Zeno of Citium

A bad feeling is a commotion of the mind repugnant to reason, and against nature.

Zeno of Citium

as quoted in Tusculanae Quaestiones by Cicero, iv. 6

If melodiously piping flutes sprang from the olive, would you doubt that a knowledge of flute-playing resided in the olive? And what if plane trees bore harps which gave forth rhythmical sounds? Clearly you would think in the same way that the art of music was possessed by plane trees. Why, then, seeing that the universe gives birth to beings that are animate and wise, should it not be considered animate and wise itself?

Zeno of Citium

as quoted in De Natura Deorum by Cicero, ii. 8

(The end is) life in agreement with nature.

Zeno of Citium

as quoted by Diogenes Laërtius, in Lives of Eminent Philosophers, "Zeno", 7.87: “This is why Zeno was the first (in his treatise On the Nature of Man) to designate as the end ‘life in agreement with nature’ (or living agreeably to nature)...”

No evil is honorable; but death is honorable; therefore death is not evil.

Zeno of Citium

as quoted in Epistles No. 82, by Seneca the Younger

The reason why we have two ears and only one mouth is that we may listen the more and talk the less.

Zeno of Citium

as quoted in Diogenes Laërtius, Lives and Opinions of Eminent Philosophers, vii. 23

Happiness is a good flow of life.

Zeno of Citium

as quoted by Stobaeus, ii. 77

That which exercises reason is more excellent than that which does not exercise reason; there is nothing more excellent than the universe, therefore the universe exercises reason.

Zeno of Citium

as quoted in De Natura Deorum by Cicero, ii. 8; iii. 9