  Here is another example that might help make the de re / de dicto distinction clearer. Suppose \(f\) is the intension of “the tallest person,” and \(g\) is the intension of “the oldest person,” and suppose it happens that, at the moment, these are the same people. Also, let us read \(\Box\) epistemically. It is unlikely we would say that \(\Box [\lambda xy\,x = y]\)(f, g) is the case. We can read \(\Box [\lambda xy\,x = y]\)(f, g) as saying we know that \(f\) and \(g\) are the same. It asserts that under all epistemic alternatives—all the various ways the world could be that are compatible with what we know—\(f\) and \(g\) designate the same object, and this most decidedly does not seem to be the case. However, we do have \([\lambda xy\,\Box (x = y)]\)(f, g), which we can read as saying we know of \(f\) and \(g\), that is, of their denotations, that they are the same, and this could be the case. It asserts that in all epistemic alternative states, what \(f\) and \(g\) designate in this one will be the same. In the setup described, \(f\) and \(g\) do designate the same object, and identity of objects carries over across states.