Perhaps some Platonist will come up with the following conjecture. If God created minds for the sake of the first light, and if they are made ready to acquire that light both by knowledge of the divine goodness but most of all by love of it – given that knowledge forms them thence with splendor (lumen) and love re-forms them hence and thither with light (lux) – it is probable that justice divine wishes absolutely none of the minds to be lacking in any faculty and occasion for knowing and loving God forever. But because both knowing and loving have been withheld by the malign necessity of fate from many who die before the use of reason and again from those who are stupid from the onset, it is appropriate that divine providence compensate them for such a faculty, either in this life on some occasion and in some marvelous way, or at least in another life, lest someone be deprived of the principal end of [our] species without any fault of his own. Accordingly, with the souls of these [infants and idiots], though it never happens here [on earth], yet when they are released from bodies and dwell in that splendor we have described and recognize the Creator in His creatures, they are set ablaze step by step with such an ardent love of the Creator that they are made ready to receive the light itself at an appointed time. At an appointed time, I say, because only the angelic minds, all of them being in eternity, either advance or fail to do so in a moment, but souls which already in a natural way turn aside toward temporal things enact their own work in time – for a longer time in the body, but for a much shorter time outside the body. They do so in a moment only when they have been wellnigh transformed into the angelic nature. But if souls confined to the punishments of purgatory, though they are in a much worse condition and location, nonetheless arise again even to blessedness, then it should not appear surprising that souls placed in the middle region of painlessness, closer as it is to blessedness, can advance all the way to blessedness. Philosophers have formed these opinions in the main about infants.
Marsilio Ficino, The Platonic Theology: Volume 6. trans. Michael J.B. Allen (Cambridge: Harvard University Press, 2006), 211-13.