In the first place it is held by most of the early Christian authors, and explicitly stated by many of them, that the idea of the existence of God is innate in man as a "natural opinion." We have already noticed the doctrine of πρόληψις advanced by Epicurus, and the somewhat similar position assumed by Philo, and we are not surprised to find that this idea took a strong hold on the devout minds of the early Christians. Thus St. Justin Martyr states that "the appellation 'God' is not a name, but _an opinion_ (προσαγόρευμα) _planted in the nature of man_ of a thing that can hardly be explained,"[34] and makes one of his discussions conclude that souls "can perceive (νοεῖν) that God exists."[35] St. Clement of Alexandria goes even further and affirms that "the Father, then, and Maker of all things is apprehended by all things, agreeably to all, _by innate power and without teaching_."[36] Tertullian thinks that "the soul was before prophecy. From the beginning the knowledge of God is the dowry (_dos_) of the soul,"[37] and among the "things known even by nature" is "the knowledge of our God" which is "possessed by all,"[38] so that he could write a treatise, _De Testimonio Animæ_, and exclaim, "O noble testimony of the soul by nature Christian."[39] Origen speaks of "the uncorrupted idea of Him which is implanted in the human mind,"[40] and St. Cyprian makes this knowledge so plain that "this is the very height of sinfulness to refuse to acknowledge Him whom you cannot but know."[41] Arnobius, too, in a passage in which much allowance must be made for rhetorical fervor, exclaims, "Is there any human being who has not entered on the first day of his life with an idea of that Great Head? In whom has it not been implanted by nature, on whom has it not been impressed, aye, stamped almost in his mother's womb even, in whom is there not a native instinct, that He is King and Lord, the ruler of all things that be? In fine, if the dumb animals even could stammer forth their thoughts, if they were able to use our languages; nay, if trees, if the clods of the earth, if stones dominated by vital perceptions were able to produce vocal sounds, and to utter articulate speech, would they not in that case, with nature as their guide and teacher, in the faith of uncorrupted innocence, both feel that there is a God, and proclaim that He alone is Lord of all?"[42] Such language as this last example is, of course, the exclamation of the orator rather than the deliberate judgment of the philosopher, but taken in connection with the other passages cited it will indicate how strong a hold this conviction had on the Fathers, and will anticipate, to some extent, what we shall have to say later as to the use of the _Argumentum e Consensu Gentium_.