物理を理解するとはどういうこととか。Feynmanが次のように書いている。英語で申し訳ないです。訳は「ファインマン物理学」第III巻（岩波書店）で見てください。
どうも私に言われているようで、身にこたえるのですが。
You will have to solve the equations. Each time you solve the equations, you will learn something about the character of the solutions. To keep these solutions in mind, it will be useful also to study their meaning in terms of field lines and of other concepts.
This is the way you will really "understand" the equations. That is the difference between mathematics and physics. Mathematicians are often led astray when "studying" physics because they lose sight of physics.
They say: "Look, these differential equations --Maxwell equations -- are all there is to electrodynamics; it is admitted by the physicists that there is nothing which is not contained in the equations. The equations are complicated, but after all they are only mathematical equations and if I understand them mathematically inside out, I will understand the physics inside out."
Only it does'nt work that way. Mathmaticians who study physics with that point of view usually make little contributions to physics and, in fact, little to mathmatics.
They fail because the actual physical situaions in the real world are so complicated that it is necessary to have a much broader understanding of the equations.
このあとに有名なDiracの言明が続く。「方程式を解かないで、その解の特徴をつかんだときにようやくその方程式を理解する」と。
今日のこの考えはとても貴重であろう。だれにとっても。