Knowing Thyself, That Is The Greatest Wisdom.

Oh, My Dear Kepler, How I Wish That We Could Have One Hearty Laugh Together. Here, At Padua, Is The Principal Professor Of Philosophy, Whom I Have Repeatedly And Urgently Requested To Look At The Moon And Planets Through My Glass, [telescope] Which He Pertinaciously Refuses To Do. Why Are You Not Here? What Shouts Of Laughter We Should Have At This Glorious Folly! And To Hear The Professor Of Philosophy At Pisa Laboring Before The Grand Duke With Logical Arguments, As If With Magical Incantations, To Charm The New Planets Out Of The Sky.

If There Were As Great A Scarcity Of Soil As Of Jewels Or Precious Metals, There Would Not Be A Prince Who Would Not Spend A Bushel Of Diamonds And Rubies And A Cartload Of Gold Just To Have Enough Earth To Plant A Jasmine In A Little Pot, Or To Sow An Orange Seed And Watch It Sprout, Grow, And Produce Its Handsome Leaves, Its Fragrant Flowers, And Fine Fruit.

I Would Beg The Wise And Learned Fathers [of The Church] To Consider With All Diligence The Difference Which Exists Between Matters Of Mere Opinion And Matters Of Demonstration.

Nothing Occurs Contrary To Nature Except The Impossible, And That Never Occurs.

The Vain Presumption Of Understanding Everything Can Have No Other Basis Than Never Having Understood Anything. For Anyone Who Had Ever Experienced Just Once The Perfect Understanding Of One Single Thing, And Had Truly Tasted How Knowledge Is Accomplished, Would Recognize That Of The Infinity Of Other Truths He Understands Nothing.