The Taittiriya Upanishad
The word 'man' as in 'mankind' can be traced back to an ancient Sanskrit word root, man, which means 'to think'. Our species is forever thinking, scheming, dreaming, intending. Such a large part of our mental activity has to do with the future that we have to be reminded to live in the present by wise people.
Another department of our minds is concerned with inquiry, rather than a manipulation of circumstances with a view to getting what we want. Many are the questions asked by inquiring minds, such as the old Aristotelian question, 'What is the good life?' and the Platonic question, 'What is Absolute Good?' Such inquiries seem innocent but may arouse opposition. Socrates ended his days by drinking the hemlock because he asked too many penetrating questions and taught the young to do the same.