a cause stands on the same ground. For, supposing that nothing exists relatively to which a cause can be spoken of; then, as there is no production, or destruction, or anything of that sort, there can likewise be no cause. However, let us admit that there are such things as causes. In that case then, either a body must be the cause of a body, or that which is incorporeal must be the cause of that which is incorporeal. Now, neither of these cases is possible, therefore, there is no such thing as cause. In fact, one body cannot be the cause of another body, since both bodies must have the same nature; and if it be said that one is the cause, inasmuch as it is a body, then the other must be a cause for the same reason. And in that case one would have two reciprocal causes; two agents without any passive subject.
Again, one incorporeal thing cannot be the cause