Tomasello disagrees with my position that language is the only human artefact that potentiates internalization. Tomasello's position seems to imply that language can be only verbal. My position is that every object or behavioural act is a symbol if it has all of the following characteristics: symbol must be an object or phenomenon that can be directly perceived through sense organs; meaning of symbols must be shared by organisms; symbols must refer to objects, events or phenomena; it must be possible to use a symbol differently from its referents. Internalization is possible only by means of symbols with such characteristics.
