And he was magic

Posh's great contribution to cybernetics is to take seriously the notion of interaction in the circular processes that lie at the heart of the subject . From his earliest days he worked with interactive systems. His master wor k, conversation theory, epitomises the interactive system, which he then ex tended and generalised into the interaction of actors theory. hi this paper , the requirements that conversation places on our understanding of partici pants is presented in the form of a specification. In particular, the ways of behaving and the assumptions under which we have to behave if we are to be able to converse with success are expounded. These are in great contrast to neo-Darwinian assumptions. The difference between communication by code and communication by conversation is explored, and the primacy of conversa tional communication is argued. Finally, it is claimed that the ways of beh aving and the assumptions that are the requirements for a conversation to t ake place are presented as personal qualities that were particularly appare nt in Pask himself.