“ Therefore the universal principle of the practical intellect does not move save through the medium of the particular apprehension of the sensitive part, as is said De Anima iii, 11. ”
 Thomas Aquinas, Summa Theologica (1274). copy citation

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“2: The choice of a particular thing to be done is as the conclusion of a syllogism formed by the practical intellect, as is said Ethic. vii, 3. But a singular proposition cannot be directly concluded from a universal proposition, except through the medium of a singular proposition. Therefore the universal principle of the practical intellect does not move save through the medium of the particular apprehension of the sensitive part, as is said De Anima iii, 11. Reply Obj. 3: Intelligibility is incompatible with the singular not as such, but as material, for nothing can be understood otherwise than immaterially. Therefore if there be an immaterial singular such as the intellect, there is no reason why it should not be intelligible.
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