Abstract

In this Eddington Memorial lecture, Von Wright distinguishes two points of view from which a logician may study time. The one focuses interest on the order of temporal events and the macro-aspect of time, its flow from an indefinitely remote past through the present to an indefinitely remote future. The other focuses attention on the micro-aspect of time, the nature of the time medium, on questions of whether time is discrete or infinitely divisible or the internal structure of limited time intervals. Von Wright takes the second point of view and as a result his study of time is different in some respects than that of other contemporary tense logicians. Assuming a Tractatus type ontology of possible worlds which can be totally described by stating the existence or non-existence of all possible states of affairs, Von Wright constructs several logical systems, one of discrete time ordering, another of discrete time division. He shows the latter, which is the most important for his purposes, to be formally related to certain systems of modal logic. An interpretation of this system yields an interesting definition of continuity of change and time. The definition is interesting because of its relation to another result which he derives, namely that this definition of continuity implies that the world sometimes will have to be described as being in two contradictory states at one time, a conclusion which he relates to Hegel's philosophy. This is an original and thought provoking essay.--R. H. K.