'functional consciousness' or 'karmically inoperative consciousness', is a name for such states of consciousness as are neither karmically wholesome (kusala), nor unwholesome (akusala), nor karma-results (vipāka); that is, they function independently of karma.
Thus are also called all those worldly mental states in the Arahat which are accompanied by 2 or 3 noble roots (greedlessness, hatelessness, undeludedness), being in the Arahat karmically neutral and corresponding to the karmically wholesome states of a non-Arahat (s. Tab. 1-8 and 73-89), as well as the rootless mirth-producing (hasituppāda) mind-consciousness-element of the Arahat (Tab. 72); further, that mind-element (mano-dhātu) which performs the function of advertence (āvajjana) to the sense object (Tab. 70), and that mind-consciousness-element (manoviññāna-dhātu) which performs the functions of deciding (votthapana) and advertence to the mental object (Tab. 71).
The last-named 2 elements, of course, occur in all beings.
Together with karma-resultant consciousness (vipāka) it belongs to the group of 'karmically neutral consciousness' (avyākata). See Tab. I (last column). - (App.).