“When science goes beyond the objective observation of facts and attempts to appraise and explain them, the field opens wide for speculation; each one then advances a theory of his own, trying to make it prevail and defending it relentlessly. Do we not see every day the most contradictory opinions, one after another, be proposed and rejected, sometimes repealed as absurd errors, only to be later proclaimed as indisputable truths? Facts are the sole criterion of reality, the argument that admits of no reply. In the absence of facts, doubt is the choice of the wise man.”
~ The Spirits’ Book, by Allan Kardec