According to a classical, antigen-driven view of the immune system, autoimmunity is due to the presence of self-reactive lymphocyte clones which have not been eliminated. However, computer simulations of the immune network show that the greater the degree of connectivity of a clone, the greater its degree of tolerance to chronic antigenic stimulation. This tolerance does not correspond to an absence of response on the part of the system as a whole. On the contrary, stimulation by a ‘tolerogenic antigen’ results in widespread modification and overall activation of the whole network. This suggests that on an autopoietic network view of the immune system, autoimmunity arises not because of the presence of self-reactive clones, which is completely normal, but because such clones are inadequately connected to the network. This amounts to a complete reversal in perspective, whose significance for the clinical treatment of autoimmunity and the future of immunology is discussed.

This article is a critical examination of the possible relevance of a specific approach to cognitive science for systemic family therapy. I provide a way of comparing the conceptual backgrounds for both these fields and, on that basis, propose some conclusions that underline the difficulty of the task.

After some ten years of faltering development, the network approach in immunology is finally heading toward steady ground. At a recent international workshop, experimentalists and theoreticians discussed some of the latest developments, including an impressive array of novel results and applications to fundamental properties of biological immune networks: connectivity, patterns of dynamic activity, ontogenesis, and tolerance.

This paper is a modest attempt to chart something of the broad trends in contemporary philosophy (the philosophy of the last half century)–trends against which personal construct theory might be aligned, evaluated, or simply reflected upon. These trends themselves emerge from a complex scene in philosophical effort. This scene is marked by increasing specialization, the appearance of new, sometimes interdisciplinary approaches (e.g., bioethics), and the emergence of new sociohistorical and technical phenomena that give rise to new problems. The material that follows is in three parts. The first presents some general observations concerning philosophy and the broadest outline of its development. The second considers the nature of personal construct theory in terms of its own constructivist philosophy, and in relation to other historical philosophical systems, particularly phenomenology. The third part relates personal construct theory to the outline in the first part and attempts some conclusions. In general, I will suggest that as concern with process or praxis moves further toward center stage in philosophy, personal construct theory comes more and more into prominence and its philosophical integrity becomes more obvious.

This chapter discusses a formal model of human and machine learning called participatory learning. This model allows the representation of machine learning in a constructivist framework. In this model, the learner’s previous beliefs play an important role in the assimilation of further information. A central aspect of the theory is the degree of compatibility between observations and belief. In a constructivist theory, learning is a bootstrap process. The name participatory learning highlights the fact that the learner’s current knowledge of the subject participates intimately in the learning process. Central to participatory learning is the idea that an exogenous observation has the greatest impact on learning when the observation is largely compatible with the present belief system. In particular, observations in conflict with current core constructs or strongly held beliefs are discounted. The role of arousal or anxiety can be thought of as salient and/or massed negative feedback.