 Different principles lend themselves more or less well to these two readings. \(C\)- and \(B\)-type principles can be interpreted as either synchronic or diachronic principles on account of the fact that they make explicit claims as to what an agent ought, may or has reason to believe or disbelieve given her other beliefs. The \(W\)s, by contrast, are most plausibly read as synchronic principles. Such principles do not, in and of themselves, instruct the subject which inferences to make. Rather, they tend to proscribe certain patterns of belief (and, perhaps, disbelief) or distributions of degrees of belief.