He knows A.
Of this he can express only B in words.
B is less than A.
But he could or would not even have expressed B had he not known A, or at any rate something between B and A.
That is, he would not have expressed even B had he known only B.
He is saying that it is not only sufficient, but also necessary, for his expressing what he does express that he knows more than he does express.
Anthony Stadlen
Dear Anthony Stadlen,
Why? can you imagine? and what is B? i.e. what has he expressed in words? [I believe he was responding to the question "Do you believe in God?"]
These may be impossible questions. Is he hinting that he has had an encounter of I don't know what kind? that he was enjoined not to divulge, presumably by God, the nature of this encounter?
Carolyn