 In particular, c knows all theorems (letting \(\Gamma=\emptyset\)), and knows all the logical consequences of any formula that the agent knows (letting \(\Gamma\) consist of a single formula). The concern here is that finite agents are constrained by limits on their cognitive capacities and reasoning abilities.  The account of knowledge and belief that epistemic logic seems committed to involves superhuman abilities like knowing all the tautologies. Thus, the concern is that epistemic logic is simply unsuited to capturing actual knowledge and belief as these notions figure in ordinary human life.