[Scientific explanation as a language and its application to psychiatry]

The concept of scientific explanation plays a crucial role in the methodological discussion within psychiatry. This article shows that since scientific explanation employs a language of its own, its syntactic, semantic, and pragmatic dimensions must therefore be analysed with the help of semiotics. The pragmatic dimension is given particular attention because, hitherto, it has been comparatively neglected in the methodological discussion within psychiatry. Furthermore, the concept of explanation is viewed as a problem sui generis and investigated, to begin with, independently of problems such as causality and teleology. By means of the problem of the ambiguity of inductive-statistical explanations, it is shown that scientific explanations which employ statistical laws without taking into consideration the pragmatic concept of the state of knowledge must necessarily come to incomplete and/or contradictory results. The state of knowledge (K) is defined as the set of propositions which are accepted as true by a person (x) at a given time (t). A more precise analysis shows that, within a given state of knowledge, an accepted proposition is generally seen as more or less probable where it can be assigned a value of credibility (B) which lies between 0 and 1. The force of an explanation, in the pragmatic-informative sense, thus consists in the fact that an explanation can increase the credibility value of an explanandum-event (E) through a presentation of particular circumstances (C) and of general laws (T) such that the following holds: BTUC(E) greater than B(E). Depending on the level of the absolute value of BTUC(E), a gradual differentiation is made with respect to the quality of pragmatic-informative explanations. The various types of explanation can be differentiated according to the type of arguments employed in the explanans of a pragmatic-informative explanation; the most important members of this family of explanations are the causal, functional, teleological, and dispositional elements. Finally, the concept of explanation is differentiated from that of understanding, another key concept in psychiatry. In this respect, it is important that the incorporation of pragmatic dimensions into scientific explanation must not be equated with the use of psychological categories; the latter are of importance solely for the concept of understanding. Furthermore, the notion is rejected that in psychiatry a higher value is to be attributed to explanation than to understanding. Rather, both concepts represent different approaches to psychiatric disorders, whereby each employs a language of its own.