But if men would give heed to the nature of substance they would doubt less concerning the Proposition that Existence appertains to the nature of substance: rather they would reckon it an axiom above all others, and hold it among common opinions. For then by substance they would understand that which is in itself, and through itself is conceived, or rather that whose knowledge does not depend on the knowledge of any other thing.
Baruch SpinozaSurely human affairs would be far happier if the power in men to be silent were the same as that to speak. But experience more than sufficiently teaches that men govern nothing with more difficulty than their tongues.
Baruch Spinoza