"Now we have said that truth resides primarily in the intellect; and secondarily in things, according as they are related to the divine intellect. If therefore we speak of truth, as it exists in the intellect, according to its proper nature, then are there many truths in many created intellects; and even in one and the same intellect, according to the number of things known. Whence a gloss on Psalm 11:2, "Truths are decayed from among the children of men," says: "As from one man's face many likenesses are reflected in a mirror, so many truths are reflected from the one divine truth." But if we speak of truth as it is in things, then all things are true by one primary truth; to which each one is assimilated according to its own entity. And thus, although the essences or forms of things are many, yet the truth of the divine intellect is one, in conformity to which all things are said to be true."
~St. Thomas Aquinas: S.T., I, Q. 16. art. 6.
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