Text 24. It is not to be leveled as a criticism that, because the craft should have general rules, there are propositions that cannot be taken under either of these two considerations (namely, those whose subjects are impossible, as in “the co-creator is impossible”, and “every impossible is non-existent”).  Because we say: No one claims to limit all propositions to the essentialist and the externalist. They do however claim that propositions used in the sciences are used for the most part under one of these two considerations, so they therefore set these readings down and extract their qualifications so they may thereby benefit in the sciences. The qualifications of the propositions that cannot be taken under either of these two considerations are not yet known; the generalization of rules is only to the extent of human capacity.  (Tahtânî 1948: Tahrîr 95.pu–96.11) 