Bern, Burgerbibliothek, Cod. 402

This itself is marvelous, and original: "εἰ δὲ μὴ θ' ὑπὸ καὶ διὰ τοῦτον ἡ θερμότης ἐκεῖ-" if heat is not by and through this; it is evident that both fire and the sun are in an underlying subject as heat. This, again, is absurd, for the arche first principle and the primary thing would be in an underlying subject. For heat and its power is the principle; it is common and extends further, and is more authoritative concerning alteration and natural generation. Fire, as it were, is generative of itself, but destructive as in the case of all other things. Hence, it is clear that the nature of fire and heat is something different. But now, it is said that in the earthy and airy realms, caustic heat is generated from dry anathumiasis exhalation/fume. It moves, but not for a long time in liquids under the influence of air. Except, as we speak of flesh, we say [this], but these things seem to lead us to a greater investigation of the underlying subjects, or it seeks the first causes, for it appears that in this way they take the hot and the cold as if they were passions of certain things and not principles and powers; at the same time, the nature of the so-called simples is something mixed and existing in relation to one another. For just as it is not possible for fire to exist without air, or some liquid and earthy fire thing, so neither is the liquid without fire, nor the earth without liquid. A sign of this is that the earth solidifies through compression, or it would not remain if the liquid were completely and entirely absent. Therefore, all things appear common and in need of determination. How is one to speak of simple things? The things prior to these, when mixed, have greater questions, as we said. That, however, is clear from all, that the nature of fire has its own and most numerous powers, just as was said at the beginning of the arguments.