Electrical Engineering Geekery!

Or: One Step Closer to Skynet!

OK, this is just cool. As most of you know I'm an electrical engineer, so I find this kind of thing fascinating.

We've found the fourth fundamental electrical component.

Up until recently we've had just three: The resistor, the capacitor, and the inductor. Each works with the forces of electricity - charge, current, voltage, and magnetic flux - differently, and each acts in a complimentary manner with the others to allow us to do interesting and useful things. Back in 1971 a UC Berkely engineer predicted that there should be a fourth component, just to fulfill the symmetry of the forces of electricity. He predicted the behavior of that fourth component based on the behaviors of the other three, and he even tried to make one by combining the other three and some transistors, but ended up giving up.

He did, however, name the component: the memristor.

The really interesting thing that he predicted about the memristor is what separates it from the other three fundamental components, and is the source of its name - the memristor has a memory that is fundamental to its existence. It would "remember" what happened to it last. None of the other three components can do that.

Enter the nano-scale world of microcircuitry.

Suddenly the "memristor effect" turns up, and it screws up things for people who don't know about it, or understand what they're seeing.

As the famous saying goes: It isn't when someone shouts "EUREKA!" that great scientific discoveries occur, it's when you mumble quietly to yourself, "That's odd..."

A memristor is a device that changes its resistance based on the direction in which current flows through it. In one direction, the resistance goes down. In the other, the resistance goes up. Turn off the current flow, the resistance stops changing - and stays right where it's at.

Memory.

From the article:

(IEEE Fellow and nonlinear-circuit-theory pioneer Leon) Chua calls the HP work a paradigm shift; he likens the addition of the memristor to the circuit design arsenal to adding a new element to the periodic table: for one thing, “now all the EE textbooks need to be changed,” he says.

Chua is the engineer who postulated the existence of the memristor. I think he's right.

And I think it will get him a Nobel Prize.

The memristor's memory has consequences: the reason computers have to be rebooted every time they are turned on is that their logic circuits are incapable of holding their bits after the power is shut off. But because a memristor can remember voltages, a memristor-driven computer would arguably never need a reboot. "You could leave all your Word files and spreadsheets open, turn off your computer, and go get a cup of coffee or go on vacation for two weeks," says Williams. "When you come back, you turn on your computer and everything is instantly on the screen exactly the way you left it."

The ultimate in non-volatile RAM.

But here's the part that really got my attention:

(HP senior fellow Stanley) Williams is in talks with several neuroscience/engineering labs that are pursuing the goal of building devices that emulate neural systems. Chua says that synapses, the connections between neurons, have some memristive behavior. Therefore, a memristor would be the ideal electronic device to emulate a synapse.

By redesigning certain types of circuits to include memristors, Williams expects to obtain the same function with fewer components, making the circuit itself less expensive and significantly decreasing its power consumption. In fact, he hopes to combine memristors with traditional circuit-design elements to produce a device that does computation in a non-Boolean fashion. "We won't claim that we're going to build a brain, but we want something that will compute like a brain," Williams says. They think they can abstract "the whole synapse idea" to do essentially analog computation in an efficient manner. "Some things that would take a digital computer forever to do, an analog computer would just breeze through," he says.

The HP group is also looking at developing a memristor-based nonvolatile memory. "A memory based on memristors could be 1000 times faster than magnetic disks and use much less power," Williams says, sounding like a kid in a candy store.

See? Skynet!

Now, think about that in conjunction with this piece Instapundit pointed to earlier today: Where Are They? Why I hope the search for extraterrestrial life finds nothing.

In that piece, author Nick Bostrom postulates that the reason SETI and its ancestors have never found evidence of another intelligent species in the universe is because there aren't any - and that's a good thing - because if there were, they would have already overrun us in their expansion. That we haven't seen anyone is indicative of the rarity of intelligent life due to what he calls the "Great Filter":

We have every reason to believe that the observable universe contains vast numbers of solar systems, including many with planets that are Earth-like, at least in the sense of having masses and temperatures similar to those of our own orb. We also know that many of these solar systems are older than ours.

From these two facts it follows that the evolutionary path to life-forms capable of space colonization leads through a "Great Filter," which can be thought of as a probability barrier. (I borrow this term from Robin Hanson, an economist at George Mason University.) The filter consists of one or more evolutionary transitions or steps that must be traversed at great odds in order for an Earth-like planet to produce a civilization capable of exploring distant solar systems. You start with billions and billions of potential germination points for life, and you end up with a sum total of zero extraterrestrial civilizations that we can observe. The Great Filter must therefore be sufficiently powerful--which is to say, passing the critical points must be sufficiently improbable--that even with many billions of rolls of the dice, one ends up with nothing: no aliens, no spacecraft, no signals. At least, none that we can detect in our neck of the woods.

Now, just where might this Great Filter be located? There are two possibilities: It might be behind us, somewhere in our distant past. Or it might be ahead of us, somewhere in the decades, centuries, or millennia to come.

He's betting on "in our past," because, he says:

If the Great Filter is indeed behind us, meaning that the rise of intelligent life on any one planet is extremely improbable, then it follows that we are most likely the only technologically advanced civilization in our galaxy, or even in the entire observable universe. (The observable universe contains approximately 10²² stars. The universe might well extend infinitely far beyond the part that is observable by us, and it may contain infinitely many stars. If so, then it is virtually certain that an infinite number of intelligent extraterrestrial species exist, no matter how improbable their evolution on any given planet. However, cosmological theory implies that because the universe is expanding, any living creatures outside the observable universe are and will forever remain causally disconnected from us: they can never visit us, communicate with us, or be seen by us or our descendants.)

The other possibility is that the Great Filter is still ahead of us. This would mean that some great improbability prevents almost all civilizations at our current stage of technological development from progressing to the point where they engage in large-scale space colonization. For example, it might be that any sufficiently advanced civilization discovers some tech­nology--perhaps some very powerful weapons tech­nology--that causes its extinction.

This was the fascinating idea behind a not very well written science-fiction novel from the late 1980's, The Toolmaker Koan. A koan is a buddhist thought-puzzle. In this case the puzzle is "why do all intelligent species rise to the level of toolmaker, then make tools that wipe themselves out?"

I thought the juxtaposition of these two pieces today was quite interesting. Perhaps we have just discovered the seeds for real "artificial intelligence" that can pass the Turing Test.

And possibly the seeds of our own "Great Filter"?