The mind/brain inequality

A unified consciousness may be resolved into multiple perceptual and conceptual components. This suggests that it might be useful to represent experience as a vector in a multi-dimensional space (the `mental state vectorʹ). If it is supposed that a single neuron alone supports minimal consciousness, that vector would exist in a space of minimal dimension. The direction of the vector might then describe both the content of consciousness and the probability of neuronal depolarisation (the `bridging principleʹ). I will outline a mathematical formalism that generalises this description to multiple neurons (and multiple dimensions), while preserving unity. This formalism implies that objective access to subjective information is limited, expressed as the `mind/brain inequalityʹ. The formalism also predicts a correlation of neural activity between remote anatomic sites that is inconsistent with a purely local model of neuronal signalling (Physics 1 (1964) 195). This prediction allows experimental test of the scheme and suggests a role for consciousness in the `bindingʹ (Curr. Opin. Neurobiol. 5 (1995) 520) of perception.