What religion a man holds, to what race he belongs, these things are not important; the really important thing is this knowledge: the knowledge of God's plan for men. For God has a plan, and that plan is evolution.

We are least open to precise knowledge concerning the things we are most vehement about.

Without self knowledge, without understanding the working and functions of his machine, man cannot be free, he cannot govern himself and he will always remain a slave.

We must always remember with gratitude and admiration the first sailors who steered their vessels through storms and mists, and increased our knowledge of the lands of ice in the South.

The past is a source of knowledge, and the future is a source of hope. Love of the past implies faith in the future.

To know, is to know that you know nothing. That is the meaning of true knowledge.

The learning and knowledge that we have, is, at the most, but little compared with that of which we are ignorant.