What is immediately scandalous about Rimbaud's phrase is that it begins 'Je est', 'I is', with the 'I' claiming unelided third person being. 'Am' and 'is' are both primary utterances and they appear not to be interchangeable, to stand for incompatible faces or inflections of being, or non-commuting operators. You cannot imagine the dawn of being in the form of a pure 'is' since this word testifies to a witnessing, and so demands the prior and latent 'am' of the witness. But if 'am' is primary it also demands a prior and latent 'is', the being into which the 'I' emerges, the space that it witnesses, the validation or truth of its am-ness. In English the word 'am' has a further connotation, being the reverse of 'ma' the syllable which Ernest Jones regarded as the universal first syllable a baby utters and hence in most Indo-European languages identified with the mother, with 'mama'. It is also very similar to the Sanskrit mantra 'aum', or 'om', a syllable very well suited to chanting since it contains no hard sounds and can be drawn out for as long as one is able: 'aaauuummmm'. 'Am' is like 'in', is inward pointing, while 'is', or 'ist' or 'est' is like 'out', outward pointing. In a slightly obsolete slang 'I is' expresses a vaguely threatening future tense, as in 'I's a gonna (do something)', an assertion of agency, and certainly there is something of this portentious assertiveness in Rimbaud's phrase. Neither of these inflections of being can dispense with the other, but it seems as though the order in which they are applied makes a significant difference.