RichardKennaway comments on AI timeline predictions: are we getting better? - Less Wrong

54 Post author: Stuart_Armstrong 17 August 2012 07:07AM

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Comment author: shminux 22 August 2012 03:31:51PM 0 points [-]

Zeroth approximation: even the experts don't know, I am not an expert, so I know even less, thus I should not make any of my decisions based on singularity-related arguments.

First approximation: find a reference class of predictions that were supposed to come true within 50 years or so, unchanged for decades, and see when (some of them) are resolved. This does not require an AI expert, but rather a historian of sorts. I am not one, and the only obvious predictions in this class are the Rapture/2nd coming and other religious end-of-the-world scares. Another standard example is the proverbial flying car. I'm sure there ought to be more examples, some of them are technological predictions that actually came true. Maybe someone here can suggest a few. Until then, I'm stuck with the zeroth approximation.

Comment author: Dolores1984 22 August 2012 05:16:00PM 2 points [-]

Flying cars may be a bad example. They've been possible for some time, but as it turns out, nobody wants a street-legal airplane bad enough to pay for it.

Comment author: shminux 22 August 2012 06:07:32PM 1 point [-]

What people usually mean when they talk about flying cars is something as small, safe, convenient and cheap as a ground car.

Comment author: RichardKennaway 23 August 2012 10:33:43AM *  5 points [-]

What people usually mean when they talk about flying cars is something as small, safe, convenient and cheap as a ground car.

There will never be any such thing. The basic problem with the skycar idea -- the "Model T" airplane for the masses -- is that skycars have inherent and substantial safety hazards compared to ground transport. If a groundcar goes wrong, you only have its kinetic energy to worry about, and it has brakes to deal with that. It can still kill people, and it does, tens of thousands every year, but there are far more minor accidents that do lesser damage, and an unmeasurable number of incidents where someone has avoided trouble by safely bringing the car to a stop.

For a skycar in flight, there is no such thing as a fender-bender. It not only travels faster (it has to, for lift, or the fuel consumption for hovering goes through the roof, and there goes the cheapness), but has in addition the gravitational energy to get rid of when it goes wrong. From just 400 feet up, it will crash at at least 100mph.

When it crashes, it could crash on anything. Nobody is safe from skycars. When a groundcar crashes, the danger zone is confined to the immediate vicinity of the road.

Controlling an aircraft is also far more difficult than controlling a car, taking far more training, partly because the task is inherently more complicated, and partly because the risks of a mistake are so much greater.

Optimistically, I can't see the Moller skycars or anything like them ever being more than a niche within general aviation.

Comment author: shminux 23 August 2012 03:34:29PM 4 points [-]

It not only travels faster (it has to, for lift, or the fuel consumption for hovering goes through the roof, and there goes the cheapness), but has in addition the gravitational energy to get rid of when it goes wrong. From just 400 feet up, it will crash at at least 100mph.

Failure of imagination, based on postulating the currently existing means of propulsion (rocket or jet engines). Here are some zero energy (but progressively harder) alternatives: buoyant force, magnetic hovering, gravitational repulsion. Or consult your favorite hard sci-fi. Though I agree, finding an alternative to jet/prop/rocket propulsion is the main issue.

When it crashes, it could crash on anything. Nobody is safe from skycars.

If it doesn't have to fall when there is an engine malfunction, it does not have to crash.

Controlling an aircraft is also far more difficult than controlling a car, taking far more training, partly because the task is inherently more complicated, and partly because the risks of a mistake are so much greater.

This is actually an easy problem. Most current planes use fly-by-wire, and newer fighter planes are computer-assisted already, since they are otherwise unstable. Even now it is possible to limit the user input to "car, get me there". Learning to fly planes or drive cars will soon enough be limited to niche occupations, like racing horses.

Incidentally, computer control will also take care of the pilot/driver errors, making fender-benders and mid-air collisions a thing of the past.

Optimistically, I can't see the Moller skycars or anything like them ever being more than a niche within general aviation.

Absolutely, this is a dead end.

Comment author: RichardKennaway 23 August 2012 04:42:10PM *  0 points [-]

Failure of imagination, based on postulating the currently existing means of propulsion (rocket or jet engines). Here are some zero energy (but progressively harder) alternatives: buoyant force, magnetic hovering, gravitational repulsion. Or consult your favorite hard sci-fi.

I also can dream.

Comment author: Michael_Sullivan 23 August 2012 01:26:25PM *  3 points [-]

You say that "There will never be any such thing", but your reasons tell only why the problem is hard and much harder than one might think at first, not why it is impossible. Surely the kind of tech needed for self-driving cars, perhaps an order of magnitude more complicated, would make it possible to have safe, convenient, cheap flying cars or their functional equivalent.

At worst, the reasons you state would make it AI-complete, and even that seems unreasonably pessimistic.

Comment author: RichardKennaway 23 August 2012 05:45:08PM *  1 point [-]

I'll cop to "never" being an exaggeration.

The safety issue is a showstopper right now, and will be until computer control reaches the point where cars and aircraft are routinely driven by computer, and air traffic control is also done by computer. Not before mid-century for this.

Then you have the problem of millions -- hundreds of millions? -- of vehicles in the air travelling on independent journeys. That's a problem that completely dwarfs present-day air traffic control. More computers needed.

They are also going to be using phenomenal amounts of fuel. Leaving aside sci-fi dreams of convenient new physics, those Moller craft have to be putting at least 100kW into just hovering. (Back of envelope calculation based on 1 ton weight and 25 m/s downdraft velocity, and ignoring gasoline-to-whirling-fan losses.) Where's that coming from? Cold fusion?

"Never" turns into "not this century", by my estimate.

Of course, if civilisation falls instead, "never" really does mean never, at least, never by humans.

Comment author: shminux 23 August 2012 06:54:51PM 1 point [-]

Leaving aside sci-fi dreams of convenient new physics

Or new technology relying on existing physics? Then yes, conventional jets and turbines are not going to cut it.

Comment author: wedrifid 25 August 2012 05:04:14PM 1 point [-]

There will never be any such thing. The basic problem with the skycar idea -- the "Model T" airplane for the masses -- is that skycars have inherent and substantial safety hazards compared to ground transport.

Your certainty seems bizarre. There seems to assumption that the basic problem ("being up in the air is kinda dangerous") is unsolvable as a technical problem. The engineering capability and experience behind the "Model T" was far inferior to the engineering capability and investment we are capable of now and in the near future. Moreover, one of the greatest risks involved with the Model T was that it was driven by humans. Flying cars need not be limited to human control.

There is no particularly good reason to assume that flying cars couldn't be made as safe as the cars we drive on the ground today. Whether it happens is a question of economics, engineering and legislative pressure.