Thoughts without content are empty, intuitions without concepts are blind... The understanding can intuit nothing, the senses can think nothing. Only through their union can knowledge arise.
A philosophical attempt to work out a universal history according to a natural plan directed to achieving the civic union of the human race must be regarded as possible and, indeed, as contributing to this end of Nature.
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!
Most men use their knowledge only under guidance from others because they lack the courage to think independently using their own reasoning abilities. It takes intellectual daring to discover the truth.
There will always be some people who think for themselves, even among the self-appointed guardians of the great mass who, after having thrown off the yoke of immaturity themselves, will spread about them the spirit of a reasonable estimate of their own value and of the need for every man to think for himself.