Crowley’s understanding of his own progress in the Order is interesting, but the question is whether he invented the term
Ipsissimus for 10=1 or not. One way to judge the plausibility of Pasi’s assertion is to look at how other Rosicrucian or Golden Dawn orders have taken it without question. If Crowley is indeed the inventor of the term, then his influence on all subsequent such orders is extremely profound, even on those very hostile to him, and which view him as a fraud and charlatan, who certainly never attained the Grade he himself named.
I find Pasi’s notion, essentially an argument from silence, dubious because of this, among other things.
(the strength of arguments from silence or "absence of evidence is evidence of absence", rests on whether we have reason to think there should be evidence (references), and there is not, or whether there is enough evidence overall to say with a high degree of confidence that the absence of evidence in a particular case is evidence of its absence. In this case, Crowley appears to be merely the first to put it in print; there is no evidence that he invented it, he never claims to, and there is good reason to think that the secrecy that shrouded the Third Order explains the absence of evidence for the term before 1909 (like the term "A.'.A.'." before 1906))
I don’t know much about Case, so I’ve had to look around. In his attitude to Crowley, Paul Foster Case is not completely dismissive or overtly hostile. See his article, “To Our Members”, first published in the
Wheel of Life, autumn equinox, 1936:
“
We would not recommend Aleister Crowley as a guide in practical occultism. Yet his book 777 is the finest thing of its kind.”
http://www.bota.org/assets/2007/12/15/portico-7-1.pdf
Case was never a member of the
Stella Matutina, that I can find. He was, however, a very active member of the Thoth-Hermes Temple of the
Alpha et Omega in Chicago. This was Mathers’ group, of course. Case joined in 1918, and in May 1920 took his 5=6. He became Praemonstrator of the Temple in February, 1921, and resigned simultaneous to being expelled by Moina Mathers in December, 1921. As a Second Order member, and Praemonstrator, Case probably had access to all the written information there was about Alpha et Omega; other information might have come from Brodie-Innes, the head of the Order after MacGregor Mathers died, and Moina before the expulsion, with both of whom Case was in correspondence. So, while he knew Crowley’s writings, he also knew the old GD through Mathers and the Alpha et Omega.
This information comes from, among other places which tell the story, Lee Moffitt, in his convenient “Case timeline” (1997). Moffitt also provides a few bits of information about Case’s knowledge of Crowley:
http://kcbventures.com/pfc/documents/timeline.pdf
1926-1927: Case
“… reconstructed A.’.O .’. rituals from a combination of his memory and a copy of the Equinox”.
Moffitt’s single source for this (10) is a “Private communication, An anonymous source”, but this source’s reliability is not sure, since in the same timeline at the end, under “Other Items”, Moffitt cites the Anonymous private communication for the information that Case was initiated to third degree OTO by Crowley himself, “probably early 1917 to mid-1918”, but resigned later out of “dissatisfaction.”
This appears to be unsubstantiated rumour, from what I can find. Martin Starr, in
The Unknown God, writes of Case’s involvement with C.S. Jones and the “Universal Brotherhood” (U.B.; see pp. 116-118), but makes no mention of any O.T.O. association.
For the O.T.O. connecton, Moffitt also cites the “HOGD Biography page” for Paul Foster Case. I can’t find this HOGD page; it is an old reference, perhaps long dead – but there is nothing about Case’s putative membership in the O.T.O. on this other (same?) “Hermetic Order of the Golden Dawn” biography page –
http://www.golden-dawn.com/eu/displaycontent.aspx?pageid=160-biography-paul-foster-case
To sum up, Case kept the old GD Grade system, which he believed to be extremely ancient. He did not follow the A.’.A.’. Golden Dawn grades, which suppressed Theoricus at least by March, 1910 (in Liber XIII). If he did not know the name of 10=1 from his three-year happy association with Alpha et Omega, or subsequent correspondence with people who knew more than he did, he could indeed have taken it from 777, column CXXI, or from the “Diagram of the Paths and Grades” in
Equinox I,2, p. 243. But I stand by what I said earlier – he believed it was the correct, ancient Rosicrucian name for this Grade, and had no reason to believe it was Crowley’s invention, even if the only place he ever saw it named was in Crowley.