"You seem all here so hideously rich," says his hero. Thus, there are two meanings mixed together: mockery of an absent-minded savant and admiration of someone who is able to devote his or her entire efforts to a noble cause (hence "ivory", a noble but impractical building material). The term has a rather negative flavor today, the implication being that specialists who are so deeply drawn into their fields of study often can't find a lingua franca with laymen outside their "ivory towers".