Perhaps the spirit of adventure, be it mental or material adventure, is a factor so essential in human progress that no emphasis of it is undue.

The pursuit of natural knowledge, the investigation of the world - mental and material - in which we live, is not a dull and spiritless affair: rather is it a voyage of adventure of the human mind, a holiday for reckless and imaginative souls.

Human progress has always been driven by a sense of adventure and unconventional thinking.

There has to be a global mission of human progress.

The liberty of the individual is a necessary postulate of human progress.

The power to question is the basis of all human progress.