A whole from necessary substances is impossible. The whole, therefore, of substances is a whole of contingent things, and the world consists essentia… - Immanuel Kant

"Enlightenment is man's emergence from his self-imposed nonage. Nonage is the inability to use one's own understanding without another's guidance. This nonage is self-imposed if its cause lies not in lack of understanding but in indecision and lack of courage to use one's own mind without another's guidance. Dare to know! (Sapere aude.) "Have the courage to use your own understanding," is therefore the motto of the enlightenment."

But, above all, it will confer an inestimable benefit on morality and religion, by showing that all the objections urged against them may be silenced for ever by the Socratic method, that is to say, by proving the ignorance of the objector.

Young man! Deny yourself satisfaction (of amusement, of debauchery, of love, etc.), not with the Stoical intention of complete abstinence, but with the refined Epicurean intention of having in view an ever-growing pleasure. This stinginess with the cash of your vital urge makes you definitely richer through the postponement of pleasure, even if you should, for the most part, renounce the indulgence of it until the end of your life. The awareness of having pleasure under your control is, like everything idealistic, more fruitful and more abundant than everything that satisfies the sense through indulgence because it is thereby simultaneously consumed and consequently lost from the aggregate of totality.