This paper contains some considerations on the relation between philosophy of science and science, in particular biology. There is a contrast between formalistic and pragmatic approaches to the structure of scientific thought, which is illustrated by the different viewpoints on the nature of explanation. In an appendix some aspects of the logical structure of teleological explanation are discussed.

In the first parts of this study on the concept of the biological clock it has been investigated how it is used in the field of biorhythmology. The analysis of the contents of the concept is preceded by a survey of the current research in this field.There are two general hypotheses with respect to the ultimate origin of rhythmic phenomena: the Endogenous Timer Hypothesis and the Exogenous Timer Hypothesis. Within the Endogenous Timer Hypothesis two contrasting viewpoints with respect to the (...) structure of the biological clock can be distinguished, which have been called: the Discrete Entity view, and the Organizational view.It has been shown that in the application of the general clock-idea upon the organism a logical distortion is present. The organism is conceived tobe a clock and tohave a clock simultaneously.In anticipation of the analysis of the explanatory value of the concept of the biological clock in part II, it has been put forward that in a number of cases time-measurement can be considered as a superfluous element in the explanation of the phenomena involved.Finally it has been demonstrated that in the case of the Exogenous Timer Hypothesis the concept of the biological clock is not relevant. The Exogenous Timer Hypothesis has been compared with the Endogenous Timer Hypothesis with respect to the criterion of the principle of parsimony, orOccam's razor. (shrink)