5 Paul, indeed, observing that there are in Greek philosophy certain things not to be lightly esteemed, which are plausible in the eyes of the many, but which represent falsehood as truth, says with regard to such: “Beware lest any man spoil you through philosophy and vain deceit, after the tradition of men, after the rudiments of the world, and not after Christ.” And seeing that there was a kind of greatness manifest in the words of the world's wisdom, he said that the words of the philosophers were “according to the rudiments of the world.” No man of sense, however, would say that those of Celsus were “according to the rudiments of the world.” Now those words, which contained some element of deceitfulness, the apostle named “vain deceit,” probably by way of distinction from a deceit that was not “vain;” and the prophet Jeremiah observing this, ventured to say to God, “O Lord, You have deceived me, and I was deceived; You are stronger than I, and hast prevailed.” But in the language of Celsus there seems to me to be no deceitfulness at all, not even that which is “vain;” such deceitfulness, viz., as is found in the language of those who have founded philosophical sects, and who have been endowed with no ordinary talent for such pursuits. And as no one would say that any ordinary error in geometrical demonstrations was intended to deceive, or would describe it for the sake of exercise in such matters; so those opinions which are to be styled “vain deceit,” and the “tradition of men,” and “according to the rudiments of the world,” must have some resemblance to the views of those who have been the founders of philosophical sects, (if such titles are to be appropriately applied to them).
6. After proceeding with this work as far as the place where Celsus introduces the Jew disputing with Jesus, I resolved to prefix this preface to the beginning (of the treatise), in order that the reader of our reply to Celsus might fall in with it first, and see that this book has been composed not for those who are thorough believers, but for such as are either wholly unacquainted with the Christian faith, or for those who, as the apostle terms them, are “weak in the faith;” regarding whom he says, “Receive him that is weak in the faith.” And this preface must be my apology for beginning my answer to Celsus on one plan, and carrying it on on another. For my first intention was to indicate his principal objections, and then briefly the answers that were returned to them, and subsequently to make a systematic treatise of the whole discourse. But afterwards, circumstances themselves suggested to me that I should be economical of my time, and that, satisfied with what I had already stated at the commencement, I should in the following part grapple closely, to the best of my ability, with the charges of Celsus. I have therefore to ask indulgence for those portions which follow the preface towards the beginning of the book. And if you are not impressed by the powerful arguments which succeed, then, asking similar indulgence also with respect to them, I refer you, if you still desire an argumentative solution of the objections of Celsus, to those men who are wiser than myself, and who are able by words and treatises to overthrow the charges which he brings against us. But better is the man who, although meeting with the work of Celsus, needs no answer to it at all, but who despises all its contents, since they are contemned, and with good reason, by every believer in Christ, through the Spirit that is in him.
Source: Against Celsus (New Advent)