Why are there extremists?

Our intolerance of uncertainty can leave us clutching at any form of certainty. Research shows that the certainty offered by fundamentalist religions, extreme political groups, radical interest groups, and conspiracy theories promises a tempting relief to our anxiety.
 
Part of us knows what is being promised is not the whole truth because it is so polished and over-simplified, but it is preferable to claim to know rather than admit that, for a great deal of life, we cannot know.

Beyond Your Confines
Chris Warren-Dickins