Pedagogy and accumulative diversity are as unique and distinctive attributes of the human species as language. The task faced by every community of building skilled, knowing actors emerges from the way in which the accumulative co-operative organization of human action systematically creates a plenitude of diverse settings and cultures, each with its own equipment complex of historically shaped tools and phenomenal objects. Every community is thus faced with the ongoing task of building both the objects and the tools that populate its environment (e.g., archaeological maps, measuring cups in kitchens, surgical tools and classifications of structures within bodies being operated on) and the skilled actors capable of not only recognizing these objects, but knowing in fine detail how to use them to constitute the activities that sustain the community. Simultaneously the co-operative organization of action provides the resources required to construct such actors. Demonstrations of this are found in the way in which repairs in talk make publicly visible the combinatorial organization of language, and the training of new surgeons, and children learning to cook, through simultaneous co-operative action.

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