In a manner that asserts something confidently; in a way that makes positive claims or statements.
From 'assertorial' + '-ly' (adverbial suffix). The adverbial form adds the manner dimension to the adjective, describing how something is done or stated.
A philosopher writing about logic might use 'assertorially' to distinguish between how we state facts ('assertorially') versus how we propose possibilities—it's technical language for the moment when claims become bold rather than tentative.
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