Our Internal Virtual Reality

In Unweaving the Rainbow, Richard Dawkins provides a good scientific explanation of the old philosophical insight (Hobbes's, Berkeley's, Hume's, etc.) that what we usually take to be "reality" is actually a mental construct (at the interface between idealism and materialism), a running simulacrum of reality constructed and played to itself by the brain. (Compare also Bergson's cinematographic theory of the mind). 

This is Dawkins's account of the internal virtual reality that we mistake for the real as such:

Everything that we know about the world outside our skulls comes to us via nerve cells whose impulses chatter like machine guns. What passes along a nerve cell is a voleying of 'spikes', impuses whose voltage is fixed (or at least irrelevant) but whose rate of arriving varies meaningfully. Now let's think about coding principles. how would you translate information from the outside world, say, the sound of an oboe or the temperature of a bath, into a pulse code? A first thought is a simple rate code: the hotter the bath, the faster the machine gun should fire. The brain, in other words, would have a thermometer calibrated in pulse rates. Actually, this is not a good code because it is uneconomical with pulses. By exploiting redundancy, it is possible to devise codes that convey the same information at a cost of fewer pulses. Temperatures in the world mostly stay the same for long periods at a time. To signal 'It is hot, it is hot, it is still hot...' by a continuously high rate of machine-gun pulses is wasteful; it is better to say, 'It has suddenly become hot' (now you can assume that it will stay the same until futher notice).

And, satisfyingly, this is what nerve cells mostly do, not just for signalling temperature but for signalling almost everything about the world.Most nerve cells are biased to signal changes in the world. If a trumpet plays a long sustained note, a typical nerve cell telling the brain about it would show the following pattern of impulses. Before the trumpet starts, low firing rate; immediately after the trumpet starts, high firing rate, as the trumpet carries on sustaining its note, the firing rate dies away to an infrequent mutter; at the moment when the trumpet stops, high firing rate, dying away to a resting mutter again. Or there might be one class of nerve cells that fire only at the onset of sounds and a different class of cells that fire only when sounds go off. Similar exploitation of redundancy — screening out the sameness in the wold —goes on in cells that tell the brain about changes in light, changes in temperature, changes in pressure. Everything about the world is signalled as change, and this is a major economy.

But you and I don't seem to hear the trumpet die away. To us the trumpet seems to carry on at the same volume and then to stop abruptly. Yes, of course. That's what you'd expect because the coding system is ingenious. It doesn't throw away information, it only throws away redundancy. The brain is told only about chantes, and it is then in a position to reconstruct the rest. Barlow [Horace Barlow, "The Coding of Sensory Messages", 1965] doesn't put it like this, but we could say that the brain constructs a virtual sound, using the messages supplied by the nerves coming from the ears. The reconstructed virtual sound is complete and unabridged, even though the messages themselves are economically stripped down to information about changes. The system works because the state of the world at a given time is usually not greatly different from the preceding second. Only if the world changed capriciously, randomly and frequently, would it be economical for sense organs to signal continuously the state of the world. As it is, sense organs are set up to signal, economically, the discontinuities in the world; and the brain, assuming correctly that the world doesn't change capriciously and at random, uses the information to construct an internal virtual reality in which the continuity is restored.

(Richard Dawkins, Unweaving the Rainbow, 260-61)

Now compare this account with that of another contemporary neurologist like Gazzaniga. Michael Gazzaniga's description of the brain's "interpreter", a kind of internal narrator figure which constructs a running narrative of our surrounding world. Gazzaniga's account of the "interpreter" is to be found in The Mind's Past.  In another paper ("La autointeracción, la realimentación cerebral y la realidad como expectativa autocumplida") I point out the parallels between Gazzaniga's account of the brain's fuctioning and a phenomenological-materialist theory of consciousness, that of Herbert George Mead.

As to Berkeley, the substance of his argument is already to be found in his Theory of Vision— it is the mind that constructs objects in the world as mental interfaces for sensory perception, combining the information from diverse senses.

And pushing back further, the essentials of this "theory of reality as virtual reality", stemming from a complex conception of the relationship between perception and reality, is to be found in Hobbes's materialist philosophy (which results, as noted above, in a kind of "idealistic" or "subjectivized" materialism, actually a full-fledged theory of reality as virtual reality). I comment further on Hobbes's theory of virtual reality, or his "phenomenology" avant la lettre if one prefers, in this paper:

"'Lo mismo despiertos, que soñando': Hobbes sobre la virtualidad de lo real"

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