It has often been claimed that the by now familiar possible-two rids analysis of propositional attitudes like knowledge and belief which I have advocated since 1962 is unrealistic,1 if not downright mistaken, because it apparently commits us to the assumption of logical omniscience, that is, to the assumption that everyone knows all the logical consequences of what he knows, and analogously for all the other propositional attitudes. Since the assumption of such logical omniscience is obviously mistaken, this commitment seems to constitute a grave objection to the whole possible-worlds treatment of propositional attitudes.