The Truest Philosophy and the Humility of God

At the end of the first book he wrote after his conversion (Contra Academicos) Saint Augustine says that man without the incarnation would be lost in the darkness of various philosophical errors.

Philosophy is saved by the Incarnation

Today, therefore, we see practically no philosophers unless they be either Cynics or Peripatetics or Platonists. The only reason we have the Cynics is that such people find their pleasure in a certain liberty and even licence in life. But as to that which concerns erudition, doctrine, and morals, all of which help the soul, acute and clever men have not been lacking who have taught in their disputations that Aristotle and Plato in such wise agree with one another, which those who are unskilled or examine the matter cursorily think that they disagree; and after many generations and many conflicts there is strained out at last, I should say, one discipline of the most true philosophy. 

Theirs was not a philosophy of this world, which our sacred philosophy rightly detests, but of another, intelligible, world, to the subtlety of reason of which it would never have been able to call back the souls blinded by the multifarious errors of darkness and lost to the heights by the filth of the body, had not the supreme God, descending with a certain clemency for the masses, bent and submitted the authority of his divine intellect even to the human body itself, so that souls, stimulated not only by his precepts but also by his works, might return to themselves and once again see their fatherland.

(My translation based, in part on this one: Contra Academicos 19:42)

Itaque nunc philosophos non fere videmus, nisi aut Cynicos aut Peripateticos aut Platonicos: et Cynicos quidem, quia eos vitae quaedam delectat libertas atque licentia. Quod autem ad eruditionem doctrinamque attinet, et mores quibus consulitur animae, quia non defuerunt acutissimi et solertissimi viri, qui docerent disputationibus suis Aristotelem ac Platonem ita sibi concinere, ut imperitis minusque attentis dissentire videantur; multis quidem saeculis multisque contentionibus, sed tamen eliquata est, ut opinor, una verissimae philosophiae disciplina. Non enim est ista huius mundi philosophia, quam sacra nostra meritissime detestantur, sed alterius intellegibilis; cui animas multiformibus erroris tenebris caecatas, et altissimis a corpore sordibus oblitas, nunquam ista ratio subtilissima revocaret, nisi summus Deus populari quadam clementia divini intellectus auctoritatem usque ad ipsum corpus humanum declinaret, atque submitteret; cuius non solum praeceptis, sed etiam factis excitatae animae redire in semetipsas, et resipiscere patriam, etiam sine disputationum concertatione potuissent.

Augustinus Contra Academicos 19:42