Could a Holistic Detective Agency Actually Exist?

[Wowbagger]

I consider Dirk Gently's Holistic Detective Agency, by Douglas Adams, to be one of the greatest novels of intrigue ever written. But, this thread should NOT be about the novel. I would like to discuss the scientific merit of such an enterprise, using general concepts from the book as a basis.

Based on everything we know about physics, could such a detective agency actually exist? Could we, in principal, use the "interconnectedness of all things" to solve crimes?

Or, as Dirk, in Chapter 10 of The Long Dark Tea-Time of the Soul, suggested:

If I could interrogate this table leg in a way that made sense to me, or to the table leg, then it would provide me with the answer to any question about the universe.

(No, we are not going to discuss if Dirk, himself, provided a legitimately holistic detective agency, or was just ripping off old ladies. The status of Dirk's thing is irrelevant to the question of such a thing actually being possible, or not. Again, this is about the science, not the fiction.)

(Oh, and for the record: This has nothing to do with "holistic healing", or anything like that. We are more concerned with resolving murders, messy divorces, lost pets, and stuff like that.)

Sometimes, quantum physics is cited as a justification for this type of idea. But, isn't there a lot of uncertainty in quantum physics? Wouldn't the presence of such uncertainty debunk the very idea of holistic detectives? The "signal" would get more and more "noisy" with uncertainties, the more degrees of separation you are from the target of your query.

And, are all things in the Universe even so interconnected, to begin with? It seems vast distances, at least, should keep a certain level of independence in the actions that take place on different planets. Even if there is still a force of gravity between them all. If we ignore quantum uncertainty, could we still be able to interrogate a table leg, on Earth, to learn about a volcano on Venus, for example?

Are there any other forces, known to physics, that would allow different material objects to not effect other material objects, thus breaking any "interconnectivity" the detective would be trying to rely on?

Because, if this whole idea actually works, I may have a new business plan to write up.

 

[Wowbagger]

I happend to notice that a thread on a somewhat-similar topic was started in April, by someone else: http://www.internationalskeptics.com/forums/showthread.php?t=139506

But, its responses were quite unhelpful. I suspect my opening post, here, makes the discussion a bit easier to grasp.

 

[sol invictus]

If we ignore quantum uncertainty, could we still be able to interrogate a table leg, on Earth, to learn about a volcano on Venus, for example?

Yes, I suppose.

But you're correct that quantum mechanics probably means we cannot. One way to understand that is to compute the entropy of the table leg, which will be of order the number of atoms making it up (10^23 or so). That entropy is the maximum number of bits of information the table leg can possibly contain. But the universe as a whole contains a vastly greater amount of information; therefore the table leg doesn't know much about the universe.

 

[Wowbagger]

One way to understand that is to compute the entropy of the table leg, which will be of order the number of atoms making it up (10^23 or so). That entropy is the maximum number of bits of information the table leg can possibly contain.

Since there are multiple properties of an atom, I would think each atom could contain more than one bit of information.

What about the "way the atoms move around"? That could be even more bits.

The following is almost a different question, but I think it is relevant enough to the discussion:

What if we deduced a "fundamental pattern" to all material in the Universe? We could extrapolate, from that pattern, any information about anything, anywhere. .... uh... right?

If you're familiar with The Total Perspective Vortex, I suspect it would stand or fail for any of the same reasons as a holistic detective. And, I think the Vortex was supposed to work on the "pattern" principal I just asked about.

 

[Soapy Sam]

You've been snorting cement again, haven't you?

 

[Myriad]

It depends on the type of pattern. For a pattern like the Mandelbrot Set, knowing the underlying system that creates the pattern means that you can generate whatever portion of the pattern you want, in a relatively few steps. But for a pattern like Wolfram's Rule 110 cellular automaton, knowing the underlying rule is no help at all in determining what the pattern will look like at any particular place and time; the only option is to evolve the whole pattern from the beginning (or some known starting point, at least) and examine the results (i.e. re-create the universe, or observe the existing one).

Respectfully,
Myriad

 

[sol invictus]

Since there are multiple properties of an atom, I would think each atom could contain more than one bit of information.

Yes, that's true in principle - but the same goes for all the other atoms in the universe, so you can't win that way.

What about the "way the atoms move around"? That could be even more bits.

No, not really - that's already taken into account by the entropy (recall that it's the exponential of the entropy that's the information capacity). And anyway, the same objection as above applies.

 

[Wowbagger]

the only option is to evolve the whole pattern from the beginning (or some known starting point, at least) and examine the results (i.e. re-create the universe, or observe the existing one).

If we study the Cosmic Microwave Background Radiation sufficiently well, would that allow us to extrapolate everything else about the Universe?

Yes, that's true in principle - but the same goes for all the other atoms in the universe, so you can't win that way.

Here's a more basic question: What if most of the information was redundant, anyway? What if a table leg, if interrogated properly, can act like the ultimate compression algorithm?

 

[I Ratant]

Is that any different than the drunk looking for his lost car keys under the street light where the light is better, rather than where he lost them?
Knowing everything possible about a table leg tells you what about the internal combustion motor?

 

[Ziggurat]

If we study the Cosmic Microwave Background Radiation sufficiently well, would that allow us to extrapolate everything else about the Universe?

Nope. Even in principle, we can only ever access a small fraction of it, which isn't enough.

Here's a more basic question: What if most of the information was redundant, anyway? What if a table leg, if interrogated properly, can act like the ultimate compression algorithm?

Thermodynamics doesn't prohibit such a thing, but that's not enough. You need some mechanism which actually does such an encoding, and you need to understand that mechanism in sufficient detail to decode it. There's no reason to think that any such mechanism exists (why would it only throw out the useless information and retain all the important information?), and even if it did, the encoding couldn't be the same for different objects, and how do you find out how to decode from what is, in effect, a unique object? The enterprise is unlikely.

 

[sol invictus]

Thermodynamics doesn't prohibit such a thing, but that's not enough.

Actually I think it does.

Suppose the table leg contained all the information about the rest of the universe in some highly compressed form. That means it has an entropy larger than the entropy of the entire rest of the universe (that's a precise statement - information is literally entropy).

Great - now take that table leg and burn it. By the second law of thermodynamics, that process must increase the total entropy, and by unitarity none of the information in the table leg can have been lost. But now we have a very similar universe to the one we started, except with no table leg and little extra ash and radiation which quickly gets mixed up and absorbed... but somehow with much more entropy than it had before, even though there's only been a tiny heat exchange. But that violates the laws of thermodynamics - entropy can't just vastly increase like that when nothing much has happened, at least not in any physically sensible system.

That's not as sharp a contradiction as it could be, but I think we could probably make it so - for example if we're allowed to make another such table leg, we could burn that, and ad infinitum doubling the entropy at every stage. But if we're not allowed to make another such table leg, then there must have been something very special about the universe we started with which allowed it to exist.

 

[Mister Agenda]

Any chance this is similar to what the math professor in NUMB3RS does?

 

[Ziggurat]

Actually I think it does.

Suppose the table leg contained all the information about the rest of the universe in some highly compressed form. That means it has an entropy larger than the entropy of the entire rest of the universe

I don't think that's what was being suggested. I read that hypothetical as proposing that the table leg contained the important information - ie, a VERY lossy compression, where you're throwing out lots and lots of information you don't need. So the entropy requirements for the table leg could be modest, because lossy compression does reduce entropy. But while not thermodynamically prohibited, such a scenario makes little physical sense.

 

[sol invictus]

I don't think that's what was being suggested. I read that hypothetical as proposing that the table leg contained the important information - ie, a VERY lossy compression, where you're throwing out lots and lots of information you don't need.

Well, sure - in that case I agree. I suspect that all the information important to the human race currently could be stored in a table leg (10^23 bits is a lot).

But this: "Here's a more basic question: What if most of the information was redundant, anyway? What if a table leg, if interrogated properly, can act like the ultimate compression algorithm?" sounds to me like it's asking about a near-perfect compression algorithm that can compress all the information in the universe down to a table leg. I think that is impossible, for the reasons I gave above.

 

[Ziggurat]

But this: "Here's a more basic question: What if most of the information was redundant, anyway? What if a table leg, if interrogated properly, can act like the ultimate compression algorithm?" sounds to me like it's asking about a near-perfect compression algorithm that can compress all the information in the universe down to a table leg. I think that is impossible, for the reasons I gave above.

Well, for that, you don't even have to make fancy scenarios to answer in the negative: Lossless compression doesn't (and can't) change entropy, and a table leg obviously has less entropy than the rest of the universe.

 

[sol invictus]

Well, for that, you don't even have to make fancy scenarios to answer in the negative: Lossless compression doesn't (and can't) change entropy, and a table leg obviously has less entropy than the rest of the universe.

Well, that's the question I was addressing - is it consistent with the laws of thermodynamics and statistical mechanics for a table leg to have as much entropy as the rest of the universe.

It's not quite as easy as you make it sound. For example, the entire rest of the universe could in principle be in a pure state, with strictly zero entropy.

 

[Ziggurat]

Well, that's the question I was addressing - is it consistent with the laws of thermodynamics and statistical mechanics for a table leg to have as much entropy as the rest of the universe.

It's not quite as easy as you make it sound. For example, the entire rest of the universe could in principle be in a pure state, with strictly zero entropy.

As a practical matter, it's very easy. Measure the heat capacity vs. temperature of the table leg, and you'll end up with its entropy. Measure the heat capacity of something else, and you'll end up with its entropy. Do that for enough other stuff, you'll have more entropy in the other stuff than in the table leg.

Furthermore, since entropy is in large part about information, if we have no information about the microscopic state of the universe and no way of attaining it (both of which surely apply), then I think its entropy IS large, regardless of whether or not some god prepared it in a pure state.

 

[sol invictus]

As a practical matter, it's very easy. Measure the heat capacity vs. temperature of the table leg, and you'll end up with its entropy. Measure the heat capacity of something else, and you'll end up with its entropy. Do that for enough other stuff, you'll have more entropy in the other stuff than in the table leg.

Yes, but that's using a coarse definition of entropy, and it doesn't exclude some in-principle loopholes.

Furthermore, since entropy is in large part about information, if we have no information about the microscopic state of the universe and no way of attaining it (both of which surely apply), then I think its entropy IS large, regardless of whether or not some god prepared it in a pure state.

But that's assuming the answer. The question was whether it's possible in principle, not whether we can do it given what we know now.

Actually another constraint occurred to me - if the entropy of the universe is anything remotely close to what you'd expect, the table leg would have more entropy than a black hole of the same size (because it has more entropy than the universe, which contains many large black holes plus lots of other stuff). But that raises all sorts of intractable problems - like what happens if you throw the table leg into a small black hole. You should get a slightly larger black hole with the usual entropy, but that would violate the 2nd law, since dropping the leg in is an irreversible process.

So with that in mind, the most information our table leg can possibly store is around 10^70 bits, because that's the entropy of a meter-sized black hole. But the entropy of the universe should be around 10^90.

 

[Ziggurat]

Yes, but that's using a coarse definition of entropy, and it doesn't exclude some in-principle loopholes.

The only loophole I can think of is some absurdly large degeneracy in the ground state of the table leg. Unless your table leg is made out of exotic matter, I think that one can be discounted.

 

[Wowbagger]

The spirit of the challenge involves answering "any question about the Universe". So, the table leg would have to, somehow, contain lossless compression of all the information in the Universe.

I suspect such a thing could only occur if the vast majority of information is redundant, and can actually be narrowed down to one or two "fundamental patterns", of some sort.

As was pointed out: We can only see a tiny portion of the CMB. But, if we could, hypothetically, see all (or almost all) of it, I suppose that could change things. We could discover what those "fundamental patterns" are, and we could then extrapolate them from everything else, including table legs.

Maybe.

(I apologize if this is starting to sound a little looney, but it is only meant to be a thought exercise.)