When I could have used a wife, I could not support one; and when I could support one, I no longer needed any

I learned to honor human beings, and I would find myself far more useless than the common laborer if I did not believe that this consideration could impart to all others a value establishing the rights of humanity.

It is presumed that there exists a great unity in nature, in respect of the adequacy of a single cause to account for many different kinds of consequences.

Both love of mankind, and respect for their rights are duties; the former however is only a conditional, the latter an unconditional, purely imperative duty, which he must be perfectly certain not to have transgressed who would give himself up to the secret emotions arising from benevolence.

Thoughts without content are empty, intuitions without concepts are blind.

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.

Nothing is divine but what is agreeable to reason.