The nested networks of brains and minds

The reductionist approach to the brain shows promise of revolutionizing our ideas about what single neurons can do. A spine on a cortical pyramidal cell is about the size of a single Escherichia coli, and if the internal machinery of a spine is anything like as well organized as that of E. coli, the whole pyramidal cell with its 5000 spines must be capable of computations an order of magnitude more complex than those demanded of the neurons used for current models of the brain. These computations might enable single neurons to detect spatiotemporal patterns, i.e. Hebb's 'phase sequences'. Reductionism is apparently limited because its drive is to look for explanations at lower levels in the organizational tree. For this purpose it often uses isolated preparations in which such lower levels can be studied but higher levels cannot, because they have been thrown down the sink. Reductionism will never lead us to understand organization and interaction in parts discarded or ignored, and this must include the interactions between individual human minds that are crucial for understanding human society. Our brains possess a 'commentary system', a mechanism that can make reports on the internal status of some parts of the brain. This makes possible networks of minds, and the present meeting is such a network whose interactions are being recorded for posterity. On a grander scale such networking creates a cultural forum where communal goals and purposes are formulated, disseminated, modified, and often perpetuated in lasting form. The resulting group behaviour has obvious survival value, and is perhaps the feature that distinguishes humans most clearly from other species.