I suppose that the trivium is such a powerful tool because it is rooted in the natural and the supernatural: The Trinity. Three is the essence of the metaphysical. I once heard someone say that if you asked a math genius their favorite number it would be divisible by 3. This is how I know I am not a math genius.
When you stumble upon a cord of three it is a good idea to pay attention.
Grammar, Logic, Rhetoric.
Truth, Goodness, Beauty.
Wisdom, Knowledge, Understanding.