Originally uploaded by catmachine
The Slow-switching Slowdown Showdown
The point of this paper is to raise a puzzle for cognitive content externalism. Central to the kind of externalism I wish to raise a puzzle for is a commitment to a thesis of slow switching: were Oscar stealthily transplanted on Twin Earth, replacing Twin Oscar, the thought contents expressed by Oscar’s “water” utterances would switch slowly from being thoughts of H2O to being thoughts of XYZ. The puzzle I want to raise centers on the question of how the externalist can account for the rate of slow switching. What’s especially puzzling about this question of rate is best brought out by considering certain natural extensions of externalism to contents concerning time and a modification of the Twin Earth thought experiment involving Slow Earth—a version of XYZ-covered Twin Earth where (just about) everything takes hundred times longer to occur on Slow Earth. It is a natural extension of externalism to time concepts to hold that Oscar and his counterpart on Slow Earth, Slow Oscar, express different thoughts by utterances employing temporal vocabulary such as “day,” “hour,” and “minute.” A further natural extension of externalism is to hold that if Oscar were stealthily transplanted to Slow Earth, not just his “water”-related concepts would slowly switch their contents, so would, e.g., his “hour”-related concepts. The question at the heart of my puzzle for the externalist is this: How long would slow switching take on Slow Earth? If everything is a hundred times slower on Slow Earth compared to non-slowed Twin Earth, then if slow switching takes a year on Twin Earth, it takes 100 years on Slow Earth (which is, of course, just one Slow Earth year). However, as I shall argue, it raises certain problems for externalists to hold that even slow switching is slowed down on Slow Earth. The core problem raised, I will argue, is that the externalist, in holding that slow switching slows on Slow Earth, is led to embrace a contradictory account of what the supervenience base is for wide-content temporal thoughts.