Almost the Quote I'm Looking For

I'm pretty sure Paul Goodman says this somewhere else slightly better, or at least more concisely, but I can never find it:

I can put my difficulty as a teacher as follows: It is impossible to convey that Milton and Keats were for real, that they were about something, that they expected that what they had to say and the way in which they said it made a difference. The students can (not brilliantly) tell you about the symbolic structure or even something about the historical context, though history is not much cultivated; but, if one goes back more than thirty years, they don't have any inkling that these poets were writers and in a world. (Compulsory Mis-education, p. 142.)