"Whate'er thou canst not clearly say thou know'st not."

 

"In vain they call upon the lofty TruthWith sombre conjurations; for the darkShe ne'er endures; for her abode is light.In Phoebus' world, in knowledge as in song,All things are bright. Bright beams the radiant sun;Clear runs and pure his bright Castalian fountain.Whate'er thou canst not clearly say thou know'st not.Twin-born with thought is word on lips of man;That which is darkly said is darkly thought;For wisdom true is like the diamond,A drop that's petrified of heavenly light;The purer that it is, the more its value,The more the daylight shines and glitters through it.The ancients builded unto Truth a temple,A fair rotunda, light as heaven's vault.And freely poured the sunshine from all sidesInto its open round; the winds of heavenAmid its ranks of pillars gayly gambolled.But now instead we build a Tower of Babel,A heavy, barbarous structure. Darkness peepsFrom out its deep and narrow grated casements.Unto the sky the tower was meant to reach,But hitherto we've only had confusion.As in the realm of thought, in that of songIt is; and poesy is e'er transparent ..."

~ Swedish writer Esaias Tegnér from the epilogue to his1820 speech to the graduating class at Lund University. Per Bylund (via Bing) renders the key passage as "What you cannot say clearly, you do not know; with the thought the word is born on the man's lips; what is obscurely said is what is obscurely thought."