Yli-Vakkuri (2018) offers a deductive argument for Content Externalism that primarily appeals to two main principles he says should be adopted by all parties to the debate. Sawyer (2018) criticizes this argument on the grounds that there are internalist theories that are not consistent with the two principles he offers, although she takes no issue with the derivation itself. While Sawyer’s critique is insightful and largely correct, there is a more fundamental problem with the original argument. The formal proof given in the original paper begs the question. The informal argument is enthymematic, and all the possible valid reconstructions require assumptions that can be legitimately rejected by content internalists. This is significant to point out as someone might think that the internalist views that Sawyer says are not consistent with the two principles that drive Yli-Vakkuri’s argument can be successfully challenged and thereby the original argument defended.
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