Few are those who see with their own eyes and feel with their own hearts.

Small is the number of them that see with their own eyes, and feel with their own hearts

Small is the number of people who see with their eyes and think with their minds.

The truth of a theory is in your mind, not in your eyes.

We do not see nature with our eyes, but with our understandings and our hearts.

Few people are capable of expressing with equanimity opinions which differ from the prejudices of their social environment. Most people are even incapable of forming such opinions.