The other significant work by Thao, Investigation into the Origin of Language and Consciousness, was not published until 1973 and is not mentioned by Derrida at any point. However, the effort of a brief examination will be repaid in the details it provides for connection between the two thinkers. Thao's second text is no less troubled than his first, frequently losing itself in pedantic distinction and obscure argument whose fundamental premises are never firmly established. It again falls into three section: a history of the development of human society and its tools, an explanation of the child's acquisition of language with reference to this more general history of human development, and a relating of both of these to phychoanalysis and the development of one individual's perception is identical to human development as a whole and therefore with a Hegelian Marxist narrative of social progress.