" I only believe those things which can be proved; but I know full well that proofs are relative and can, and are in fact, continually superseded and cancelled out by other proved facts; and therefore I believe that doubt should be the mental approach of all who aspire to get ever closer to the truth, or at least to that much of truth that it is possible to establish. . . "

― Errico Malatesta , Malatesta: Life & Ideas