Man cannot survive except ...

Man cannot survive except through his mind. He comes on earth unarmed. His brain is his only weapon. Animals obtain food by force. man had no claws, no fangs, no horns, no great strength of muscle. He must plant his food or hunt it. To plant, he needs a process of thought. To hunt, he needs weapons,and to make weapons - a process of thought. From this simplest necessity to the highest religious abstraction, from the wheel to the skyscraper, everything we are and we have comes from a single attribute of man -the function of his reasoning mind.
Man cannot survive except through his mind. He comes on earth unarmed. His brain is his only weapon. Animals obtain food by force. man had no claws, no fangs, no horns, no great strength of muscle. He must plant his food or hunt it. To plant, he needs a process of thought. To hunt, he needs weapons,and to make weapons - a process of thought. From this simplest necessity to the highest religious abstraction, from the wheel to the skyscraper, everything we are and we have comes from a single attribute of man -the function of his reasoning mind.

Quotes from the same author

A creative man is motivated by the desire to achieve, not by the desire to beat others.
The truth is not for all men, but only for those who seek it.
The action required to sustain human life is primarily intellectual; everything man needs has to be discovered by his mind and produced by his effort.
If you want to know the one reason that's taking me back, I'll tell you: I cannot bring myself to abandon to destruction all the greatness of the world, all that which was mine and yours, which was made by us and is still ours by right - because I cannot believe that men refuse to see, that they can remain blind and deaf to us forever, when the truth is ours and their lives depend on accepting it.
Run for your life from any man who tells you that money is evil. That sentence is the leper's bell of an approaching looter. So long as men live together on earth and need means to deal with one another--their only substitute, if they abandon money, is the muzzle of a gun.