Here’s a good, though old, Discover Magazine article about self organizing, evolved machines that is worth a read.
Evolving a conscious machine
Strangely, Thompson has been unable to pin down how the chip was accomplishing the task. When he checked to see how many of the 100 cells evolution had recruited for the task, he found no more than 32 in use. The voltage on the other 68 could be held constant without affecting the chip’s performance. A chip designed by a human, says Thompson, would have required 10 to 100 times as many logic elements—or at least access to a clock—to perform the same task. This is why Thompson describes the chip’s configuration as flabbergastingly efficient.
It wasn’t just efficient, the chip’s performance was downright weird. The current through the chip was feeding back and forth through the gates, swirling around, says Thompson, and then moving on. Nothing at all like the ordered path that current might take in a human-designed chip. And of the 32 cells being used, some seemed to be out of the loop. Although they weren’t directly tied to the main circuit, they were affecting the performance of the chip. This is what Thompson calls the crazy thing about it.
Thompson gradually narrowed the possible explanations down to a handful of phenomena. The most likely is known as electromagnetic coupling, which means the cells on the chip are so close to each other that they could, in effect, broadcast radio signals between themselves without sending current down the interconnecting wires. Chip designers, aware of the potential for electromagnetic coupling between adjacent components on their chips, go out of their way to design their circuits so that it won’t affect the performance. In Thompson’s case, evolution seems to have discovered the phenomenon and put it to work.
It was also possible that the cells were communicating through the power-supply wiring. Each cell was hooked independently to the power supply; a rapidly changing voltage in one cell would subtly affect the power supply, which might feed back to another cell. And the cells may have been communicating through the silicon substrate on which the circuit is laid down. The circuit is a very thin layer on top of a thicker piece of silicon, Thompson explains, where the transistors are diffused into just the top surface part. It’s just possible that there’s an interaction through the substrate, if they’re doing something very strange. But the point is, they are doing something really strange, and evolution is using all of it, all these weird effects as part of its system.
In some of Thompson’s creations, evolution even took advantage of the personal computer that’s hooked up to the system to run the genetic algorithm. The circuit somehow picked up on what the computer was doing when it was running the programs. When Thompson changed the program slightly, during a public demonstration, the circuit failed to work.
All the creations were equally idiosyncratic. Change the temperature a few degrees and they wouldn’t work. Download a circuit onto one chip that had evolved on a different, albeit apparently identical chip, and it wouldn’t work. Evolution had created an extraordinarily efficient, utterly enigmatic circuit for solving a problem, but one that would survive only in the environment in which it was born. Thompson describes the problem, or the evolutionary phenomenon, as one of overexploiting the physics of the chips. Because no two environments would ever be exactly alike, no two solutions would be, either.
Cases like this seem to justify Turing’s argument that ‘machines can sometimes surprise me’, though Turing was quite far from thinking along these lines.