16. For indeed human births involve a previous non-existence, because, as a first reason, all are born from those, all of whom formerly were not. For although each one who is born has his origin from one who has been, nevertheless that very parent, from whom he is born, was not before he was born. Again, as a second reason, he who is born, is born after that he was not, for time existed before he was born. For if he is born to-day, in the time which was yesterday, he was not; and he has come into a state of being from a state of not being; and our reason enforces that that which is born to-day did not exist yesterday. And so it remains that his birth, by virtue of which he is, took place after a state of non-existence; since necessarily today implies the previous existence of yesterday, so that it is true of it that there was a time when it was not. And these facts hold good of the origin of everything relating to man: all receive a beginning, previously to which they had not been: firstly, as we have explained, in respect of time, and then in respect of cause. And in respect of time indeed there is no doubt that things which now begin to be, formerly were not; and this is true also in respect of cause, since it is certain that their existence is not derived from a cause within themselves. For think over all the causes of beginnings, and direct your understanding to their antecedents: you will find that nothing began by self-causation, since nothing is born by the free act of the parent, but all things are created what they are through the power of God. Whence also it is a natural property of each class of things by virtue of actual heredity, that it once was not and then began to be, beginning after time began, and existing within time. And while all existing things have an origin later than that of time, their causes also, in their turn, were once nonexistent, being born from things which once were not. Even Adam, the first parent of the human race, was formed from the earth, which was made out of nothing, and after time, that is to say, after the heaven and earth, and the day and the sun, moon and stars, and he had no first beginning in being born, and began to be when he once had not been.