nature of things) may have something relevant as he purports to explain natural phenomena on the basis of a materialist philosophy including atomism. Epicurus may have something in his writings on atomism. I'm not sure what Aristotles position was on Atomism. He may have wanted to refute them. May 12, 2013 at 1:13
  • 1
    My intuition tells me that an explosion is incapable of being represented in Aristotelian physics for similar reasons as why Aristotelian physics doesn't permit projectile motion. Even early commentators on Aristotle's works recognized that his attempt at a resolution is clearly fallacious. See is.physics.kent.edu/7ideas_ebl/idea2/idea2/node3.html
    – David H
    May 12, 2013 at 6:42
  • To amplify the background, I'm running a game of Ars Magica where we are trying to fully imagine/instantiate the Aristotelian paradigm. My intention is to have an explosion occur, which begs the question of what the nature of an explosion is in a world without momentum. May 12, 2013 at 6:47

1 Answer 1


The closest concept in the Aristotelian paradigm is the idea of Thunder.

According to History of Shock waves, Explosions and Impact by Krehl, p 187, Aristotle had a surprisingly sophisticated conception of percussion:

"All sounds are produced by the meeting of bodies or of the air with bodies, because the air is set in motion in the same way in which, in other cases, bodies are moved, whether by contraction or expansion or compression, or again when it clashes together by an impact from the breath or from the strings of musical instruments (On things heard). ... Sound is heard in both in air and in water. What is required for the produciton of sound is an impact of two solids against one another and against their air. The latter condition is satisfied when the air impinged upon does not retreat from before the blow". (On the Soul)

Krehl continues by explaining that: "Addressing the action of intense sound waves (i.e. wak shock waves), he says "If the moving bodies are so great, and the sound whihc penetrates to us is proportion to their size, that sound must reach us with an intensity many times that of thunder, and the force of its action must be immense. (On the heavens)"

Thus, the fundamental idea of "the shock wave" exists in the Aristotelian paradigm, with earthquakes and volcanism being exhalations of air and moisture from the earth.

Extraploating both the ideas of shock waves and trapped pockets of air and fire, the same standards can be applied to a flour mill. Either

a. the mill was above a pocket of this trapped air and fire

b. that alteration occurred in the substance of flour while milling it, and this unusual alteration caused these self-same pockets to attempt to escape the confined "dry-cold" particles constituting the majority of the flour. Thus, the air and fire escape, carrying some of the dust with them, and make a noise like thunder as the flour meets the walls of the mill.

Therefore, An explosion is a thunderclap of great force and effect, generated not in the clouds, but nearby on the ground. The thunderclap is generated as particles seek their proper place and are constrained from that meeting.


Krehl, P. History of Shock Waves, Explosions and Impact: A chronological and Biographical Reference Springer, Berlin, p. 125-128

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