What has not been examined impartially has not been well examined. Skepticism is therefore the first step towards truth.
Denis DiderotYou can be sure that a painter reveals himself in his work as much as and more than a writer does in his.
Denis DiderotThe philosopher forms his principles on an infinity of particular observations. He does not confuse truth with plausibility, he takes for truth what is true, for false what is false, for doubtful what is doubtful, and probable what is probable. The philosophical spirit is thus a spirit of observation and accuracy.
Denis Diderot