  One well-known linguistic argument against identifying facts with true propositions is closely related to the Ambiguity Response to The Substitution Problem, considered in Section 5.4. Substitution of ‘the fact that p’ for ‘the true proposition that p’, or vice versa, produces peculiarities such as “John believes the fact that Obama is president”, or Harman’s (2003) “The true proposition that fires are hot makes it the case that fires are hot.” If facts were true propositions, so it is argued, one would expect the substitutions to preserve truth.