Abstract
Albert Einstein, one of the greatest scientists of all time, described the "gulf" thatlogically separates the concrete world of hard objects on the one hand from theabstract worldf of ideas on the other. He wrote: Wehave the habit of combining certain concepts and conceptual relations(propositions) so definitely with certain sense experiences that we do notbecome conscious of the gulf - logically unbridgeable - which separatesthe world of sensory experiences from the world of concepts and propositions(1944, p. 289).