n. The doctrine that states of the mind and states of the brain are identical.
the GNU version of the Collaborative International Dictionary of English
n. The doctrine taught by Schelling, that matter and mind, and subject and object, are identical in the Absolute; -- called also the system of identity or doctrine of identity.
The Century Dictionary and Cyclopedia
n. The system or doctrine of identity: a name applied to the metaphysical theory of Schelling. See identity.