 YVH do not deny that narrow content assignments are possible, but they do argue that there is unlikely to be any narrow content assignment that plays a theoretically useful role. A plausible minimal requirement for a narrow content assignment to be useful is that it be “truth conditional,” in the following sense: for any thought, the content assigned to that thought should determine, relative to the circumstances in which the thought actually occurs, the truth value that the thought actually has. One of their central arguments, the “parameter proliferation argument,” attempts to show that the only way for a narrow content assignment to be truth conditional is for it to employ a problematic notion of content (specifically, a notion of content with inappropriate “parameters,” in a sense to be explained next).