Manifestum est enim quod homo per intellectum cognoscere potest naturas omnium corporum, said St. Thomas Aquinas: “For it is manifest that man is able to know physical things through the intellect.”
The truth that the human mind is able to know the natures of all bodily things may indeed be manifest, as St. Thomas Aquinas here testifies, but it is no less noble for being evident. By this statement, Aquinas did not mean that any one of us in fact knows all things, nor did he mean that the natures of material things are all equally open to our knowing them, nor indeed that our knowledge exhausts their intelligibility or even attains the specific differences of natural bodies. Yet he certainly did mean to point to the universality of the mind as a power of knowing. The mind is not an organ like the eye that has but one proper object—color—and can say nothing about the proper objects of the other senses. The savor, aroma, and temperature of a glass of Burgundy are things that the eye cannot see.