The Supramundane Path

This is a genuinely striking structural point: of the eight classical meditative levels, only the very highest — the sphere of neither perception nor non-perception — is permanently barred from ever housing the noble path itself, even though it stands, in the ordinary cosmological ranking, above every other formless sphere. T1606 explains why: the noble path requires sufficiently clear, sharp perception to actually take the four truths as its object and directly penetrate them, but by the time meditative refinement has advanced all the way to this final sphere, perception itself has become so attenuated, so nearly indistinguishable from its own absence, that it can no longer sustain the kind of vivid, incisive discernment the path's own direct realization demands. Being the most refined attainment available does not, in other words, make it the most useful for actually breaking through to liberation — a sobering point against simply equating "more subtle" with "more advanced on the path to awakening."

T1606 works out this restriction as a four-cornered analysis worth stating explicitly. Someone already free of form-realm desire, resting merely at the not-yet-attained level, can be free of that desire without being able to enter this attainment at all. A noble one who has already mastered the fourth dhyāna, without specifically seeking rebirth in the formless realm, can — through disenchantment and continued cultivation of that same fourth dhyāna, proceeding by way of the path of further advancement — gradually enter this still, liberated attainment. That same practitioner, actively seeking freedom from desire and proceeding instead by way of the path that actually severs the corresponding fetters, can likewise gradually enter it. And every remaining combination falls outside all three of these specific cases. The underlying reason a being already reborn into the formless realm rarely manifests this attainment, T1606 adds, is not incapacity but simple lack of motivation: already resting in that realm's own profoundly still ripened result, such a being feels little pull to exert the further deliberate effort the attainment of cessation would require — it is a genuine option, on this account, simply one seldom actually taken up once the formless realm's own attainment has already been reached.