A Mathematical Equation Stands Forever.

Small Is The Number Of Them That See With Their Own Eyes And Feel With Their Own Hearts.

If One Asks The Whence Derives The Authority Of Fundamental Ends, Since They Cannot Be Stated And Justified Merely By Reason, One Can Only Answer: They Exist In A Healthy Society As Powerful Traditions, Which Act Upon The Conduct And Aspirations And Judgments Of The Individuals; They Are There, That Is, As Something Living, Without Its Being Necessary To Find Justification For Their Existence.

In The Matter Of Physics, The First Lessons Should Contain Nothing But What Is Experimental And Interesting To See. A Pretty Experiment Is In Itself Often More Valuable Than Twenty Formulae Extracted From Our Minds.

All Our Thoughts And Concepts Are Called Up By Sense-experiences And Have A Meaning Only In Reference To These Sense-experiences. On The Other Hand, However, They Are Products Of The Spontaneous Activity Of Our Minds; They Are Thus In No Wise Logical Consequences Of The Contents Of These Sense-experiences. If, Therefore, We Wish To Grasp The Essence Of A Complex Of Abstract Notions We Must For The One Part Investigate The Mutual Relationships Between The Concepts And The Assertions Made About Them; For The Other, We Must Investigate How They Are Related To The Experiences.

Things You Can Get Access To, You Should Never Memorize.