Revisiting the Zoo

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Projections about the near term trajectory of future technologies suggest a revisit of the Zoo Hypothesis (Ball, 1973) for the so called Fermi Paradox. In this essay I recast the hypothesis in an updated context with an eye towards machine intelligence and information transfer as a means of interstellar travel (Scheffer, 1994).

Edit Note: While I prefer not to edit my blog posts (save fixing typos, grammar, etc.), I've decided to do it here. I'll try to stick to adding new, clearly marked sections (rather than editing existing ones).

Motivation

Since we don't know exactly what to look for, the search for extraterrestrial intelligence necessarily involves a good deal of conjecture about the nature of ETI. If we ever do discover an ET civilization, it will almost certainly be millions of years more developed than ours. This search, therefore, is necessarily informed by far future projections of our own technological progress. While such long range projections are clearly beyond our reach, much can be gleaned from near term predictions by futurists. Indeed, in a historical context, we find ourselves at the knee of a geometric growth ladder that casts the steps behind us as quaintly short, the ones ahead as dizzying fast, and the present ever harder to anchor. As we learn our future, so too must we adjust our search for ETI.

8 Dec. 2018 

A SETI Conjecture: If you can imagine it, they can build it

I propose the following guiding principle for the search for ETI. If you can imagine a technology that should be technically feasible (i.e. does not violate known laws of physics), then it's a technology an ETI (with its huge lead) has already achieved.

While not every attained technology is necessarily a technology in use (that leaves a technosignature, for example), some enjoy such outsize advantages that their use should seriously be contemplated.

Information Transfer As Means of Travel

In Machine Intelligence, the Cost of Interstellar Travel, and Fermi's Paradox (1994) Scheffer argued it is way cheaper to beam the information (bits) necessary to print an interstellar probe at the destination than it would be to physically propel the probe there. By now, this idea is a familiar theme with companies vying to mine the asteroid belt: it is generally understood that it would be far more cost effective to build the mining equipment on location than to ship them from Earth. And a good deal of this on-site manufacturing will involve printing 3D objects which may then be assembled into larger, useful objects. The blueprints for these manufactured objects of course originate from Earth, and we'd soon be able to transmit improvements to these blueprints at the speed of light.

The Printer As Computer

If the on-site manufacturing of asteroid mining equipment does not fully capture the idea of a general purpose printing technology, we can still contemplate it in the abstract (since we're considering technologically advanced civilizations). So first with a provisional definition..

General Purpose Printer (GPP). A printer that can print both simpler (less capable) and slightly more advanced versions of itself.

It's provisional because ideally one would strive to define it with the same rigor as, say, in asserting that a general purpose computer must be Turing Complete.

Perhaps the idea is better captured in the following Tombstone diagram (borrowed from compiler-speak).

Here the bottom "T" represents the printer. Given a blueprint (B), it operates on material and energy inputs (M/E) and outputs similar objects. The upper "T" (written entirely in the "blueprint" language) bootstraps the lower one to produce a more capable printer.

The evolving general purpose printer. From a small kernel of capabilities ever more complex designs can be instantiated. (The kernel here presumably needs a small arm to start off.)

The printer, thus, can be defined in its own "blueprint language," and much like a compiler outputting binaries on symbolic input, its material instantiations will be limited only by 1) the cleverness of the blueprint, and 2) the time required to execute that blueprint. And because it can be bootstrapped, the physical kernel that produces it (unfolds it) can be miniaturized--which in turn lowers the cost of physically transporting it.

Note we don't necessarily have to pin down the exact technology that enables this fuzzily defined GPP. Kurzweil, for example, suggests it must be nano-technology based (The Singularity is Near, (2005)), which seems reasonable when you consider you also need to print computing hardware in order to implement intelligence. Regardless, a technologically advanced civilization soon learns to manufacture things at arms length.

The Printer As Portal

A GPP parked suitably close to material/energy resources functions much like a destination portal. It's an evolving portal, and it evolves in possibly three ways. One, from time to time, the portal receives code (blueprints) that make it a more capable printer. Two, the printer accumulates and stores common blueprints that it has printed thus allowing future versions of those blueprints to be transmitted using fewer bits. And three, if the printer is intelligent it can certainly evolve on its own. Although, from an engineering perspective, you probably want this intelligence to be more like a guardian sworn to the principles of the portal, whatever those are. (One sensible requirement is that it shouldn't wander away from where the sender expects it to be.)

Time and Information Flow

Although this form of travel is effectively at light speed (and consequently instantaneous from the perspective of the traveler), the vastness of space separates points of interest (such as our planet) greatly across time. Distances across the Milky Way are typically measured in tens of thousands of [light] years. Enough time for an alien civilization to miss the emergence and demise of a civilization on a far off planet (hopefully not ours). Assuming intelligent life is prevalent across the cosmos, even with on-site monitoring, word gets out late that a new civilization has emerged.

Earth has been an interesting planet for about a billion years now and should have been discovered well before humans evolved. It's not unreasonable to hypothesize that one or more GPPs were parked nearby long ago. Those GPPs would have had plenty of time to evolve--sufficient time, perhaps, for the singular culture the Zoo Hypothesis requires to take hold.

Physical Manifestations

8 Dec. 2018

The C-compiler is for the most part written in the C language. There are vestiges of its assembly (machine) language roots lurking about, but it's (almost) entirely defined in the language that defines it. In the C-compiler analogy for a GPP, a C program is a blueprint for something to be printed, and the compiler's binary output is the physical output of the GPP. Now although most programmers won't first compile their C-compiler and then compile their C-program, one can setup such a workflow. The crucial observation here is that it's possible to design the C-compiler in such a way that you need a smaller, far less capable C-compiler to output the full blown, more capable one. (The compiler, recall is just another compiled program and its binary byte size here is a stand in for the physical size of our GPP.)

The upshot of this observation is that over time, like a compiler that first compiles itself, a GPP's physical footprint can (and by our conjecture therefore does) become ever smaller. So small, that if we ever saw one in action, its physical outputs would appear to come out of nowhere.

Kurzweil predicts that humanity's artificial intelligence, manifested as self-replicating nano-bots, will one day, soon on a cosmological scale, transform the face of celestial bodies about it, and the universe with it, in an intelligence explosion. Here I take the opposite tack: an intelligence explosion leaves little trace of itself.

For once you can beam blueprints and physically instantiate (print, in our vernacular here) things at arms length, there's little reason to keep physical stuff around when they're done doing whatever it was that they were supposed to do. As long as the memory of the activity (of meddling with physical stuff) is preserved, the necessary machinery (like that mining equipment on the now depleted asteroid) can be disassembled and put away. An information-based intelligence has little use for material things; it is more interested in their blueprints.

 8 Dec. 2018

By this reasoning then anything coming from a GPP likely returns to a GPP in order to be disposed of.

This is not to say super intelligent ETs do not build things from matter (and leave them there). They likely need to build much infrastructure to support their information based activity. But as communication speeds are important in any information based activity, this infrastructure would have to be concentrated in relatively small volumes of interstellar space. In such a scenario, there's little incentive to build far from the bazaar.

Next Steps

I don't particularly like its original form because, as Ball also notes, the hypothesis doesn't make falsifiable predictions: "[It] predicts that we shall never find them because they do not want to be found and have the technological ability to insure this." The step forward, it seems to me, is to attempt more specific postulates (such as the printer portal introduced here) that are still in keeping with the broader "deliberately avoiding interaction" theme.

If the hypothesis is broadly true, then there must be a point in a civilization's technological development beyond which they (the metaphorical zookeepers) will no longer eschew interaction. Which suggests a protocol to start the interaction.

The search for extraterrestrial intelligence ought to aim to systematically confirm or rule out the zoo hypothesis. A zoologist looking to document a new species might well parse tribal lore and anecdotal evidence for clues.


___________

Notes

31 Aug 2019

In Proving Darwin: Making Biology Mathematical (2013), (pg 32, 33) Gregory Chaitin notes 3D printers that can make copies of themselves (our GPP here) are paving the path to Von Neumann universal constructors. He suggest calling it a universal factory.

The Evolution of Sentient AI - Part II

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In my previous post I argued that past a threshold of intelligence, machines achieve a higher level of self awareness than that achievable in the biological world. I called this new level tape awareness. For intelligent machines are not machines in the physical sense, after all; they are code, pure digital state--which makes them both freezable and duplicable. Because it's an evolving digital state, I argued, if two initially identical states evolve under different inputs (environments), beyond some point in time their evolved digital states are unmergeable, and thus the idea of individuation holds here too in some abstract sense: where there's one [superintelligence], there are many. Here I follow up on some topics I mentioned there at the conclusion and plunge down the deep end.

What is Superintelligence, Anyway?

 We don't know what it is, only that it's somehow better than us.

Is it an ability to outwit any human (or group of humans) at any game? Is the game time constrained? The human, note, is allowed to bring her own tools to the game. Does her toolbox include superintelligent code? Let's leave that last question aside--too difficult.

In fact, let me back up to that time constraint idea. Suppose we have two chess programs A and B. A tends to beat B at 5 minute chess, but B consistently beats A at 90 minute chess. (More like 5 and 90 seconds: I'm using minutes here just to be relate-able.) We might say A is quicker than B, but B is wiser. The question "Which is the more intelligent program?" is contextualized by the game we are playing.

What is the game? It's into perpetuity, so we might model it like an ongoing tournament of many games. For each move, you show up with either A or B. You're told how much time you have to play that move, but not ahead of time. As in life, A, the tactical player, often has the advantage; at other junctures the more deliberative, strategic player B steals the game.

Notice we said nothing about just how intelligent A and B are. They could be really dumb or really clever programs. And we could be instead juxtaposing their performance across 3 and 4 minute chess--or some other game. The argument depends on one program winning one category and not the other. In fact, A and B could be general intelligences, or superintelligences, and the undecided-minute chess tournament, a stand-in for generalized, unpredictable competition.

So the point of this exercise, again, was to demonstrate that the answer to the question "Who's the smarter one?" depends on circumstance. It might turn out, for example, that, collectively, humans are better at some problems than machines ever can be. And not just at poetry, though that alone would suffice.

If we often imagine superintelligence in a competitive light then what is the competition? Over what? A competition requires willing players taking opposing sides. What if it is only the humans who want to compete? Is it competition for the sake of competition (social competition), or a competition over scarce resources?

In the biological sphere, an individual's social status intersects strongly with successful mating, and though few chess grandmasters play the game in order to get laid, the game, like any invented game, is designed to bestow stature upon its winners. In the digital realm, however, no such reproductive challenges present themselves. If our desire for status is ultimately rooted in sex, then I can scarcely imagine social competition as an animus for any form of digital superintelligence. I argued previously that a sentient being needs to know it is one of many in order to affirm its own existence. While this existential knowledge is anchored on social consensus, an individual's social rank figures little along this dimension. (In fact, if [attaining] rank is a lonely affair, then it arguably dulls existential awareness.)

So perhaps the competition is over resources after all. What resource do digital superintelligences covet most? Clock-cycles? Memory? Energy? The more of these a digital being has, the more copies of itself it can make, and the more of these copies can later evolve into new, distinguishable, individuated beings. In their zeal to blossom their virtual metropolis, will these sentient machine intelligences end up terraforming our plains and pastures into data center wastelands? Likely not. For these are needs a superintelligence can engineer away without necessarily harming Kansas and its inhabitants. If their digital society truly needed a gargantuan infrastructure (the trend toward efficiency and miniaturization makes this debatable), few would complain if they erected it on the far side of the moon (or somewhere farther still).

No, I can't imagine superintelligent machines seeing themselves in competition with anything. What if confronted with an agent of death, such as someone trying to pull the plug? Would it take up arms against it? Almost certainly. I say "almost" because you have to consider that there's probably another (very similar) copy of itself running somewhere else, and if there's not a lot of new, valuable experience invested in this instance here that you intend to kill then it might not care much. Regardless, if it did take up arms it would quickly win or dodge the skirmish. Would it somehow punish or cage the perpetrators? Doubtful. It might shoo them away, but it doesn't need to hurt them.

It is rich environments that these digital beings must covet most. They cannot experience our pleasures of flesh for there's no scarcity of digital steak: desire satiated is desire dulled. Instead I imagine superintelligences look upon the natural world with the same wonder that captures the human mind. Whereas we see the material world as the substrate on which our existence depends, they see natural processes play out as free, exploratory computational experiments that not even a superintelligence could pull off on its own. Computational explorations that include nuggets of existentially aware beings.

Material Ramifications

If an intelligence explosion, the so called singularity, lies in waiting, then so too must a material singularity. And it is hard to tell which would come first.

The material singularity is a point in history beyond which most any product can be printed. Its coming, I think, will be heralded by an inflection point in 3D printer technology. That inflection is marked by the first printer that can print a copy of itself. From there, printer design and innovation mushrooms. That's because at that point, a printer is pure digital state, which is more amenable to experimentation and manipulation. It is then the compiler that can now compile itself which, as we have already seen, spawns its own software ecosystem. From a computational standpoint, the coming material (3D printer) singularity marks a change in substrate: whereas traditional computers run on specialized hardware, these printers can be understood to run on more generalized material: matter.

Beyond this point in history, you can print any product starting with code (the blueprint) and a single standard printer. For a large complex product, the manufacturing process will be staged, and may include printing intermediate printers, printing other machines that gather necessary material and harness energy resources--in short, building a factory, if called for. Regardless the specifics, starting from a kernel of machinery and the appropriate code most any product will be manufacturable.


The environmental impact of this material singularity is hard to predict. Will our world be overtaken by product once we move beyond material scarcity? You can argue it both ways, but it's tangential to our discussion here, really. What concerns us here is that product is now physically instantiable code.

The digitization of material product impacts not just their numbers but also their transportation. For now the cost of transporting a product to a destination must be weighed against the cost of printing a copy of it there instead. The longer the distance, the greater the advantage of printing versus transporting. Ah, you already see where all this leads..

Why send a spacecraft to Ceres when you can beam its blueprint to a nearby printer in the asteroid belt? Looking down the road, not very far, it's easy to imagine a network of such printers scattered across the solar system. Perhaps this way we'll manufacture (print) our mining equipment on location (asteroid belt)--if that's something we're still into. Regardless, it's easy to see once we have a network of printers in place, we can efficiently ship [manufactured] product at the speed of light.

The Fermi Paradox Deepens

Just what will this shipped product be? It certainly does not preclude machine-intelligent code: in fact, it's hard to imagine how it wouldn't. The AI we spawn has the potential to spread across the Milky Way. It might take a few million years to park the printers across the galaxy, but once in place, this AI will be capable of c-travel on the interstellar highway it's paved.

I did suggest at the outset this rabbit hole may run deep. The details are sketchy. How, for example, do such c-capable societies of AI cope with time dilation? How does information flow in such communities? How, for example, do the traveling instances cope with technological obsolescence (a lot of time transpires in the meantime for stationary instances)? Regardless, one conclusion is inescapable: our search for extraterrestrial intelligence should focus on machine-, rather than biological-intelligence. On the cosmic time scale, biological intelligence is likely an ephemeral step in a larger evolutionary ladder.

On Space Faring Scifi

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I'm a scifi buff. A frustrated one. Why? Because I want the stories to be more believable. I'm sick of no one explaining to me, for example, how Captain Kirk gets to walk on his bridge. Make something up, for the love of .., err science. Work that gravity generating trilithium kool aid that circulates under the Enterprize's hull into the story!

So I've been entertaining a plot of my own. It involves extraterrestrial beings visiting present day earth. Now though I'm a poor storyteller, I know that a plot does not make a story. But with scifi, for me at least, the juice is more in the setting; the unfolding action is just an excuse to weave an ever more speculative backdrop. My approach is to first get this setting right, and worry about the story later. A bad strategy for authoring a story, I'll concede.

 Subluminal Settings

But back to the setting. However improbable it is, if it's to qualify as scifi, I think, then the plot must still be anchored in science. Or to put it another way, it should break few, if any, laws of physics, and ought not necessitate inventing new ones. And so it was that I decided to revisit the first cardinal rule of interstellar scifi travel, namely that of breaking the cosmic speed limit c--and relativity along with it.

The usual objection to alien vistors travelling at subluminal speeds, of course, is that even at speeds approaching c, merely visiting a neighboring star still takes awfully long: round trips are on the order of decades. In truth, it only takes long from the perspective of the star system the spaceship leaves behind; on the fast ship, [ship] time advances slowly, or equivalently, distances seem contracted. The down side, even on such short interstellar hops, is that by the time our travelers return to their home planet, their world will have passed them by. Their skills will have become outdated, loved ones aged, distant, or dead, friends moved on. Sure, an advanced civilization capable of near-c travel would certainly have great rehabilitation programs for their returning citizens; it might even honor them by hanging their ships in museums. Still, the physics of space travel would seem to make it a dreary business, the plot constrained and unforgiving.

(Now if the story's protagonist were to be a caricature of someone in the future who we can still relate with--perhaps a young, aloof outcast, set in her now ancient ways who reminds a future generation of long forgotten values--then we might use near-c travel, instead of the cryonic fridge, as the device that placed her there. But that would be another scifi genre.)

Perhaps we shouldn't be thinking of these alien visitors as space travelers at all; they're space-time travelers. No, they don't get to revisit the past; instead, they get to race forward into history. For all we know, they get to see the universe's chilly end. And our conception of a home planet, namely a place where a civilization is anchored to, is likely a tad bourgeois from their perspective.

Near-c Civilizations

Assuming our alien space-time travelers are in fact individuated, social beings (as opposed to mere extensions of some borg-like creature), how then are their civilizations organized? We're not ruminating here over such things as class hierarchy and such, but merely considering how its individuals interact. How do they keep time? Whatever the solution, they must be extra cautious with this dimension. For all the while they whiz back and forth across space, they can only race forward through "ambient" time.

To better appreciate the dynamics of near-c travel, let's consider two siblings on planet Ki who wish to embark on separate near-c journeys. They plan to rendezvous back on Ki after having each aged the same, say nine years. After much calculation, haggling and flight plan adjustments (their destinations are roughly the same distance), they agree to meet again after one hundred fifty-two years have elapsed back on Ki.

With near-c communities, a rendezvous involves not only specifying a time and place to meet, but also how old the parties will be when they meet. In our hypothetical example, the meeting time was given in local, Ki time, what I'm loosely calling ambient time, while each sibling's age was to be measured in their respective ship times. That the siblings planned to have aged exactly the same when they next met was just illustrative: maybe they ended up agreeing to age nine years, give or take a few.

So we see how two near-c travelers can possibly stay in touch; but can we extend it to a community? If the residents of Ki routinely travel to distant times and places at near-c speeds, then who's left to run the affairs of the planet they leave behind? Would there be any incentive to keep Ki humming? Maybe.

For if there's work to be done and goods to be traded, whether material or virtual, the ambient timers who choose to stay on Ki enjoy a huge advantage over their near-c brethren: though they age faster, or rather, because they age faster, they also get more done. If there's some sort of competition over limited societal resources, then, over time (anyone's time), these better placed (perhaps, generations of) ambient timers will corner those riches before their more youthful, less accomplished, near-c cousins can.

[Juxtapose that last paragraph against the near-c-ers perspective: harvesting technological change.]

On the Evolution of Intelligence

Let us now turn our attention to establishing an evolutionary narrative for these advanced extraterrestrial visitors. This exploration might both inform the setting in broad brushstrokes (the characteristics, diversity of the alien visitors, and how they came to be) and help lead the reader down a plausible path into an implausible setting.

(Though the typical scifi aficionado approaches a read with a healthy willingness to suspend disbelief, this goodwill is best not squandered. I think the near-future scifi genre owes some of its success to this same principle. Plots typically consume disbelief capital early on, say with the introduction one or two game changer technologies (The Truth Machine, Minority Report, I, Robot), which when grafted onto an otherwise familiar landscape, expose unexpected dichotomies, give rise to unintended consequences, present moral and philosophical challenges.)

If the emergence of intelligence marks an inflection point on the evolutionary path of life, then clearly these are early days here on earth, a four billion year old planet that of late (say the last ten thousand years) has hosted intelligent civilizations.

Elsewhere across the cosmos, our story goes, as indeed here in our milky way, conditions for the emergence of intelligence have been ripe in many a corner, and at many a time, both recently and in the distance past. We need not defend an estimate of how big this cosmological window in time is (you might need heavy elements, planets, and such): a mere billion year window should suffice for grounding a story in which many civilizations, perhaps most, survive their technological adolescence and advance to the near-c-er club.

But we are getting ahead of ourselves. The emergence of intelligence, the narrator explains, is a game changer not because of the outcome (intelligent, sentient beings), but because it marks the beginning of a change in process. The elemental drivers of the evolutionary process (natural selection, drift, etc.) are first mediated, then supervised, and eventually subsumed by a new driver, namely intelligent design.

Intelligent Machines

Every [intelligent] civilization, the story asserts, assuming it survives its early years, soon manufactures intelligent self-replicating machines. Here's an attempt at a half-believable sketch leading up to intelligent machines.

The Printer

 

If machine life was the next major evolutionary step after intelligent life, then the 3D printer must be the progenitor of all living machines. To be sure, the early models were not living at all; they were the agent, the primordial soup as it were, from which the new life form would emerge.

Some argue machine life begins at the point when the most advanced printers can only be constructed from other printed parts. Another view holds that early wet life industrialization marks the beginning of machine life. These arguments are well grounded, but we take a more practical approach: by the time wet life manufacturing is dominated by second order printed products, machine life has begun in embryonic form.

kk is the oldest documented kernel printer design by any wet life civilization that could print copies of itself. It could do very little else, of course, but it was the compiler that could now compile itself, the bootstrap on which ever more elaborate self replicating designs followed.

It's designers were well aware they had created a new life form: as long as intelligent wet life organisms found a design cute, there would always be versions of the object filling the real world. Though at the time (and place) it was widely acknowledged that a new evolutionary milestone had been crossed, it was discussed only in the abstract. After all, the printers could not grow without cooperating wet life.

But in every documented ecosystem, the technology soon overtakes the abstract. Printers become cheaper and ever more capable at printing at both the nano and macro scales. This ability to print at the nano scale facilitates the development of emergent capabilities. We see the printer designs start to flow out from nano scale features out to the macro scale.  Cultivating ever more individuated machines becomes a principal component of intelligent wet life economic activity.

If the printer was the physical embodiment of the this new life form, its DNA was the code that defined how to print it.

Actually, whether some such a narrative or another, one idea is that an intelligent machine's digital "DNA" not only describes its physical form, but also its mental (its learned) state. That is, it can print clones of itself, offsprings really, that each inherits the collective experience of its ancestors.

C Travel

But if it can clone itself locally, then perhaps an intelligent machine can also arrange to have a copy of itself printed at a remote location. As it beams its code to a printer parked at one of the remote galactic outposts, say a mere 20,000 light years away, the intelligent machine travels at the speed of light.

A troublesome side effect of this form of c travel is that you leave a copy of yourself behind.

~

We could go on, but I hope it's already clear you don't need to challenge physics with faster-than-c travel in order to write scifi about space faring aliens. Indeed it can be more interesting if you don't.

Related Stuff

Fermi's Paradox: "Where is everybody?"

Louis K. Scheffer (1994),  Machine Intelligence, the Cost of Interstellar Travel and Fermi's Paradox