Remus thought on his next words carefully before he spoke, visibly turning it over before speaking. "Your father is right, in a sense. Knowledge is power. When you know an enemy's weakness before going into a fight, you don't need to fight as hard or as quick as they will. An advantage. Same going to learn a spell, isn't it? If you understand how it works, it doesn't take as long to perfect it. It still will only get you so far, though. Your enemy might just be that much quicker than you and you won't be able to get to his weakness. Never learning the flick of the wand means you could otherwise know the spell perfectly and never be able to perform it correctly. The two must go hand in hand for the best possible outcome. Does that make sense?"