1 - "essential" meaning "life giving". Air and heat are essential in that situation, and are invisible to the eye. Of course, food and water are also essential, but not invisible to the eye.
2 - "essential" in a religious/spiritual meaning. In this case, faith/belief are essential - and invisible to the eye.
btw - if we can't see the souls of living people, why do people believe we can see the souls of the dead?!?
3 - "essential" in the philosophical sense. Things like Rights may be viewed as "essential", and invisible to the eye as they are abstract concepts/ideals.
The line is from Le Petit Prince...The Little Prince. I take it to mean things like love honor integrity truth. Abstract concepts that used to be valued admired sought but due to the white house entertainer and his like-minded ilk are now mocked ridiculed and have been abandoned. A pity that. Thank you for your reply Walt! :)
This post was edited by RosieG at April 15, 2020 3:13 AM MDT
Walt O'Reagun 