Since, however, every thing that changes is changed from something into something, it is necessary that what is changed, when it is first changed, should be in that into which it is changed: for that which changes proceeds from that from which it changes, or leaves it; and either to change and to leave are the same, or the latter is consequent to the former, and the having left to the being changed; for each subsists similarly with reference to each. Since, therefore, of mutations, one is that which is according to contradiction; when a thing is changed from non-being into being, it leaves non-being. It will be, therefore, in being: for it is necessary that every thing should either be or not be. Hence, it is evident, that in the mutation according to contradiction, that which is changed will be in that into which it is changed. But if it is so in this mutation, it will likewise take place in others: for the thing is similar in one and in others. Again, this will be evident to those who consider the affair more particularly; if it is necessary that what is changed should be somewhere, or in something: for since it leaves that from which it is changed, and it is necessary that it should be somewhere, it will be either in this, or in another. If, therefore, that which is changed into B, is in another, as for instance in C, again it will change from C into B; for it did not adhere to B; because the mutation is continued. So that what is changed when it is changed, changes into that into which it is changed. But this is impossible. Hence it is necessary that what is changed, should be in that into which it is changed. It is evident, therefore, that what is made will then be when it is made; and that what is corrupted, will not be when it is corrupted: for this has been universally asserted of every mutation, and is especially evident in the mutation according to contradiction. That what is changed, therefore, is, when it is first changed, in that into which is changed, is evident.
