Finally there are simple ideas of which no definition can be given; there are also axioms or postulates, or in a word primary principles, which cannot be proved and have no need of proof.
-- Gottfried Leibniz
   
Gottfried Leibniz   Name:
Gottfried Leibniz
Type:
Philosopher
Nationality:
German
https://www.nutquote.com/quote/Gottfried_Leibniz