The doctrine that the existence of a personal Deity,
   an unseen world, etc., can be neither proved nor disproved, because of
   the necessary limits of the human mind (as sometimes charged upon
   Hamilton and Mansel), or because of the insufficiency of the evidence
   furnished by physical and physical data, to warrant a positive
   conclusion (as taught by the school of Herbert Spencer); -- opposed
   alike dogmatic skepticism and to dogmatic theism.