Many times throughout history people have concluded that their ideas and theories are correct.  We have discovered all the answers and they can't be questioned.  Therefore don't waste your time looking into alternative ideas as they are obviously wrong.

And many times throughout history these people have been shown to be incorrect.  We look back in astonishment just a couple hundred years and realize how incorrect we really were. A favorite scene of mine comes from Star Trek 4 where they go back in time to get some whales to save the future Earth. Dr McCoy berates the doctors about their primitive techniques.  

In 1884 the famous physicist Max Planck was advised against studying physics.  He was told -

"in this field, almost everything is already discovered, and all that remains is to fill a few holes."[1]

When we have certainty that we already know the answer then we limit our own view.  It closes us down to new ideas and to innovative thinking.  We stop questioning and simply go with the accepted theory.  We lock ourselves into a repetitive pattern where it is difficult to experience creative thinking.

The truly great innovators never stop questioning everything around them.  Approaching life with uncertainty broadens your understanding and opens you up to new ideas in amazing ways.

Schools and Universities often stifle creative thinking by presenting only the prevailing theory.  Little or no time is given to opposing theories as it is considered a waste of time.  In school we spend more time memorizing the 'facts' as given to us and little time exploring where they came from.

• 1. Lightman, Alan P. (2005). The discoveries: great breakthroughs in twentieth-century science, including the original papers. Toronto: Alfred A. Knopf Canada. p. 8.