A Man Who Is Certain He

The fuller passage, from an 1819 lecture titled "On the Forms of Matter," reads: "Nothing is more difficult and requires more care than philosophical deduction, nor is there anything more adverse to its accuracy than fixidity of opinion. The man who is certain he is right is almost sure to be wrong, and he has the additional misfortune of inevitably remaining so." Published in Henry Bence Jones's The Life and Letters of Faraday (1870, Vol. 1, p. 310), it reflects an epistemological humility Faraday practiced throughout his career — he habitually tested his own hypotheses against experiment rather than defending them once formed.