Those who are really convinced that they have made progress in science would not demand freedom for the new views to continue side by side with the old, but the substitution of the new views for the old.

We admire the achievements of the Cuban revolution in the sphere of social welfare. We note the transformation from a country of imposed backwardness to universal literacy. We acknowledge your advances in the fields of health, education, and science.

Change based on principle is progress. Constant change without principle becomes chaos.

Favor comes because for a brief moment in the great space of human change and progress some general human purpose finds in him a satisfactory embodiment.

I like progress but I hate change.

I believe that if you have revolutionary potential, you must make the world a better place.