"...Philosophy is not a foundation or preparation for theology, nor does it clarify the language that theology uses; rather, it is employed for pedagogical purposes in order to make its subject matter more accessible...to the entire human race, which suffers from a defectum intellectus nostri (a defect of our mind), like the man born blind and like those who walk in tenebrae."
The subject matter of the other sciences is not more certain that that of theology but rather more apparent to us. Thus "Nothing prevents that which is more certain according to nature to be less certain for us, due to the weakness of our mind...Hence the doubt that comes to some with regard to the articles of the faith is not due to any lack of certitude in the articles but is due to the weakness of the human intellect."
"Through revelation, human beings are allowed to participate in a luminosity that would otherwise surpass them--the intense vision of the saints--and this participation amounts not so much to an abstract knowledge as to a 'science' by way of shared experience. How redolent of [Aquinas'] John commentary, of course, is this language of light and participation. Theology draws out in a disciplined and logically focused way the implications of this experience."
Barron, The Priority of Christ, pp. 151, 150.
Cf. The Commentary of Saint Thomas Aquinas to the Prologue of the Gospel of Saint John (Chapter 1:1-14).