Joint action and group action made precise

The paper argues that there are two main kinds of joint action, direct joint bringing about (or performing) something (expressed in terms of a DO-operator) and jointly seeing to it that something is the case (expressed in terms of a Stit-operator). The former kind of joint action contains conjunctive, disjunctive and sequential action and its central subkinds. While joint seeing to it that something is the case is argued to be necessarily intentional, direct joint performance can also be nonintentional. Actions performed by social groups are analyzed in terms of the notions of joint action (basically DO and Stit).A precise semantical analysis of the aforementioned kinds of joint action is given in terms of time-trees. With each participant a tree is connected, and the trees are joined defining joint possible worlds in terms of state-expressing nodes from the trees. Sentences containing DO and Stit are semantically evaluated with respect to such joint possible worlds. Intentional joint actions are characterized in terms of the notion of we-intention (joint intention), characterized formally by means of a special operator.     

Morgan on deductive explanation: A rejoinder

This paper is mainly a response to Charles Morgan's criticisms (this journal, pp. 511–25) of the author's model of the (formal aspects of) explanation. It is claimed in the paper that with two modifications and some additional specifications the model withstands Morgan's criticisms.     

On radical conceptual revolutions in social science

The paper considers arguments for and against correction and elimination of the basic conceptual categories as well as theories of social science. It is argued that some correction of at least some basic social notions is called for. A great part of the paper consists in a conceptual investigation of such notion of correction in terms of different notions of corrective explanation.     

ON THE APPLICATION OF MATHEMATICAL LEARNING THEORIES. II

The most important components of the empirical adequacy of a mathematical learning theory are claimed to be: truth, explanatory power, information content, refutability, range, and simplicity. The main result of this paper is that the amount of information common to the theory and the empirical evidence can be used to measure the four first of these. As this common information in turn is measured by a certain kind of statistical likelihood test, a basis is found for comparing theories in empirical research. Provisional rules of acceptance for mathematical learning theories in accordance with this are stated.