but if times and affairs change, he is ruined if he does not change his course of action. But a man is not often found sufficiently circumspect to know how to accommodate himself to the change, both because he cannot deviate from what nature inclines him to do, and also because, having always prospered by acting in one way, he cannot be persuaded that it is well to leave it
 Niccolò Machiavelli, The Prince (1532). copy citation

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Author Niccolò Machiavelli
Source The Prince
Topic action change
Date 1532
Language English
Reference
Note Translated by W. K. Marriott
Weblink http://www.gutenberg.org/files/1232/1232-h/1232-h.htm

Context

“Changes in estate also issue from this, for if, to one who governs himself with caution and patience, times and affairs converge in such a way that his administration is successful, his fortune is made; but if times and affairs change, he is ruined if he does not change his course of action. But a man is not often found sufficiently circumspect to know how to accommodate himself to the change, both because he cannot deviate from what nature inclines him to do, and also because, having always prospered by acting in one way, he cannot be persuaded that it is well to leave it; and, therefore, the cautious man, when it is time to turn adventurous, does not know how to do it, hence he is ruined; but had he changed his conduct with the times fortune would not have changed. Pope Julius the Second went to work impetuously in all his affairs, and found the times and circumstances conform so well to that line of action that he always met with success.” source