Branching Time as a Conceptual Structure

摘要

This paper deals with the history and the philosophy of some important conceptual structures of time and modality. In particular, the focus is on the historical and philosophical background of the introduction of the notion of branching time as a useful conceptual structure in philosophical logic. It is pointed out that the idea was first suggested by Saul Kripke in a letter to A.N. Prior, dated Sept. 3, 1958. It is also shown in the paper that Prior received the idea positively and that he developed it significantly in his later writings, although he at least in the beginning met the idea with some reservation and hesitation. Prior's development of branching time may be understood as a crucial part of his attempt at the formulation of a conceptual framework integrating basic human notions of time, free choice and ethics. Finally, the paper presents some challenges regarding the significance of branching time in philosophy and in the study of information architecture.