It is not enough to mean well, it is not enough to believe one is doing right, it is not enough to be earnest, sincere, innocent of evil motives. It is just as essential to possess a balanced mentality, sound reasoning capacity, and unbiased attitude. The Spanish Inquisitors were sometimes saints, Hitler was an ascetic. Many who have brought misery upon mankind were men of excellent private character: the defects of these people were mental rather than moral, and led them to bad thinking and worse judgement. The moral of this is plain: intelligence must be cultivated as fully if not more so than emotions.
-- Notebooks Category 7: The Intellect > Chapter 2: The Service of Intellect > # 67