I consider Symons's book indispensable to a genuine appreciation of Eliot's poetry.
I strongly recommend it to anyone coming fresh to Eliot's poetry.
As for this post, it's just that the observation on Gerard de Nerval came handy.

From: Chokh Raj <[log in to unmask]>
To: [log in to unmask]
Sent: Saturday, July 30, 2011 7:27 PM
Subject: TS Eliot vis-a-vis Symons's 'The Symbolist Movement in Literature'

TS Eliot vis-a-vis Symons's 'The Symbolist Movement in Literature'
"Symons defined symbolism as a form of expression for an unseen reality apprehended by the consciousness. The significance of the Symbolist Movement in French poetry lay for him in the revolt against exteriority, rhetoric, and scientific materialism. He wrote of Gerard de Nerval -- who found his most precious and uninterrupted solitude in the crowded and more sordid streets of great cities -- as possessing a state of 'double consciousness'; of his unique 'narrative of madness' in which are revealed the hidden links of distant and divergent things; and of his illusions of the imagination and of the nerves." -- Manju Jain, TS ELIOT: SELECTED POEMS, Delhi: Oxford University Press, 1998
Reminded of 'Prufrock's Pervigilium'. So it was all, for Eliot, only a matter of adapting a literary convention, and not a matter of personal nerves and split personality.