requires a mind as subtle and penetrating as his own to understand the
mystic meanings scattered throughout the poem. They elude the ordinary
reader by their abstraction and delicacy of distinction, but they are
far from vague. It was his design to write prose metaphysical essays on
the nature of Man, which would have served to explain much of what is
obscure in his poetry; a few scattered fragments of observations and
remarks alone remain. He considered these philosophical views of Mind
and Nature to be instinct with the intensest spirit of poetry.

More popular poets clothe the ideal with familiar and sensible imagery.
Shelley loved to idealize the real--to gift the mechanism of the
material universe with a soul and a voice, and to bestow such also on
the most delicate and abstract emotions and thoughts of the mind.
Sophocles was his great master in this species of imagery.

I find in one of his manuscript books some remarks on a line in the
"Oedipus Tyrannus", which show at once the critical subtlety of
Shelley's mind, and explain his apprehension of those 'minute and remote
distinctions of feeling, whether relative to external nature or the
living beings which surround us,' which he pronounces, in the letter
quoted in the note to the "Revolt of Islam", to comprehend all that is
sublime in man.

'In the Greek Shakespeare, Sophocles, we find the image,

Pollas d' odous elthonta phrontidos planois:

a line of almost unfathomable depth of poetry; yet how simple are the
images in which it is arrayed!