Abstract

This paper advances our understanding of the norms of assertion in two ways. First, I evaluate recent studies claiming to discredit an important earlier finding which supports the hypothesis that assertion has a factive norm. In particular, I evaluate whether it was due to stimuli mentioning that a speaker’s evidence was fallible. Second, I evaluate the hypothesis that assertion has a truth-insensitive standard of justification. In particular, I evaluate the claim that switching an assertion from true to false, while holding all else objectively constant, is irrelevant to attributions of justification. Two pre-registered experiments provide decisive evidence against each claim. In the first experiment, switching from mentioning to not mentioning fallibility made no difference to assertability attributions, thereby disproving the criticism concerning fallibility. By contrast, switching an assertion from true to false decreased the rate of assertability attribution from over 90% to less than 20%, thereby replicating and vindicating the original finding supporting a factive norm. In the second experiment, switching an assertion from true to false decreased the rate of justification attribution from over 80 to 10%, thereby undermining the hypothesis that assertion’s standard of justification is truth-insensitive. The second experiment also demonstrates that perspective-taking influences attributions of justification, and it provides initial evidence that the standard of justification for assertion is stricter than the standard for belief.