The Pelagian bonum et malum quo nos laudabiles vel vituperabiles sumus (good and evil by which we are praiseworthy or blameworthy), in other words, the fruits of the tree of the knowledge of good and evil, became the spiritual nourishment par excellence, the "one thing necessary," for the medieval philosophers as it had been for the Greeks. "The greatest good of man is to discourse daily about virtue," says Socrates in Plato's Apology. And we shall hardly be mistaken if we see in this the articulus stantis et cadentis of the Greek wisdom. Gilson is certainly right when he urges us not to put too much trust in what is customarily called "the perfect serenity (sérénité) of the Greek world." Nietzsche was the first to discover many things which no one had suspected. He saw, we recall, and showed us in Socrates the décadent, the fallen man. And it was precisely in what the Delphic oracle regarded as his greatest merit and in what Socrates himself saw his difference from other men that his fall, in Nietzsche's eyes, consisted: Socrates esteemed and taught others to esteem in life only the praises of the good and feared and taught others to fear only the blame of the same good.
All of the Greek wisdom is based on this principle. The dialectic discovered by the Greeks had as its essential task to denigrate the fruits of the tree of life, to convince man of their uselessness and nothingness. The basic objection that the Greeks, as well as St. Augustine and later the Scholastics, made to the fruits of the tree of life was that these fruits are not in our power: the possibility of obtaining them, and still more of preserving them, does not depend on us. From this derives the very significant distinction made by the Stoics between "what is in our power" and "what is not in our power," and their no less famous doctrine that man must seek only that which is in his power, all the rest being relegated into the domain of the "indifferent."
We find in Epictetus the confession that the beginning of philosophy is the knowledge that man has of his own impotence before Necessity. To escape from the Necessity which rules in this world, there is no other means of salvation, the Greeks believed, than to turn toward the intelligible world. It is there that the wise man seeks a refuge against the sufferings, the horrors, the injustices of the real world. And since the intelligible world is accessible only to reason, to the spiritual vision, to the "eyes of the mind," the Greeks naturally put all their hope in reason and regarded it as the highest part of man. Furthermore, they had irrefutable arguments for doing so: man is a rational animal. Reason is his differentia specifica which distinguishes him from the genus of animals in general and, consequently, it is in this that his essence as man consists. For man to live according to nature, taught the Stoics, means to live according to reason.
The Scholastic philosophy joyfully received this truth, among so many others, from the hands of the Greeks without even taking the trouble to look at what Scripture said on the matter or, to put it better, prepared in advance not assuredly to reject, but to be silent about, or interpret, everything in the Bible that could not be harmonized with the wisdom of the Greeks. It read in St. Paul that the principal and essential thing for man resides neither in reason nor in knowledge. Knowledge makes man presumptuous, and all the gifts of knowledge are nothing without love. The philosophers of the Middle Ages spoke constantly of love - Gilson devotes a remarkable chapter to their doctrine of love - but, as we shall see, the Scholastics were also obliged to proceed to a purification, a catharsis, of the love of the Bible in order not to offend in any way the ancient ideal. In the medieval philosophers love is transformed into what Spinoza later called amor Dei intellectualis, so that Gilson's chapter could be applied quite as well to the philosophy of Spinoza as to that of the Middle Ages.
"When the so-called philosophers by chance speak what is true and corresponds to our faith, this is to be claimed for our use as from unjust possessors": so St. Augustine defined his attitude towards Greek philosophy. Yet, as we have already had occasion to become convinced, in fact it was the opposite that happened: the Greek truth was not verified by means of the biblical truth but the biblical by means of the Greek. When trying to reconcile the Platonism of St. Augustine and of Dionysus the Areopagite with his own doctrine, St. Thomas Aquinas wrote: "For the intellectual light itself which is in us is none other than a certain similarity through participation with the uncreated light in which the eternal truths are contained."  It is difficult not to recognize here the idea of "the separated reason, the only immortal and eternal thing," the intellectus separatus of Aristotle. St. Thomas, it is true, refers to the text (Psalms IV, 7.): "There be many that say, Who will show us any good? Lord, lift Thou up the light of Thy countenance upon us." He also quotes the well-known text of St. Paul, Romans I, 20. But these quotations precisely make clear the goal that the medieval philosophers set themselves when they sought "metaphysical principles" in the Bible.
By means of the method of analogy, the most risky of methods imaginable, medieval philosophy passed from the empirical truths that the intelligence discovers in experience to the eternal and unchangeable truths that it called "metaphysical." Now when we examine it closely, it appears that the method of analogy is very little distinguished from the method of discovery of truth employed by Socrates and which hid in itself a secret defect. As has already been indicated, the latter inevitably led the last of the great Greek philosophers, Plotinus, to a distrust of the very essence of Greek thought.
Socrates took for his point of departure what men ordinarily considered true and good; starting from this, he deduced that there is an eternal truth and an unchangeable good. He dealt always with men of action, practical men - smiths, carpenters, doctors, politicians, etc. He thus arrived at the conviction that the essence of the truth and the good consists in knowing the conditions in which man is born and in living in such a way as to submit to them and adapt one's activity to them. Up to this point he doubtless followed the right way. But when he concluded that the laws and conditions of human existence that he had observed reflected the truth an sich and that submission to these conditions was the good an sich, he committed a crying "leap into another realm." It is, indeed, just the contrary: the truth an sich and the good an sich cannot be perceived by him who, thanks to the conditions of his existence, finds himself placed in the necessity of "learning" and "adapting himself." The truth and the good live on a completely different level.
How little the biblical words "lift Thou up the light of Thy countenance upon us" resembles those rationes aeternae (eternal reasons) for which the medieval philosophy, hypnotized by the Greek wisdom, had exchanged them! Here again we are forced to remember the tree of knowledge and the tree of life. The tree of knowledge bore the eternal truths and the "good and evil by which we are praiseworthy and blameworthy," that is, worthy of the praise and blame of him who, with his "you will be like God" reduced the human soul to slavery. Can one imagine anything which less resembles the living God of biblical thought than the eternal truths, incapable of changing anything whatsoever that they bring to man, congealed, petrified and petrifying? It is true that the Scholastic philosophers could cite - and they did not fail to do so - "I am the Lord and I do not change."
But it is here that Gilson's comment is justified: our concepts fall to pieces when we try to introduce into them the content of the Bible. The immutability of God has nothing in common with the immutability of the eternal truths. The latter do not change because they have not the power to change; God does not change because, and insofar as, He does not wish to change and does not judge it good to do so. When Abraham, the father of faith, intercedes on behalf of Sodom and Gomorrah, God listens calmly, takes what he says into consideration and changes his decision. Of such examples one can find as many as one wishes in the Bible, and if one is not afraid of Aristotle and his "the poets lie," one would have to admit that the immutability of the biblical God has not even the most distant resemblance to that immutability which the Greek wisdom venerated, but even excludes it. Like the Sabbath, the immutability of which the Bible speaks exists for man and not man for the immutability. Immutability does not rule God, it serves Him, as do all the other truths which, insofar as they are created, possess only an executive power and only for as long as they are of some use.
All this clarifies, to a certain point, the relationship between the tree of knowledge and the fall of man. Enthralled by the tempter's words eritis scientes, Adam exchanged the freedom which determined his relationship to the Creator who hears and listens for a dependence on the indifferent and impersonal truths which do not hear and do not listen to anything and automatically actualize the power which they have seized. That is why it is incorrect to speak of the relationship of man to God as a relationship of dependence: the relationship of man to God is freedom. And it was precisely this that Dostoevsky had in mind when, face to face with "two times two makes four," with "the stone wall" and with other "impossibilities," he demanded that his "caprice" be guaranteed to him. He choked "in a universe where evil is a given fact whose reality cannot be denied," and he felt the necessity of submitting to the "given" as the consequence of the original sin. This is also the profound meaning of Nietzsche's doctrine concerning the morality of masters and slaves: behind Nietzsche's apparent atheism was hidden a desperate thrust towards the freedom of the innocent man who gave names to all things and ruled over all things. With still greater right Nietzsche could have spoken of the truths of masters and the truths of slaves, but he lacked the daring to do this.
We are so strictly bound by the fundamental principles of the ancient philosophy which we have imbibed with our mother's milk that every attempt to oppose to these principles the truth of the Bible appears to us not only mad but sacrilegious. The most remarkable representatives of the philosophy of the Middle Ages expected salvation from the fruits of the tree of knowledge and, despite his flights of genius, St. Augustine himself did not leave the eyes of the Greeks. He who so glorified the Bible nevertheless aspired to self-evidences; he who rose with such violence against Pelagius and his friends nevertheless believed that freedom consisted in the liberty to choose between good and evil and made man's salvation dependent on his merits and works. Thus when one compares St. Augustine's own writings with those fragments of the Psalms and other books of the Bible that he so joyfully interpolates in them, one cannot fail to notice, despite all the author's ingenuity, something artificial. It is not a free flight but a struggle against the all too human law of gravity: the arguments with which he abundantly sprinkles his reflections and a certain vehemence of tone remind us always that, even when it is a question of grace, the "mechanism" of understanding is not overcome.
The "habit of reflecting on his faith," as well as the invincible need die moralische Betrachtung der religiösen zu überordnen (to set the moral point of view over the religious) permeate the whole medieval philosophy and particularly the doctrine of grace. When we are told "grace does not abolish nature," it may seem that this is a loving tribute to the Creator. But, on the contrary, we must see here a trick of reason which wishes at all costs to preserve its sovereignty. For reason the potentia ordinata (ordered power) of God is much more comprehensible and much more acceptable than his potentia absoluta (absolute power), which it fears at bottom more than everything in the world. Reason seeks and finds everywhere a well-defined order, an arrangement established once for all. It even goes so far as to oppose potentia absoluta to potentia ordinata as a supernatural to a natural order, thus brushing aside in advance every threat against the integrity of its sovereign rights. The following example is sufficiently eloquent in this connection, even though it concerns an unimportant question. We read in St. Thomas Aquinas: "Some say that the animals which are now wild and kill other animals were in that state (before the sin) tame, not only toward men but toward animals. But this is completely unreasonable. For the nature of animals was not changed through the sin of man so that those, for example lions and falcons, for whom it is now natural to eat the flesh of others then lived on plants." Once more we must recognize that St. Thomas is right: "it is completely unreasonable" to assume that the carnivores fed on grass before the fall.
But we read in Isaiah that God does not ask what must be according to the nature of things. The whole world knows the famous words: "the wolf and the lamb shall feed side by side and the lion will eat straw like the bullock." (Isaiah, LXV, 25.) St. Francis of Assisi even succeeded in changing the nature of the wolf merely by means of the soft words "brother wolf." And he succeeded in doing this only because, like Isaiah, he did not wish to "know" and did not aspire to transform the truth of revelation into self-evident and immutable metaphysical principles. For St. Francis of Assisi and Isaiah, unshakableness and immutability, the things that constitute the very essence of knowledge and that human reason seeks so avidly, offered nothing enticing: on the contrary, these terrified them. "'Two times two makes four' is already the beginning of death": every line of the Bible tells us this again and again. And if one had declared to the Apostle that "in a universe where evil is a given fact, its reality cannot be denied," he would have answered with the well known words: "The fool saith in his heart, 'there is no God.'" For the fact, the given, does not at all have the right to limit the divine omnipotence: the divine "very good" denies the fact as well as all "given," and only human reason sees in the "wherefore" (hoti) the "first and the beginning" (to proton kai archę) which it has never been.
If one had proven to the Apostle with all the required evidence, like "two times two makes four," that man is descended from the ape, neither proofs nor evidence would have convinced him. He would perhaps have repeated Dostoevsky's words, "but what does it matter to me?" Probably, however, he would have recalled the Bible: "...as thou hast believed, so be it done unto thee." In other words, if you believe that you are of God, you are of God; if you believe that you come from an ape, you come from an ape: "the righteous shall live by faith." This is "entirely unreasonable," and it is beyond doubt that reason would direct the entire arsenal of its vituperabilia against the daring man who would have the audacity to affirm that among men some are descended from Adam who was created by God, and others from an ape that came naturally into the world and that no one created - and that this depends only on their faith.
For faith has nothing to do with this: it is knowledge and the eternal truths of the intellectus that rule in this domain. "For the intellectual light is nothing but a certain similarity through participation in the uncreated light." It is not given to any faith to overcome the self-evidence of the truths of reason. They are truths of reason precisely because no power in the world can overcome them. And if we attribute immutability to the Creator Himself it is only because we wish to see and can see in Him the "uncreated light": the method of analogy authorizes and obliges us to do so.
 Summa Th. I, 84, 5, concl.
 Two historians as different as J. Tixeron and Harnack, who both, however, had the greatest admiration for St. Augustine, cannot prevent themselves from emphasizing "his habit of reflecting on his faith" (Tixeron, Histoire des Dogmes, II, P. 362) and to remark that in him, "the moral point of view dominates the religious point of view" (Harnack, III, 216).
 Summa Th. I, 1 and 2.
 Summa Th. I, 96 ad sec.