From the point of view of developmental and comparative psychology, I will explore intermediate grounds in between a stark Davidsonian lingualism (“no language no thought”) on the one hand, and language-of-thought positions on the other hand. Furthermore, I will argue, what we need for describing cognitive development is a dialectical picture that grants cognitive abilities in non- and pre-linguistic creatures, and that stresses specific cognitive foundations for language acquisition in humans, while at the same time recognizing the way speaking shapes and transforms thinking (see Tomasello & Rakoczy, 2003).
In the first part, I will review empirical findings with animals and children on non-linguistic cognition in the areas of object permanence and object individuation –arguably the roots of objective thought- and instrumental action and practical reasoning. The picture that emerges here is that infants and other animals, notably primates, share basic cognitive abilities of objective thought and practical rationality. In the second part the focus will be on social cognition. I will review empirical findings suggesting that infants and great apes share some social cognitive abilities in the form of a simple understanding of perception and intentional action. Humans early in ontogeny, however, develop unique abilities of shared intentionality which are a crucial foundation for entering into culture, language, and proto-institutional practices. Participation in a linguistic community, in a dialectical fashion, then enables children to acquire more sophisticated forms of folk psychology, and cognition generally.