 The coherence standards of logic and probability are usually invoked when there are experimental results purporting to violate those standards, particularly in the biases and heuristics literature  (section 7.1).  However, little is said about how and when our reasoning ought to be in accordance with these standards or even what, precisely, the applicable  normative standards of logic and probability are. Stein discusses the logical rule of And-Elimination and a normative principle for belief that it supports, one where believing the conjunction birds sing and bees waggle commits you rationally to believing each conjunct. Yet Stein switches to probability to discuss what principle ought to govern conjoining two beliefs. Why?