Stern assigns primordial agency to the person, the basic, agentive particular of the human world. Vygotsky held that all higher mental functions are appropriated from the socio-cultural environment by a process of psychological symbiosis between infant and caretakers. Vygotsky's criticisms of Stern concern: (a) the priority of personhood and appropriation, in that he thought Stern assumed personhood as a Kantian a priori; (b) the relation of meanings to context. Both Stern and Vygotsky figure as ancestors of social constructionism. Dilthey's social constructioninst philosophy favoured a more Vygotskian perspective, since he held that language is a pre-existing bridge by which individuals are able to perform joint actions. Social constructionism holds that active individuals once brought into being by psychological symbiosis are free agents, that there are material conditions for the possibility of social and psychological process, including ethological; that is the existence of natural expressions and that precise emic vocabularies should be preferred to vague, `scientistic' etic ones.