and T. S. Eliot had previously approached the subject of fragmentation of human experience: while Eliot was writing, and Pound editing, The Waste Land, Pound had said that he looked upon experience as similar to a series of iron filings on a mirror. Each filing is disconnected, but they are drawn into the shape of a rose by the presence of a magnet. The Cantos takes a position between the mythic unity of Eliot's poem and Joyce's flow of consciousness and attempting to work out how history (as fragment) and personality (as shattered by modern existence) can cohere in the "field" of poetry. Nevertheless, there are indications in Pound's other writings that there may have been some formal plan underlying the work. In his 1918 essay A Retrospect, Pound wrote "I think there is a 'fluid' as well as a 'solid' content, that some poems may have form as a tree has form, some as water poured into a vase. That most symmetrical forms have certain uses. That a vast number of subjects cannot be precisely, and therefore not properly rendered in symmetrical forms". Critics like Hugh Kenner who take a more positive view of The Cantos have tended to follow this hint, seeing the poem as a poetic record of Pound's life and reading that sends out new branches as new needs arise with the final poem, like a tree, displaying a kind of unpredictable inevitability. Another approach to the structure of the work is based on a letter Pound wrote to his father in the 1920s, in which he stated that his plan was: A. A. Live man goes down into world of dead. C. B. 'The repeat in history.' B. C. The 'magic moment' or moment of metamorphosis, bust through from quotidian into 'divine or permanent world.' Gods, etc. [The letters ABC/ACB indicate the sequences in which the concepts could be presented.] In the light of cantos written later than this letter, it would be possible to add other recurring motifs to this list, such as: periploi ('voyages around'); vegetation rituals such as the Eleusinian Mysteries; usura, banking and credit; and the drive towards clarity in art, such as the 'clear line' of Renaissance painting and the 'clear song' of the troubadours. The poem's symbolic structure also makes use of an opposition between darkness and light. Images of light are used variously, and may represent neoplatonic ideas