At the time Vygotsky wrote, there were, according to Luria, two dominant approaches to understanding the psychological difference between modern and ancient people. One point of view, associated with the French scholar Levy-Bruhl, argued that there is a fundamental psychological gap between modern and premodern peoples. The alternative view was to deny the existence of such a gap. This position was articulated by the anthropologist Franz Boas, who claimed that the ancient mind does not differ in any qualitative way from the modern mind.
Boas and his followers played an important role in discrediting claims of racial superiority, they argued, correctly, that the biological hardware of the human brain does not differ significantly between human groups, or between modern and ancient people. What they ignored, however, is that the cognitive software that we run on those brains could be different across historical epochs.
Working within a Marxist framework, Vygotsky and Luria proposed a third model. While they accepted the evolution of human mentality, they located the source of change not in biology, but in socio-economic and historical forces. They asserted that our own thoughts, which we believe to be private and intimate, are in fact, deeply shaped by social forces. In this view, the link between the individual and the larger society is language. So while animals can think, human thinking resembles an inner monologue.
Developmental psychologists had noted that children often spoke out loud to themselves, with little or no concern about an audience. Traditionally this behavior has been labeled egocentric speech as distinct from communicative speech, and it is thought to be related to the young child’s difficulty in taking the perspective of others. But Vygotsky (1996) amended this view with the hypothesis “that egocentric speech is actually an intermediate stage leading to inner speech” (p. 32).
This is a startling proposal. Vygotsky is saying that in the course of development we internalize the external linguistic environment and, in this sense, even our thoughts are social in origin.
Vygotsky and Luria were explicit in their rejection of the central claim of the Cartesian world view. While Descartes asserted, “I think therefore I am” as the foundational axiom for all philosophy, Luria countered with, “the perception of others and the processes of self-perception are shaped through social activities” (p. 19). In other words, self-consciousness itself is the product of socialization and impossible without language.
One can pause here and ask: how plausible is this Vygotskian claim? Can we believe that consciousness is the exclusive property of humans or that animals cannot think because they lack a human language? Here we see the influence of a bias towards human thought which, in the light of emerging knowledge of animal cognition, is no longer tenable. Curiously, Descartes also had a similar bias against animal consciousness and cognition.
While it is clearly false to disparage the abilities and sentience of non-linguistic animals, it is clear, that for the human animal, language is a bridge to larger social forces and plays a strong role in shaping our mental architecture. In turn, our individual psychology binds us to and shapes the larger social world.