91. Never set to work at anything if you have any doubts about its prudence. #TAOWW

91. Never set to work at anything if you have any doubts about its prudence. A suspicion of failure in the mind of the doer is proof positive in that of the onlooker, especially if he is a rival. If in the heat of action your judgment wavers, it will afterwards in cool reflection be condemned as folly. Action is dangerous where prudence is in doubt—better leave such things alone. Wisdom does not trust probabilities, it always marches in the midday light of reason. How can an enterprise succeed which the judgment condemns as soon as it was conceived? If resolutions passed unanimously by an inner court often turn out badly, what can we expect of those undertaken by a doubting reason and a vacillating judgment. 

THE ART OF WORLDLY WISDOM BY BALTHASAR GRACIAN
TRANSLATED BY JOSEPH JACOBS 1892