Oversights

In some cases the principles at stake were discovered decades or centuries before, but the technological environment wasn't yet rich enough to enable development.

Steam powered toys could be made to work with Ancient Greek technology, but building a serious steam engine requires the ability to shape metal parts such as pistons and cylinders in a larger size, harder metal, and with more precision than was practical in Hero's time.

When an inventor approached the famous company of Boulton and Watt in the early 19th century with an idea for a steam turbine, Boulton asked Watt if it could be done. Watt did some calculations and answered something like, "Unless God so make it that a machine can turn 3,000 times per minute, it's not going to be as efficient as our engines." The principles were well understood but the materials and tolerances were not achievable at the time.

Alan

I invented the electronic book in 1977 at GEC Hirst Research Centre.

Dirk

Not Egypt. You are thinking of the famous Baghdad battery.

There are suggestions of Egyptian use of electricity, however. One such hint is that the paintings and carvings deep INSIDE the tombs were all done without the use of flames for lights because there are no traces of soot or smoke down there. Even MORE interesting are the carvings at the temple of Hathor at Dendera. These seem to represent objects very similar to Crookes tubes. Of course, such theories are always rejected out of hand as "bad archeology" because they were not put forward by the archeology establishment. Hence the accepted rule is that the laws of physics did not exist in ancient times making such inventions "impossible".

I've pointed out here many times that proving something is "impossible" is the mathematical equivalent of saying "I'm a moron". There are innumerable examples. You can prove something is possible by simply building one and doing it. But to prove it's "impossible" means you must possess God-like knowledge of all things past, present and future. Hence the rule.

Nonsense. A proof is a proof, meaning that what it says is true. It's quite possible to be mistaken about it, but that's a blunder, not a logical principle.

I invite you to build a communications link that violates Shannon's theorem, and then come back and tell me that he was a moron.

Cheers

Phil Hobbs

Alan Meyer wrote:

Conceded. It seems to me, however, that it could have been done centuries earlier than it was. Certainly, military-related developments would be the template. I was expecting some of James Burke's "Connections" to propagate more rapidly. I'm not finding useful dates between extremes.

A battery could have been built 2000 years ago, and electric currents, ohmic heating, electromagnetism, all that discovered.

John

But isn't the above just an attempt at proving it's impossible to prove something is "impossible"?

-- Joe

There are a couple of papers from the Proceedings IEEE back around 1980 that purported to show that for theoretical reasons IC features could not be reduced below 100nm. We are now on 22nm and moving towards 12nm...

I think you need tp precede steam tech with gunpowder and cannons

Dirk

But what about insulated wire?

Copper + fabric + tar. Electroplating could be useful.

Best regards, Spehro Pefhany

Sure, people get things wrong. I'm often wrong myself, and perhaps you've made one or two mistakes in your career too. But there are things, even in technology, that are intrinsically impossible. I gave breaking the Shannon limit as an example, Some other examples would be:

(1) over unity power efficiency; (2) Running solid state anything at above 5000 kelvin; (3) Determining whether the light brown liquid sold by the roach coach contains any actual coffee whatever. ;)

Cheers

Phil Hobbs

It depends on what other factors are being omitted. For example, radioactive decay energy could like just like overunity if you had no idea of the mechanism

Are you sure no material will ever be constructed that cannot function above 5000K? Is it theoretically impossible to use the inner electrons of some element(s) to provide the chemical binding, rather than outer ones?

As for the Shannon Limit, maybe there are some quantum tricks that might circumvent it. How sure are you?

Dirk

I saw somewhere that one of the supposed uses of the Baghdad batter might have been electroplating

Dirk

I'm not talking about ignorance or blunders. So that's out of court.

I'm sure that no solid material will ever function over 5000K, because there are no chemical bonds that are strong enough to keep a solid together at that temperature.

You can't get the nuclei close enough for the inner shell levels to split significantly, and even if you could, that would put the nuclei too close together for the electrostatic shielding of the outer shell electrons to operate, resulting in keV-MeV level energy barriers. That repulsion is what makes fission events energetic.

If you want to pin me down, I'd add that it would need to be near atmospheric pressure. I very much doubt that anyone will ever do any engineering on a white dwarf star, where electron-degenerate matter seems to act rather like a solid, but that might not be impossible in the same way. (White dwarfs have starquakes, which suggests that they're at least partly solid.)

The assumption of the Shannon theorem is a single noisy but otherwise deterministic communication channel. If you're postulating quantum superposition, that violates the premises of the theorem. Somebody with a private definition of signal to noise ratio (e.g. delta-sigma ADC makers) might claim to do better, but that violates the premises as well.

I'm in full agreement that there are lots of folks who toss around the word "impossible" in an indefensibly loose fashion, but IMO one big reason it's indefensible is that it obscures the fact that there are lots of truly impossible things.

Cheers

Phil Hobbs

True, but you need to define your assumptions quite precisely in order to make any case watertight

Dirk

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Quantum physics can be used to back up the most insane, illogical BS imagineable.

To use quantum physics as an out in a logical discussion should be seen as a forfeit, and you forfeit any credibility you might have had.

That being said, the few nagging quantum breakthroughs that might possibly enable instantaneous connection and communication at great distances would upset most logical thought and probably be treated as a black box function by old school engineers.

If you don't accept that some things are impossible, then for a given problem, the solution space expands, literally, by an infinite amount. That could make it hard to finish a design.

Most designers know that many things are impossible, so don't waste their time trying. It's the borderline cases that are interesting, and profitable, the ones that are possible but most other people think are impossible.

John