Discovery as the context of any scientific justification

Summary The analysis of philosophically important themes can depart from two different angles. The first one investigates the various answers that have been given to a certain issue, like that of the problem of knowledge, the justification of theories, the notion of culture, etcetera. These answers are often mutually contradictory which, by the way, facilitates their overview (like the schemes of rationalism-empiricism, justification-discovery, universalism-relativism). A second approach starts from the problems (or: problematique) behind the divergent answers (e.g., foundationalism behind both, empiricism and rationalism).In the following sections the issue of discovery is discussed. Here the second line of approach has been followed, not only by making visible a same problematique, but more by trying to set out the common context of the discussion about context of discovery and context of justification. The idea is that this discussion, or better the shift taking place in that discussion, finds its reason in a context in which the distance between traditional methodology and contemporary scientific practice, also between scientific knowledge and the experience of reality has become greater. This is related to the deepening awareness of the cultural context of scientific method. Man and world, scientific method and cultural context are always interacting.From this point of view quite different philosophical approaches show nevertheless similar features pointing to new solutions. A more psychological approach to scientific method (like: Gordon's and Grmek's, even perhaps Gutting's reinterpretation of Popper) and a sociological one (e.g., Barnes, Bloor, and already Durkheim) are opposed to a more logically structured analysis of Nagel, Hempel, and also Popper. Nevertheless the view on the flexibility of scientific method defended along different lines by for instance Achinstein, Bachelard, Hesse, Piaget, Polanyi, Toulmin manifests a certain convergence in those divergent standpoints, the more so since often the cultural context of science is being stressed (e.g., Ladriére, Prigogine, Needham).The miscellany of philosophical orientations, presented in the following sections, can in this way perhaps give profile to deeper tendencies: to relate again scientific method to the context of culture and of human strategy in general. This does not blend, however, the distinction between context of justification and context of discovery. By changing their roles a new overview of this dilemma becomes possible. There is no juxtaposition of both, nor has the one to be absorbed by the other. The conclusion will be that there are still two contexts, but that one is wider, less defined and demarcated from the wider field of daily culture, and that the other is more restricted, functioning as a kind of safetydevice on behalf of the wider strategy of discovery. In such a way discovery is regarded as the wider context of the more restricted context of justification.     

The logical study of science

The relation between logic and philosophy of science, often taken for granted, is in fact problematic. Although current fashionable criticisms of the usefulness of logic are usually mistaken, there are indeed difficulties which should be taken seriously — having to do, amongst other things, with different scientific mentalities in the two disciplines (section 1). Nevertheless, logic is, or should be, a vital part of the theory of science. To make this clear, the bulk of this paper is devoted to the key notion of a scientific theory in a logical perspective. First, various formal explications of this notion are reviewed (section 2), then their further logical theory is discussed (section 3). In the absence of grand inspiring programs like those of Klein in mathematics or Hilbert in metamathematics, this preparatory ground-work is the best one can do here. The paper ends on a philosophical note, discussing applicability and merits of the formal approach to the study of science (section 4).I would like to thank David Pearce and Veikko Rantala for their helpful comments.     

The level of organization of the motor schema

The interpretations of Piaget and Schmidt on the level on which the motor schema is supposedly effective were evaluated in pre-school children of different ages in a throwing task. In an analysis of variance on the accuracy scores, significant main effects for age, sex, and throwing arm were found. Further, the results showed no relationship between accuracy scores with the preferred and non-preferred arm in the younger group, while in the older group a moderate relationship was found. This result was interpreted in terms of structural development and as a warning for studies where Schmidt's variability-of-practice hypothesis is tested.     

Some kinds of modal completeness

In the modal literature various notions of completeness have been studied for normal modal logics. Four of these are defined here, viz. (plain) completeness, first-order completeness, canonicity and possession of the finite model property — and their connections are studied. Up to one important exception, all possible inclusion relations are either proved or disproved. Hopefully, this helps to establish some order in the jungle of concepts concerning modal logics. In the course of the exposition, the interesting properties of first-order definability and preservation under ultrafilter extensions are introduced and studied as well.     

Perceptual interpretation of complex line patterns

Leeuwenberg's coding system for the representation of line pattern interpretations is tentatively applied to the interpretation of complex line patterns, that is, line patterns with intersecting lines. Perceptually preferred interpretations of complex line patterns can only be predicted correctly if two requirements are met: (a) The codes of line patterns should contain information about the objects represented by the line patterns, not about the line patterns as drawings; and (b) effects of the gestalt law of good continuation have to be taken into account.     

Stiffness as a control variable in motor performance

In the experiments described in this article we investigated the control of stiffness of the effector system in relation to parameters of the movement. If the velocity of a movement is chosen, it appears that at the same time the stiffness of the effector system is set to a preferred value. By changing the instruction given to the subject it is possible to change the relationship between velocity and stiffness without changing the kinematic parameters of the movement.Finally, the changes of stiffness and velocity in a learning process are studied. In conformity with what might be expected on intuitive grounds, it is found that velocity increases spontaneously during learning while stiffness decreases. The results are discussed in connection with the generation of motor programmes.