I Consciousness: The Neuro -philosophical Tradition

1. I Consciousness: The Neuro-philosophical Tradition • Consciousness – a state too obvious and so difficult to define - remains a fascinating mystery to the physiologist and the philosopher.

2. Consciousness: The Philosophical Tradition • Plato – Cause and effect the same “My notion would be, that anything which possesses any sort of power to affect another, or to be affected by another, if only for a single moment, however trifling the cause and however slight the effect, has real existence; and I hold that the definition of being is simply power.”

3. Aristotle • Augustine • Aquinas • Descartes (Dualism) • Spinoza (complexity in thinking; the correlate in Thought of the extraordinarily high complexity of the human body in Extension).

4. Rene Descartes 1. The mind-brain dualism. 2. Cogito ergo sum

5. Cartesian Dualism • A total fragmentation of Reality : • subject and object • man and world • Matter and Spirit • two separate realms of mind and matter. • matter as dead and completely separate from ourselves. • Cogito ergo sum - identity with their mind • Levinas : Critique of being

6. Determinism • Libertarianism • Compatibilism • The Indian Perspective

7. 2008 – Integrated Information Theory • Neuroscientist Giulio Tononi • Currently accepted as one of the most compelling explanations about what consciousness is. • for consciousness to exist, it must have “cause-effect” power on itself. (Panpsychism).

8. Neurologists have made enormous advances in understanding the biological process that might be equivalent to consciousness or “mind”. They have revealed that the individual junctions, or synapses (above), between nerve cells in the brain are far more sophisticated than the “switches” in the most advanced computers. Each synapse is remarkably adaptable in its responses, and each nerve cell behaves like a miniature processor. Consciousness arises from the simultaneous functioning of billions of nerve cells communicating via trillions of synapses. The question is, how does that occur?

9. While theologians once saw consciousness, or the soul, as God-given, some modern neurologists maintain that it is no more than a by-product of the physical and chemical processes that take place in the brain. Consciousness emerges from interactions between these processes in the same way that a rainbow, although beautiful and seemingly purposeful, is merely the result of the interplay between light and water droplets.

10. A “typical” neuron in the human cortex has a diameter of less than one micrometer and is usually contacted by thousands of other neurons. An electrical impulse moves down the “sending” neuron's long axon toward the small swellings on its terminals. Here, the impulse triggers the release of tiny packets (or vesicles) of neurotransmitter chemicals into a small gap (the synaptic gap) between the sending cell and the branch-like projections (dendrites) of the receiving cell. These neurotransmitters diffuse across the gap and unlock chemical gates on the surface of the receiving cell, and this event causes the receiving cell to fire, sending an impulse down its own axon.

11. This micrograph clearly demonstrates the complex organization of neurons within the human brain. Neurons, however, are not the only type of cells in the central nervous system. They are, in fact, greatly outnumbered by glial cells, which perform the brain’s housekeeping functions, notably nourishing the neurons and holding them in place.

12. The number and complexity of the interneurons in the central nervous system increased over evolutionary time. The organization of networks allowed sensory information to be processed before being sent to muscles. An incoming impulse can diverge and pass to several motor neurons (left); impulses from several sources can converge on a single interneuron, which fires when it receives a number of inputs (top right); and an interneuron can feed an impulse back to itself, creating a loop (bottom right).

14. Unconsciously Conscious • We unconsciously decide to act before we consciously decide to do so. Hence voluntary acts seem to be not really free and spontaneous; rather they seem to be preceded and triggered by unconscious events. There are electrical changes in the brain which really initiate the action, before we consciously decide to act. It would mean that our “free” acts are rather consequences of unconscious events than acts caused by free agents. However, free will might still be relevant by having the capacity of vetoing the unconsciously initiated act.

15. Free Will • materialistic determinism vs and metaphysical dualism • whether we are completely defined by deterministic laws of nature, or have some independence in making choices and actions?

16. In the traditional view of conscious will and free will, one would expect conscious will to appear before, or at the onset, of the RP, and thus command the brain to perform the intended act. But an appearance of conscious will 550 msec. or more before the act seemed intuitively unlikely. It was clearly important to establish the time of the conscious will relative to the onset of the brain process (RP); if conscious will were to follow the onset of RP that would have a fundamental impact on how we could view free will.

17. Oscilloscope ‘clock’. Spot of light revolves around periphery of screen, once in 2.56 sec. (instead of 60 sec. for a sweep-second hand of a regular clock). Each marked off ‘second’ (in the total of 60 markings) represents 43 msec. of actual time here. The subject holds his gaze to the centre of the screen. For each performed quick flexion of the wrist, at any freely chosen time, the subject was asked to note the position of the clock spot when he/she first became aware of the wish or intention to act. This associated clock time is reported by the subject later, after the trial is completed.

18. Diagram of sequence of events, cerebral and subjective, that precede a fully self-initiated voluntary act. Relative to 0 time, detected in the electromyogram (EMG) of the suddenly activated muscle, the readiness potential (RP) (an indicator of related cerebral neuronal activities) begins first, at about –1050 ms. when some pre-planning is reported (RP I) or about –550 ms. with spontaneous acts lacking immediate pre planning (RP II). Subjective awareness of the wish to move (W) appears at about –200 ms., some 350 ms. after onset even of RP II. However, W does appear well before the act (EMG). Subjective timings reported for awareness of the randomly delivered S (skin) stimulus average about –50 ms. relative to actual delivery time.

20. The results show that the brain process to prepare for this voluntary act began about 400 msec. before the appearance of the conscious will (W) to act. Libet suggests that the actual difference in times is probably greater than the 400 msec., because the actual initiating process in the brain probably starts somewhere in an unknown area which activates the supplementary motor area in the cerebral cortex. The source of RP is the supplementary motor area. The conclusion is that our conscious voluntary acts are actually initiated unconsciously

21. What is the Role of Consciousness? • Is our conscious will merely a spectator in our voluntary acts? Is there any significant role for the conscious will? • …conscious will (W) does appear about 150 msec. before the muscle is activated, even though it follows onset of the RP. An interval of 150 msec. would allow enough time in which the conscious function might affect the final outcome of the volitional process…. Potentially available to the conscious function is the possibility of stopping or vetoing the final progress of the volitional process, so that no actual muscle action ensues. Conscious-will could thus affect the outcome of the volitional process even though the latter was initiated by unconscious cerebral processes. Conscious-will might block or veto the process, so that no act occurs.

22. The Quantum Correlation of mind and matter. • The Indian Perspectives • Conscious wish: Beyond dualism