The Latin is great for that initial phrase:
...vivida vis animi... (Latin line I.72)
vivida = lively, vigorous
vis = energy, mental strength, power, vigor
animi (animus) = "the rational soul", LSJ gives "the general power of perception and thought, reason, intellect, mind"
So, a more wordy, less poetic, less metaphysical rendition may be:
"the vigorous power of his perception and thought"
I just get antsy seeing the word "soul" bandied about.