A passage from Chrysippus
Chrysippus, (in Cicero, On Fate) 20
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Nothing happens without a cause; whatever happens follows upon something preceding.
Related passages
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Your present opinion founded on understanding, your present conduct directed to social good, your present disposition contented with everything that happens — that is enough.
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Of human life the time is a point, the substance flowing, the perception dull... The only thing that escorts a man on his way is philosophy.
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He who acts unjustly acts impiously. For since the universal nature has made rational animals for the sake of one another, he who acts contrary to nature commits impiety against the highest divinity.