291 a lot of fire in air will be heavier than a little bit: for fire in air has no heaviness.But, one should argue this way: Fire, considered absolutely, has heaviness: hence, where fire has heaviness, a lot of fire will have a lot of heaviness; and where fire has lightness, as in air, there a lot of fire will have a lot of lightness, and a little bit, will have little.It is thus certain that there is an error of Aristotle in arguing. Secondly, what he asserts is false, namely, that a lot of fire goes up more swiftly than a little bit, or that a lot earth goes down faster than a little bit; as we have demonstrated above {1}.
Thirdly, he argues: If fire has heaviness, then a lot of fire will be heavier than a little bit of air; which he assumes to be the greatest absurdity, as if we were saying, If earth has a certain lightness, a certain part of earth will be lighter than a certain part of water: which, says he, is false, because we see, that any part of earth goes down in water, and any portion of fire in air is carried upward.Now this assuredly is a weaker argument than all the others: who is so stupid as not to believe that a lot of water is heavier than a little bit of earth, and a lot of air than a little bit of water, and a lot of fire than a little bit of air?And what Aristotle says does not stand in the way: We see earth go down in water.For, when he says this, he is not self-consistent: that is, when we say that water has heaviness, we are not saying that it has heaviness in its own region, where, as has been demonstrated, it has neither heaviness nor lightness; but we are saying that, a lot of water is heavier than a little bit of earth in a place where water also has heaviness, as, for instance, in air.For if this way of arguing were valid, I could also conclude that a little bit of lead is heavier than a very large beam, because lead goes down in water, whereas the beam will not: but what happens is that a little bit of lead is heavier than a beam in a place where the beam has no heaviness; but if we want to talk of the heaviness of the beam, the beam must be assumed to be in a place where it has heaviness.Similarly, when he says, Any particle of water in air goes down, hence as much air as one wants is lighter than a particle of water; this will be true in a place, where air has no heaviness, but water has: but this will not be to talk of absolute heaviness, as we are doing here.For if we assume a lot of air in a place where air also exerts weight, as in fire or in a void, there surely it will be heavier than a little bit of water. Let it not be concluded, Hence it will go down faster: for someone who concluded thus would