“Man has gone out to explore other worlds and other civilizations without having explored his own labyrinth of dark passages and secret chambers, and without finding what lies behind doorways that he himself has sealed.”
– Stanislaw Lem, Solaris, 1961

Source: Stanislaw Lem, Solaris, trans. J. Kilmartin and S. Cox (New York – London 1970; repr. 1987), 157.