ABSTRACT
It is difficult to contribute a chapter labelled as 'predominantly negative' without seeming to be just that. Moreover, the larger the output of any single person, and the larger the related theory, the greater the potential for criticism. It is inevitably easy to criticize the theory, its application, its assumptions, the evidence supporting it, from some standpoint or other. There would be no point unless it were worth the effort and recognized that constructive, or even negative, criticism may be a valid and ultimately productive activity, that if it is, it can only be so as a function of what is criticized. There is plenty of evidence in the biological sciences that parasitic activity can be a productive part of effective cycles!
