Representation / Memory

Let's envision this as a story. There's a kind of mad scientist in his basement fiddling around with electronics while some high school kids watch him and ask questions.

The mad scientist has 10 cards with the numbers 0-9 written on them. He shuffles the cards and then places a randomly chosen card in front of a video camera connected to his electronic circuit board. There is an audio speaker also connected to the circuit, and that speaker immediately emits a sound that sounds like "Six." Indeed, the 6 card was displayed for the video camera. The mad scientist allows the kids to try it themselves with various cards, again and again. The audio speaker always gives the correct number.

Well, it's a neural network. There are several hundred pixel inputs coming from the video camera and flowing into the circuit board. The main neural network is trained to receive these inputs and then output just one of 10 possible outputs.

Each of those outputs flows into the audio circuit which has 10 different audio recordings representing the numbers 0-9, so the neural network output activates the proper audio recording which is sent to the speaker as the final output.

Now the question is: How does the system "know" the number six?

Some people would argue that the system doesn't really know anything. It's just a bunch of wires and electrical currents. But the mad scientist insists that his system really knows the number six as truly as any of the students do, and in the same way.

Here's the point: The system knows 6 insofar as it produces output that we all associate with 6 whenever it gets input associated with 6. This is the basic principle, that we know things in terms of their inputs and outputs.

Indeed, if you examine the mad scientist's electrical circuit, you won't see anything resembling a 6. There's nothing but a bunch of wires connecting up little nodes we call neurons.

The same thing is true, of course, when we look inside a human brain. The brain is nothing but neurons connected up with each other, and there's nothing resembling the number 6. So how do we know the number 6?

We know 6 insofar as our brains tend to produce output commonly associated with 6 whenever it receives sensory input associated with 6. That's all!

Some people will complain that the audio controller chip contained audio representations of the sounds of the numbers 0-9. So there really is representation in the brain after all!

But wait - is there any sound in the audio chip? No. All the audio chip contains are digital instructions for how the audio speaker can make various sounds. It's still nothing more than electricity flowing through myriad branching channels. This flow of electricity activates and deactivates a magnet in extremely rapid succession, which causes a diaphram to vibrate, which makes actual sound waves in the air. It's all just energy flow! There's no representation at all in the system.

Human brains also contain neural constructs telling you how to move your mouth, tongue throat etc. in order to say "Six" out loud. These neural constructs are just like the audio controller chip insofar as they just channel neural-electric energy flow. There really isn't any sound in your head.