For your first question, consensus introduces a truth discerning process onto the indiscriminate votes of the population (democracy).  Indiscriminate votes are better than blind trust in a single source, but the scientific process totally precludes indiscriminate votes from the pursuit of truth.  There's a logically consistent process to arrive at a logical truth; you perform it.

Whether the pursuit is, in truth, important... is the big question.  Many believe that faith is enough, even to behave on provably unprovable things.