**Friday, 19 February 2010 **
A Locus for 'Now' - a Modal Perspective
**Tomasz Placek**, Jagiellonian University, Krakow
12:05 pm, 817R Cathedral of Learning
::: photos
Abstract: The notion of spatially extended present requires a non-trivial
relation of being co-present. As the arguments of Putnam, van Benthem and
Stein show, in special relativity (SR) any transitive relation that
satisfies some other natural requirement for co-presence, is either the
identity or the universal relation. Accordingly, there is no good locus for
spatially extended "now" in SR. I will show that if some extra modal
structure is added to SR, an interesting relation of co-presence can be
defined, leading to "nows" of possibly varying spatiotemporal extension. I
will also point out how this approach can be generalized beyond SR. |