…Avicenna argued for the eternity of the world from the claim that the possibility of the world could not be grounded on the pre-existence of the ideas of things in the divine mind. The Averroists, following a very probable reading of Aristotle, argued that God could not know anything other than himself – and certainly could not know individual things. Both arguments appeal to the idea that because God is the most excellent object of thought, he would only think of himself, and so would not have the diversity of rationes of created things in his mind. St. Thomas, on the other hand, not only argued for a multiplicity of ideas of created intelligible natures in the divine mind, he claimed that these divine ideas reached even to the very concretion of the particular things.
God is the cause of a thing not only with respect to its form, but even of its matter, which is the principle of individuation and so the idea in the divine mind is the similitude of both matter and form, and so things are known through it not only universally, but even in the particular.
Thus the ideas or intelligible natures of things, which are similitudes of things in the mind of God, are most perfectly the similitudes of things not only because the the knowledge of God is unable to err or be ignorant, but also because the divine mode of knowing, in a way that infinitely transcends the human intellectual power, can attain to a positive, intellectual apprehension of the concrete particular. The idea of a self within the divine mind is not an abstraction, a generalization, or an inadequate, subordinate representation of the concrete reality. It would not be going to far to say that, in a way that is comparable to how God can be said to be more present to the creature than the creature is to itself, so too the self – the I that is me in the concrete existential situation of my life – more exists in the divine mind than it does in itself.
 Super libri Sententiarum, lib. 2 d. 3 q. 3 a. 3 co sed Deus est causa rei, non solum quantum ad formam, sed etiam quantum ad materiam, quae est principium individuationis; unde idea in mente divina est similitudo rei quantum ad utrumque, scilicet materiam et formam; et ideo per eam cognoscuntur res non tantum in universali, sed etiam in particulari.