A man should always have these two rules in readiness. First, to do only what the reason of your ruling and legislating faculties suggest for the service of man. Second, to change your opinion whenever anyone at hand sets you right and unsettles you in an opinion, but this change of opinion should come only because you are persuaded that something is just or to the public advantage, not because it appears pleasant or increases your reputation.
Marcus Aurelius... Allow yourself a space of quiet, wherein you can add to your knowledge of the Good and learn to curb your restlessness. Guard also against another kind of error: the folly of those who weary their days in much business, but lack any aim on which their whole effort, nay, their whole thought, is focused.
Marcus AureliusWhen jarred, unavoidably, by circumstance revert at once to yourself and don't lose the rhythm more than you can help. You'll have a better grasp of harmony if you keep going back to it.
Marcus AureliusIf you do the task before you always adhering to strict reason with zeal and energy and yet with humanity, disregarding all lesser ends and keeping the divinity within you pure and upright, as though you were even now faced with its recall - if you hold steadily to this, staying for nothing and shrinking from nothing, only seeking in each passing action a conformity with nature and in each word and utterance a fearless truthfulness, then the good life shall be yours. And from this course no man has the power to hold you back.
Marcus Aurelius