The highlighted passage reads “When you teach any branch of physics you must motivate the formalism - it isn't any good just to present the formalism and say that it agrees with experiment - you have to explain to the students why this the way the world is. After all, this is our aim in physics, not just to describe nature, but to explain nature.”
https://files.mastodon.social/media_attachments/files/110/305/383/041/176/063/original/c9eec4ac0f445063.jpeg