Artificial Consciousness: Symbol Manipulation

I left two items of unfinished business in the last post of this series:

• the distinction between direct reaction to a stimulus and what I called reaction through symbols and
• whether an intelligence must understand that it is reflecting on its own symbols in order to be considered conscious.

To illustrate these ideas, as well as to marvel at the symbol-processing abilities of our brains, let’s consider what happens when I ask you, “How are you feeling today?”

Pushed along by the flapping of my vocal chords, tongue and lips, some air molecules bump into other air molecules until the chain reaction reaches your ear, where the bumping around eventually causes your stapes (“stirrup”) to move like a piston against your cochlea.

The movement of the stirrup bone in the video reminds me of a telegraph. At that point in the chain reaction, my words as well as all the emotion behind them are encoded in symbolic form, much like a computer program. We’re not down to the level of ones and zeroes, but the up-and-down motion of the stirrup brings us darn close.

From there, an elaborate decoding begins.

1. The 20,000 hair cells in your organ of Corti parse the pitches from the waves that the stirrup creates.
2. Adjacent cells transform those hair-vibrations to impulses on your auditory nerves. You could spend 1,000 years inspecting the chemical reactions that are taking place around those nerves and you would never suspect that they were a symbolic representation of “How are you feeling today?” but that is exactly what they are.
3. Those nerves stimulate other nerves in various areas of your brain and the resulting pattern of nerve-firings as match, to various degrees, other patterns that you have stored over the years — specifically the patterns for the words I used as well as my tone of voice.
4. The “tickling” of those matching patterns produces the effect that you know what I said.

Although this is wondrous in the extreme, we do not need to resort to ghosts and spirits to understand it. No supernaturalist I know claims to hear other people with his spirit. It is a purely physical process.

During that process, symbols are built from other symbols, in layers of increasing sophistication: movement of the stirrup bone, movement of hair cells, electrical pulses along the nerves, and finally patterns of neural activity throughout your brain. None of that was my actual speech or the human emotion behind it; it was all symbolic representation of my speech and emotion.

So, returning to the first question for this post, where does direct reaction leave off and symbol-processing begin? It’s not clear, is it? If we accept that unconscious, machine-like reaction is a simple response to a stimulus, then which links in our chain of events were machine-like and which were something more? To me, they are all purely mechanistic. What makes your hearing my question a conscious act is the sophistication of the machinery. Once more we see that consciousness is a matter of degree.

And what about the second question? Does a conscious being have to understand that it is reflecting on its own symbols? I suggest it does not. Until the last couple of centuries, almost none of the mechanism of hearing was understood, People were unaware of the symbols, much less their reflection on them. Yet, people were conscious. Even now, we are cannot be aware of the lower levels of symbol-processing, no matter how much we try. (Can you feel your stirrup bone hammering up and down?  Are you aware of individual neural firings?)

In fact, of all the many symbol-layers involved in as simple an act as hearing me ask, “How are you feeling today?” the only one we’re able to access is the top one — the layer of the most sophisticated symbols. No wonder it seems like it couldn’t possibly arise from a machine-like process! We’re unable to perceive the machine even though we know it’s there!

Next time: Does the substrate for the symbols matter?