He loves truly, not passionately.

With his thesis clear in his mind, he draws his sword, salutes the universe, kneels at the cross, and then, with joy in his heart, or rather a deep and steady sense of well-being, moves forward to the world, prepared to fight.

Fighting is the thing.
Yes, but here is neither Don Quixote nor Falstaff.

He will fight warily, take no unnecessary risk, and strike only when he is perfectly sure of striking home.
You must not think of him as old beyond his years (he is only a little over forty) but rather as one who was wise from his youth up.

He has never flung himself with emotion into any movement of the human mind, not because he lacks devotion, but because he thinks the victories of emotion are often defeats in disguise.