In science the important thing is to modify and change one's ideas as science advances.

There is a principle which is a bar against all information, which cannot fail to keep a man in everlasting ignorance-that principle is contempt prior to investigation.

The great aim of education is not knowledge but action.

The wise man must remember that while he is a descendant of the past, he is a parent of the future.

The society exists for the benefit of its members; not its members for the benefit of the society.

No one can be perfectly free till all are free; no one can be perfectly moral till all are moral; no one can be perfectly happy till all are happy.

All Socialism involves slavery.

Hero-worship is strongest where there is least regard for human freedom.

This survival of the fittest implies multiplication of the fittest.

Be bold, be bold, and everywhere be bold.

Civilization is a progress from an indefinite, incoherent homogeneity toward a definite, coherent heterogeneity.

I’d heard street food was a big thing here in Mexico but I didn’t think it meant the creatures that lived on the street.

Today’s storms usher in tomorrow’s sunshine.

Always have a plan, but be prepared to change it at any given moment.

Climb the mountain not to plant your flag, but to embrace the challenge, enjoy the air and behold the view. Climb it so you can see the world, not so the world can see you.

I left Gorbachev's office thinking that everything about him was outsized: his achievements, his mistakes, and, now, his vanity and bitterness.

A minister who moves about in society is in a position to read the signs of the times even in a festive gathering, but one who remains shut up in his office learns nothing.

I love to get people to sing and play together.

Greatness comes by beginning something that doesn't end with you.

Learn. Ceaselessly. Learn to code, to write persuasively, to understand new technologies, to bring out the best in your team, to find underused resources and to spot patterns.

You are my lover and I am your mistress and kingdoms and empires and governments have tottered and succumbed before now to that mighty combination.