Classical conservation theories (from Ruskin to Brandi) are characterized by their close adherence to truth. These theories are currently dominant, but criticism and new alternatives are developing and gaining momentum. Three crucial notions in classical theories have been criticised: reversibility, universality and objectivity (including objective determination of damage and the notion of scientific conservation). As a result of these criticisms, emerging contemporary theory of conservation has substituted the notions of function, use or value of the conservation object for that of truth. A representative list of sources is discussed.