 Unsurprisingly, norms or rules for (rational) reasoning receive a lot of attention. Prime examples are inference rules such as modus ponens or the law of non-contradiction. Purely formal rules would arguably be too weak for the purposes of strong CD normativism; normative inferentialists such as Brandom (1994; 2000) or Peregrin (2008) therefore include norms governing material implication among the content determining rules. In general, principles governing epistemic rationality (as, for instance, formalized in Bayesian epistemology) are further examples, and for those who hold that there can be good practical reasons for belief, principles of practical reasoning are also  relevant.[56]