As regards authority I so proceed. Boetius says in the second prologue to his Arithmetic, 'If an inquirer lacks the four parts of mathematics, he has very little ability to discover truth.' And again, 'Without this theory no one can have a correct insight into truth.' And he says also, 'I warn the man who spurns these paths of knowledge that he cannot philosophize correctly.' And Again, 'It is clear that whosoever passes these by, has lost the knowledge of all learning.'

Argument is conclusive, but it does not remove doubt.

For if any man who never saw fire proved by satisfactory arguments that fire burns. His hearer's mind would never be satisfied, nor would he avoid the fire until he put his hand in it that he might learn by experiment what argument taught.

Reasoning draws a conclusion, but does not make the conclusion certain, unless the mind discovers it by the path of experience.

A little learning is a dangerous thing but none at all is fatal.

A man is crazy who writes a secret in any other way than one which will conceal it from the vulgar.

It is easier for a man to burn down his own house than to get rid of his prejudices.