Summary: Narrow content functionalism claims that the contents of beliefs are determined by their causal profile. If two belief tokens are of the same causal type, they are of the same semantic type. However, Taylor argues that de dicto semantic types do not supervene on causal types, due to multiple realizability. He establishes this with the thought experiment of “fraternal twin earth”, where things are functionally identical but molecularily different.
Comment: This paper shows how Putnam's "twin earth" thought experiment needs to be modified to address narrow content functionalism. Suited to higher-level mind and language courses. Best taught after some more introductory readings on the topic, as those not already familiar with some of the elements may become lost.