image is taken from the cover of Philip Fisher's (1998) important book:
Rainbow, and the Aesthetics of Rare Experiences. Harvard University
Press. A rainbow is, of course, a "real presence," in that it has no objective
existence or location in space in itself, but - like the mystic 3-D shapes
appearing as one looks over the array of dots in random dot stereograms
- it only makes a unique appearance to a unique individual (as the diagram
shows) in the dynamics of interaction occurring between them and the sunlight
from behind them. KCC International took the rainbow as the motif for its
123 Conference in Canterbury, in July 2002.
"If, for the first trend [romantic individualistic subjectivism], language is an ever-flowing stream of speech acts in which nothing remains fixed and identical to itself, then, for the second trend [modernist abstract objectivism], language is the stationary rainbow arched over the stream" (Voloshinov, 1986, p.52 in Marxism and the Philosophy of Language).
"Look at a rainbow... Is it really there?... [I]f you walked to to the place where the rainbow ends, or seems to end, it certainly would not be 'there'. In a word, reflection will assure you that the rainbow is the outcome of the sun, the raindrops and your own vision" (Owen Barfield, 1965, p.15 in Saving the Appearances: a Study in Idolatory).