Comment by TKoL on Is the failure of substitutivity in an intensional context simply due to a lack of clarity in terms of the identity operator?

You might reword Lois lanes belief as "Lois believes the person she recognises as superman can fly." Then it becomes apparent that you can't swap in Clark Kent for "the person she recognises as superman" - but crucially, once she finds out they're the same person, suddenly you CAN swap it in.