Heather Demarest (University of Colorado, Boulder)
4:15-6:15pm, Tuesday October 3, CUNY room 5307 (365 5th Ave, New York NY).
Title: It matters how you slice it: relativity and causation
Abstract: I argue that if we take the standard formulation of special relativity seriously, causation is frame-dependent. Thus, many ordinary causal claims require a parameter to specify the relevant frame of reference. This is in contrast to the widely-accepted belief that the causal structure of the world is objectively and absolutely determined by the light cone structure. Any event that can affect another (so the thought goes) must do so via light or matter, and the spacetime structure will tell us which of those came first, absolutely. For instance, according to Carl Hoefer (2009, 694, italics in original), if we assume that all signals travel slower than or equal to the speed of light, “we may take the light-cone structure of Minkowski spacetime as equally representing the causal structure of spacetime.” I argue that causation in relativistic spacetime is not so simple. Events can be extended in space and time, and events can be related to one another by distance and duration. Yet, according to special relativity, extension in space and time (i.e., distances and durations) are not invariant—they depend upon relative motion. Therefore, when ordinary events enter into causal relations, they do so relative to frames of reference, which can yield different causes and different effects. If you want to keep your promises, or bring about one outcome rather than another, you should take note of your reference frame.