
— Karl Raimund Popper, buch Conjectures and Refutations
Von den Quellen unseres Wissens und unserer Unwissenheit. Vorlesung vor der Britischen Akademie am 20. Januar 1960. In: Vermutungen und Widerlegungen, Band 1, S. 45 books.google http://books.google.de/books?id=pPvIR2oEgM4C&pg=PA45
"It might be well for all of us to remember that, while differing widely in the various little bits we know, in our infinite ignorance we are all equal." - On the Sources of Knowledge and of Ignorance. Annual Philosophical Lecture before the Britsh Academy 20 January 1960. In: Conjectures and Refutations - The Growth of Scientific Knowledge. p. 38 books.google http://books.google.de/books?id=fZnrUfJWQ-YC&pg=PA38
Conjectures and Refutations (Vermutungen und Widerlegungen. 1963, engl.)