Current state of the ‘systemic or structural view’ of parts of the world is considered and concluded that it is largely speculative, fragmented, with no accepted principles regarded as fundamental which could be exposed at least to thought experiments by means of appropriate models. The practice of information systems (IS) is part of this fragmentation which is aided by its current description. The notion of representation or modelling of parts of the world is described as related, ‘subject – predicate forms’ which when transmitted become communication. Information is defined as ‘message encoded in a medium’ and operationally in the context of linguistic modelling as the ‘subordinate clause of sentences with information bearing verbs’. This definition enables the flow of information and IS to be modelled following the methods of systems science as outlined. The quantity of selective and semantic information is worked out leading to precision and to ranges of information to be presented to a living operator for selection and action, or not.