The ultimate destiny of the human race is the greatest moral perfection, provided that it is achieved through human freedom, whereby alone man is capable of the greatest happiness.
This can never become popular, and, indeed, has no occasion to be so; for fine-spun arguments in favour of useful truths make just as little impression on the public mind as the equally subtle objections brought against these truths. On the other hand, since both inevitably force themselves on every man who rises to the height of speculation, it becomes the manifest duty of the schools to enter upon a thorough investigation of the rights of speculative reason, and thus to prevent the scandal which metaphysical controversies are sure, sooner or later, to cause even to the masses.
Enthusiasm is always connected with the senses, whatever be the object that excites it. The true strength of virtue is serenity of mind, combined with a deliberate and steadfast determination to execute her laws. That is the healthful condition of the moral life; on the other hand, enthusiasm, even when excited by representations of goodness, is a brilliant but feverish glow which leaves only exhaustion and languor behind.
No state at war with another state should engage in hostilities of such a kind as to render mutual confidence impossible when peace will have been made.
If, like Hume, I had all manner of adornment in my power, I would still have reservations about using them. It is true that some readers will be scared off by dryness. But isn't it necessary to scare off some if in their case the matter would end up in bad hands?
Enlightenment is the liberation of man from his self-caused state of minority... Supere aude! Dare to use your own understanding!is thus the motto of the Enlightenment.
All the interests of my reason, speculative as well as practical, combine in the three following questions: 1. What can I know? 2. What ought I to do? 3. What may I hope?