Gee. Professor, if concepts have no need to be manifested as objects, that kinda puts you out of a job, doesn't it? We'll all just think about a concept, such as "Liberty", "Flight", "Love", or "Motion", and melt down those extraneous chunks produced by Rodin, Brancussi, Calder and Bartholdi.
Precisely! What is Art, if not the physical/tangible expression of an idea?