The important thing is not to stop questioning. Curiosity has its own reason for existing.[Wichtig ist, dass man nicht aufhört zu fragen. Neugier hat ihren eigenen Seinsgrund.]
Source:Death of a Genius: His fourth dimension, time, overtakes Einstein, Subsection: Old Man's Advice to Youth: 'Never Lose a Holy Curiosity' by William Miller in Life Magazine (May 2, 1955)