by James Benford
I first talked to Jim Benford back in 2003, discussing his work (wih brother Gregory) on microwave beam propulsion. He had already run experiments at the Jet Propulsion Laboratory demonstrating acceleration on a lightsail using these techniques, and was then hoping to run an experiment on The Planetary Society’s ill-fated Cosmos 1. The founder of Microwave Sciences, Benford’s earlier work at Physics International led to the development of the largest high power microwave experimental facility in the country. Along with continuing work on sail beamed propulsion concepts, the physicist has been actively studying questions of SETI and METI, musing on the kind of beacons we might find and the motivations for building them. Herewith some thoughts inspired by recent discussions in these pages.
We explored the motives for a civilization broadcasting to the galaxy at large (which I call Beacons, as they’re not targeted at specific stars) in one of the two papers we did last year, which was extensively described on this site. It will be published soon in the archived literature, as but for now it’s at:
Searching for Cost Optimized Interstellar Beacons, Gregory Benford, James Benford, Dominic Benford, http://arxiv.org/abs/0810.3966, and has been submitted to Astrobiology.
Through most of its history, SETI has assumed a high-minded search for other lifeforms. But other motives are possible. The categories of motivations as we described them:
What could motivate a Beacon builder? Here we can only reason from our own historical experience. Other possible high intelligences on Earth (whales, dolphins, chimpanzees) do not have significant tool use, so they do not build lasting monuments. Sending messages over millennia or more connects with our own cultures. Human history suggests (Benford G., 1999, Deep Time, Harper Collins, New York) that there are two major categories of long-term messages that finite, mortal beings send across vast distances and time scales:
Kilroy Was Here. These can be signatures verging on graffiti. Names chiseled into walls have survived from ancient times. More recently, we sent compact disks on interplanetary probes, often bearing people’s names and short messages that can endure for millennia.
High Church. These are designed for durability, to convey the culture’s highest achievements. The essential message is this was the best we did; remember it.
A society that is stable over thousands of years may invest resources in either of these paths. The human prospect has advanced enormously in only a few centuries; the lifespan in the advanced societies has risen by 50% in each of the last two centuries. Living longer, we contemplate longer legacies. Time capsules and ever-proliferating monuments testify to our urge to leave behind tributes or works in concrete ways (sometimes literally). The urge to propagate culture quite probably will be a universal aspect of intelligent, technological, mortal species (Minsky, Marvin, 1985, in Extraterrestrials: Science and Alien Intelligence (Edward Regis, Ed.), Cambridge University Press, also at http://web.media.mit.edu/~minsky/papers/AlienIntelligence.html).
Image: A Kardashev Type III civilization imagined. Would a culture able to tap the vast power of its entire galaxy engage in beacon building? What can we imagine about its motives? Art by Jon Lomberg.
Thinking broadly, high-power transmitters might be built for wide variety of goals other than two-way communication driven by curiosity. For example:
- The Funeral Pyre: A civilization near the end of its life announces its existence.
- Ozymandias: Here the motivation is sheer pride; the Beacon announces the existence of a high civilization, even though it may be extinct, and the Beacon tended by robots. This recalls the classic Percy Bysshe Shelly lines,
And on the pedestal these words appear:
‘My name is Ozymandias, King of Kings;
Look on my works, Ye Mighty, and despair!’
Nothing beside remains. Round the decay
of that colossal wreck, boundless and bare,
The lone and level sands stretch far away.
- Help! Quite possibly societies that plan over time scales ~1000 years will foresee physical problems and wish to discover if others have surmounted them. An example is a civilization whose star is warming (as ours is), which may wish to move their planet outward with gravitational tugs. Many others are possible.
- Leakage Radiation: These are unintentional, much like objects left accidentally in ancient sites and uncovered long after. They do carry messages, even if inadvertent: technological fingerprints. These can be not merely radio and television broadcasts radiating isotropically, which are weak, but deep space radar and beaming of energy over solar system distances. This includes “industrial” spaceship launchers, beam-driven sails, “planetary defense” radars scanning for killer asteroids, and cosmic power beaming driving interstellar starships with beams of lasers, millimeter or microwaves. There are many ideas about such uses already in the literature (Benford, G. and Benford, J., 2006, “Power Beaming Concepts for Future Deep Space Exploration,” JBIS 59, pp. 104-107).
- Believe and Join Us: Religion may be a galactic commonplace; after all, it is here. Seeking converts is common, too, and electromagnetic preaching fits a frequent meme.
The point is that there can be many motives, with two-way communication only one of them. The METI signals we’ve sent from Earth are detectable for only very short distances on the scale of the galaxy, typically a light year. Therefore, higher powers and larger antenna areas are required for serious Beacons.
All SETI search strategies must assume something about the beacon builder. Our other paper of last year (Benford, J., Benford, G., & Benford, D., 2009, “Messaging with Cost Optimized Interstellar Beacons”, arxiv.org/abs/0810.3966, submitted to Astrobiology) made the argument that whatever the motivations, the driver in building METI transmitters on such scales will be economics.
While cultural passions can set goals, economics determines how they get done. Many long-term spectacular projects, such as the pyramids of Egypt, lasted only a century or two and then met economic limits. The Taj Mahal so taxed its province that the second, black Taj was never built. The grand cathedrals of medieval Europe suffered cost constraints and, to avoid swamping local economies, so took several centuries of large effort. Passion is temporary, while costs constrain long-term projects.
So, we should look at cost as the limiting factor that will tell us things about what we should be looking for in SETI searches.
Comments on this entry are closed.
Big Ear’s ‘Wow!’ signal might have been Leakage Radiation. The region had been subsequently observed with no positive observations since.
Anyone who thinks that much useful information can be got out of alien transmissions, could you please contribute some effort towards deciphering Rongorongo, or Linear A, or Epi-Olmec Script? After all the writers have a lot more in common with present-day humanity than an alien civilisation ever will, so you’d expect them to be a lot more easily translatable than any alien signal…
Yeah, if (a big if) there are other high-tech worlds but they’re not deliberately trying to communicate we should expect a number of ‘Wow!’ type events as we develop more sensitive detection methods. The requirement for repetition may be too stringent for the situations we actually encounter.
Rongorongo, or Linear A, or Epi-Olmec Scrip were not intended to communicate to minds outside the culture that made them. Carefully designed “anti-codes”, intended for alien intelligence to receive, may be far easier to read and understand.
By the way, Rongorongo scripts from Rapa Nui are thought by many anthropologists to be meaningless faux scripts, created by the Rapa Nui people in imitation of the writing of the powerful Europeans invading the Pacific. There are no written languages among indigenous Pacific Islanders, probably because there was no paper, parchment, or other light, flexible, and durable materials on which to write.
(Could some ETs with a bizarre sense of humor send meaningless bursts of apparently content-laden code intended to drive recipients crazy?)
A beacon could also be a warning buoy. e.g., Stay the hell away from this region of space: It’s a space “tar pit” / There be Dragons here / Infectious biological agents present / High levels of some kind of hard to detect yet lethal radiation / Toxic Waste Dump / Our place, keep out / Warring lifeforms / Other bad stuff.
I do agree though that we should be able to decipher the various writings of our own species before we’d stand a chance at deciphering alien communications, but then the guys who were writing on Easter Island were writing for their own purposes and not as an attempt to reach out to other cultures at other times. If they had tried to do this we would likely find some key to help us decipher it.
andy said on September 22, 2009 at 14:01:
“Anyone who thinks that much useful information can be got out of alien transmissions, could you please contribute some effort towards deciphering Rongorongo, or Linear A, or Epi-Olmec Script? After all the writers have a lot more in common with present-day humanity than an alien civilisation ever will, so you’d expect them to be a lot more easily translatable than any alien signal…”
It will be interesting to see if humanity ultimately benefits more from
deciphering the languages of long-past cultures from our species who
occupied specific regions of this one planet or the potential information
in a message from an alien and possibly still thriving society occupying
another region of the Milky Way galaxy.
I say this as a long-time student of history. I also think that with almost 7
billion people on Earth, there should be more than enough members who
are willing and able to search for, study, decipher, and comprehend both
types of languages and cultures.
I don’t think that considering the economics of constructing a beacon makes all that much sense. Two hundred years ago, the idea of anything being sent into space was beyond priceless, and two hundred years from now it will may very well be dirt cheap. How would we be able to judge what economic limitations another civilization would encounter? Furthermore, there’s no proof that a short attention-span is a universal aspect of intelligent life. That being said, I think it’s a really good idea to figure out how much we can assume about ETI in order to find them, and it’s good to start somewhere.
Andy, if we come across accidental or incidental alien signals I agree they could be indecipherable, but a deliberate METI beacon would, by its very definition be something that the civilization sending it would design to be understood by the receiver. It’s not that hard to design a stepladder approach from first principles to some fairly sophisticated level of common understanding, when that is the objective of the message.
But even accidental signals could be cracked, depending on the contents. The movie “The Day The Earth Stood Still” was beamed to Alpha Centuari last year. If there happened to be someone out there with the ability to record the signal as it came in three years from now, if they figured out that it was a video format (probably not too hard) then they would be able to glean a great deal about Earth and our culture even if they didn’t understand a word of the movie script itself.
James, I have read through the paper and it’s very interesting. I do have a question about one observation that you make:
How concrete is this 1000LY limit? Would it still apply even if we had a whole fleet of gigantic planet-finder interferometers deployed in the outer solar system (say 500 years from now)? I ask because observing and cataloging our local region of the galaxy from our own solar system is obviously going to be orders of magnitude faster and cheaper than using interstellar probes, but this is the first time I have seen anyone put a figure to the maximum distance we might be able to detect life through spectrographic means (though the Kepler team does mention that there might be issues with Zodiacal light if we ever develop the means to follow up on some of the Earth-like planet transits they discover).
I was happy to see this section (I was going to ask about it before I came to it!). It is an interesting point. We’re essentially trying to figure out what the METI beacon builders might do in response (in part) to their figuring out about what we might do as lowly SETI participants. If this is true, then it should give us cause for optimism that we will find the beacons sooner rather than later—if they exist, of course.
Giving this some thought for a few years, wouldn’t it be relatively easier, if an advanced civilization wanted to broadcast a signal to other civilizations across the galaxy they would use a “natural beacon” such as a pulsar or black hole? Despite distances, a pulsar or a black hole would be a natural place for any advanced civilization to point their telescopes at for the sake of study. And it would only take relatively small amounts of matter collided with either to radiate a powerful enough signal to be detected from a large distance, such a system would be more of a Galactic Morse code .
There’s always the old SF horror-story idea of the Langford Hack – a mind-virus that uploads through the optic nerve. Or the DNA virus code that seemingly does nothing until it has invaded the whole ecosphere.
“But even accidental signals could be cracked, depending on the contents. The movie “The Day The Earth Stood Still” was beamed to Alpha Centuari last year. If there happened to be someone out there with the ability to record the signal as it came in three years from now, if they figured out that it was a video format (probably not too hard) then they would be able to glean a great deal about Earth and our culture even if they didn’t understand a word of the movie script itself.”
It is probably a good thing that any ETI should not understand that remake
because it is about an advanced alien species condemning humanity to
extinction due to the way we have treated Earth – which should make one
want to ask the superior-acting aliens how they came about their technological
civilization without having to mine for any minerals to build things or chop
down any forests and displace their animals to make buildings and such.
Greg said on September 22, 2009 at 23:15:
“Giving this some thought for a few years, wouldn’t it be relatively easier, if an advanced civilization wanted to broadcast a signal to other civilizations across the galaxy they would use a “natural beacon” such as a pulsar or black hole? Despite distances, a pulsar or a black hole would be a natural place for any advanced civilization to point their telescopes at for the sake of study. And it would only take relatively small amounts of matter collided with either to radiate a powerful enough signal to be detected from a large distance, such a system would be more of a Galactic Morse code.”
Greg, scroll down a bit to the topic titled “The Why of METI and SETI” and
read the later comments on how aliens might use supernovae as attention-
getters for anyone observing those natural celestial phenomena.
And then scroll up to read about how we should monitor dying and dead suns
in case any of their former inhabitants decided to let us know they once lived
there and what they were all about.
Jon Lomberg said:
“(Could some ETs with a bizarre sense of humor send meaningless bursts of apparently content-laden code intended to drive recipients crazy?)”
In the second item of my list on why aliens might signal us two topics before
this one, I bring up the fact that humor is often left out of the equation when
it comes to the motives of ETI.
At the risk of being anthropomorphic, I think humor may be both a sign of
intelligence in a species and a survival mechanism, for as numerous authors
have pointed out, it is tragic situations that we normally laugh about as a
way to cope with them.
Look at the Doritos advertisement sent by the UK or some of the comments
made by the participants of the recent Hello from Earth broadcast. A lot of
them were humorous in nature and even though the jokes were really aimed
at humanity, they were sent to the stars just the same.
Maybe advanced ETI think it is great sport to make fun of lower intelligences
and pull practical jokes on them, perhaps out of ennui or just to feel that much
more superior about themselves.
To add to the above about the universal possibilities of humor, as I recall
even one of the later images from the Voyager Interstellar Record was
deliberately meant to be humorous in nature.
It was this one, depicting a vehicle exploring the Antarctic in 1958 stuck
precariously over a crevasse:
As I recall from the 1978 book about the Record titled Murmurs of Earth, it
was meant to show that humans weren’t perfect either (in a hopefully non-
threatening way), and that the recipients may have found themselves in
similar situations while exploring the strange environments of other worlds.
Of course who knows what an alien mind might find to be funny or not.
Would a machine-based intelligence have a sense of humor, or do you have
to be organic to get a joke?
Larry, if you described our “humorous” Voyager Record photo from memory, I am impressed. You nailed it. I hope this photo illustrates the point that technological situations (a stuck vehicle in this case) may be more widely shared than biological structures and thius easier to understand. So no matter what ET looks like or thinks like, mud is mud and stuck is stuck. The general point is that in thinking about how we might communicate with ET, we may be on firmer ground reasoning from technological considerations rather than unknowable motivations. This is well illustrated by the triple Benfords’ work on technological boundaries of beacons.
Biological and cultural issues are central to this issue. It’s my hope that I will have time and energy to write about both of these soon — right now I must finish my second piece for H+ magazine!
But relative to an alien civilisation, we are the culture that made them. They were not designed to be forgotten either.
I disagree with this assertion. You have various conventions about how to represent numbers (e.g. as an example least significant digit first versus most significant digit first, and remember the aliens won’t know that U+FFFE is a guaranteed non-assigned codepoint), what the “natural” order to represent a sequence is, whether signal on represents 1 or 0 (if we restrict our hypothetical aliens to binary). Mathematics may be universal but transmittable representations are not…
ljk said on September 23, 2009 at 9:38;
“Greg, scroll down a bit to the topic titled “The Why of METI and SETI” and
read the later comments on how aliens might use supernovae as attention-
getters for anyone observing those natural celestial phenomena.
And then scroll up to read about how we should monitor dying and dead suns
in case any of their former inhabitants decided to let us know they once lived
there and what they were all about.”
I did see that, sincerest thanks. What I’m getting at is slightly different and expanded on. The time an automated spacecraft can stay in orbit around a black hole or pulsar could easily be centuries, millennia or longer, as compared to a supernova which would last for a few days at best. The ability to loiter around these objects (black holes, etc.) would increase the likelihood that a signal would be detected as the chances someone would be looking that way would be better.
Anyway, just trying to add more to the discussion.
“a mind-virus that uploads through the optic nerve…”
We should immediately cease all television transmissions of “American Idol” then, lest we infect alien populations with this particular germ.
“Mathematics may be universal but transmittable representations are not…”
If you mean would an ETI who does not speak or know anything about English
or other human languages and related concepts would likely not recognize
the Arabic-based numeric system we use, you are correct.
However, I don’t think it is terribly difficult to ask of a technological society
to recognize a basic counting scheme if you show them a simple object and
then ascending multiples of that object adding one at a time.
The Voyager Record image set has that very concept early on as shown here:
Unless there are aliens that are so bizarre that they somehow don’t perceive
counting or other rudimentary math as we do, the kinds of ETI we are looking
for, one with a technological society that includes various types of telescopes,
should be able to comprehend basic math if shown in a symbolic way as a guide.
Marvin Minsky wrote a paper on this subject in 1985 showing that intelligences
which develop technology will have to do so in certain ways that are mandatory
across the board no matter where they are:
As much as I find ancient human cultures of great interest and know there is
still much to learn from them (a lot of preserved documents still sit in museum
and library basements waiting to be refound and translated), I am hoping and
naturally assuming that any ETI which send humanity deliberate messages will
include in their transmissions information not only about themselves but
aspects of their region of the galaxy that we would not be able to learn of
otherwise while stuck on Earth. Such data could be vitally important for
human survival and progress.
Please note I am referring to ETI messages sent to us on purpose in a manner
designed to foster interspecies communication and information exchange,
not an accidental transmission pickup or the prelude to an attack.
“What I’m getting at is slightly different and expanded on. The time an automated spacecraft can stay in orbit around a black hole or pulsar could easily be centuries, millennia or longer, as compared to a supernova which would last for a few days at best. The ability to loiter around these objects (black holes, etc.) would increase the likelihood that a signal would be detected as the chances someone would be looking that way would be better.”
We have known since 1990 that whole planets in some form can survive a
supernova event, when the first exoworlds were discovered around several
pulsars. So if a society living in such a system had the ability to build a means
to transmit their knowledge into the galaxy, they could keep it going even
after the stellar explosion by burying their data storage and transmitting
equipment deep under the surface of their planet or a planetoid for its
protection (would a comet survive a supernova? I know the ice would
make a great radiation shield, assuming the comet would not be melted or
vaporized by the blast).
So assuming the ETI’s records and beacon survive the blast, they could
continue to transmit once things settle down a bit in their old neighborhood.
And they would have a pulsar and a expanding debris cloud to help attract
attention to the rest of the Universe.
I know one could ask if the aliens went to the trouble of preserving their
knowledge underground, why don’t they just move their whole society
underground too and wait out the explosion? Besides the distinct
possibility that preserving a whole civilization under those circumstances
might be a bit of a challenge (the surface would be fried and bathed in
serious radiation; living underground for generations might not be a
pleasant situation for many of the inhabitants and society could become
destabilized from this), maybe they could survive that way (their children
and future generations would not only any other lifestyle) and the data
beacon could serve as a way to ask for help or to become a way to preserve
their memory should the survival attempt fail.
We should also check red giants and white dwarfs for the same reason.
For those ETI which can escape their dying star systems, we should
monitor for the propulsion signatures made by starship engines such as
an excess of gamma rays in the event they are not signalling the galaxy.
But as I also said about supernova, ETI signals do not need to come from
a dying society in such a system. A distant one between the SN and Earth
could use the natural cosmic beacon as an attention-getter. Now whether
any astronomers on this planet monitoring a supernova event will ever
bother to check for artificial signals, that is another matter. Are there
any SETI projects observing SNs for such signals?
The environment around a black hole (away from the event horizon and
churning debris disk, of course) would make a great place for an advanced
society to live about. Did you know that if they throw their garbage into a
black hole they will get back more energy than they put in? Natural
renewable energy source right there plus they solve their trash problem.
“But relative to an alien civilisation, we are the culture that made them. ”
I do not agree that this is a proper generalization. We cannot assume from an N of 1 that ALL human civilizations and cultures would be more comprehensible to each other than ALL alien civilizations and cultures. If the aliens are not culturally monolithic, then it is entirely possible that within the distribution of the cultural practices of one species, some may be more similar(and comprehensible) to some of the other species than others of the same species at the opposite extreme of the range of variation.
An alien culture at a similar level of technical advancement to us would be expected to share more in common with us in certain aspects of scientific knowledge, technical expertise and understanding, and possibly even social organization, than we may share with other human cultures far removed from ourselves in place and time. So we certainly cannot assume that all alien communications will be guaranteed to be harder to decipher for us than any communications from other humans from cultures very different from our own.
>Rongorongo, or Linear A, or Epi-Olmec Scrip were not intended to
>communicate to minds outside the culture that made them
“But relative to an alien civilisation, we are the culture that made them. They were not designed to be forgotten either.”
amphiox: “I do not agree that this is a proper generalization.”
I do not agree either, but because of different reasons.
It is *not* our culture, members of which have produced those written works. Just because there are no cultural traditions connecting “those” different cultures to our culture, we are not able to understand and translate.
See also two comments of mine about the article “The Why of METI and SETI” by Larry Klaes, regarding the difficulty and — for some rather freaky alien cultures — impossibility of communication, being the result of different evolutions, histories, and cultures.
I don’t think that considering the economics of constructing a beacon makes all that much sense. Two hundred years ago, the idea of anything being sent into space was beyond priceless, and two hundred years from now it will may very well be dirt-cheap. How would we be able to judge what economic limitations another civilization would encounter?
Space travel was not ‘priceless’ 200 years ago; it was unpriceable because we didn’t know how to do it. My point is that we do know how to build Beacons, and cost is a design constraint used widely here for large microwave systems. So let’s use that knowledge/experience to see what a cost-constrained Beacon will look like, using our optimizing methods. See our Messaging paper for a systematic method.
Our second paper, ‘Searching…” deals with what ET would do. That evolution will select for economy of resources is an established principle in evolutionary theory, whatever the life form (Williams, George C., Adaptation And Natural Selection, Princeton, 1966). Tullock (The Economics of Non-Human Societies, pp. 72-83, Pallas Press, Tucson, 1994) argues that social species evolve to an equilibrium in which each species unconsciously carries out “environmental coordination” which can follow rules like those of a market, especially among plants. He gives many such cases. Economics is commonly used to model insect behavior, for example. Economics matters.
You ask ‘How concrete is this 1000 ly limit?’, talking about the ability to see spectral lines from planets at galactic distances. It’s because of scattering by dust in the disk: beyond 1000 ly scattering and extinction makes targeting oxygen-bearing planets difficult. Attenuation is about 1/100 beyond 1000 ly. Moving from the far infrared (10 mm) helps. See SETI 2020, pg. 62 and references therein.
On cooperation between Beacons and receivers, Robin Hanson of George Mason University, following up on our two METI/SETI papers, has assigned a grad student to do a game theory-based analysis of Beacon/receiver strategies. We’ll see what comes of that!
There will be a revised and expanded versions of both papers soon, the final versions before refereed journal publication.
I think the cost of the energy required to modulate pulsar output would dwarf the cost of building a microwave or laser Beacon.
Thanks for the reference, James. I guess 1000 LY isn’t so bad for starters :-)
A quick back of the envelope calculation would indicate that there are at least 10 million star systems within that distance from Earth, which gives us an very decent sample to work with once we have the equipment to begin the routine detection and imaging of terrestrial planets in other systems.
The key point is relative to an alien culture. We have far more shared context with these ancient cultures than we do with an alien civilisation – we are able to identify species and places in their art in a way that we could not do at a distance of many light years, in some cases we have related cultures to compare to with perhaps related languages, etc. With an alien culture, you start from scratch.
Yes, and if are we receive are obscure snippets of random information–the equivalent of the odd snippet or two of ancient writings on shards of pottery and tablets, then we will have almost no hope of understanding it.
But, what after a decade of trying we discover that what’s we’re receiving is in the format of a TV broadcast and we decipher the frames and start getting a partial picture of life on their planet? Once you can observe you can begin to interpret. It still might not make much sense but at least there’s now a chance. And the more data you have in that format, the better those chances are.
Finally, if the aliens are deliberately trying to make themselves understood in those signals, then the information is likely to be ordered or organized in some way. That organization might not be easy to understand, given profound cultural differences, it’s really not too hard to imagine schemes that ease the conveyance of basic information about your species.
I think pictorial representations will be key in such circumstances. On a very basic level, you can broadcast the dimensions of a picture (in pixels) and then a stream of data — perhaps organized as lines with gaps in between transmission — making up a picture or diagram with the dimensions you specified, and go from there.
Maybe. Then again, you never know… compare figures 5 and 7 in this article… oh dear.
I have read (sorry, I don’t remember the source — I read so much ;-), that anthropologists recognized, that by observing a culture from the distance only without sharing everyday live, they are able to understand this culture not very far but only up to a certain insurmountable limit. This happened to the anthropologists, as far as I remember, in the 1960s and 1970s, when they researched so called primitive societies. Yes, some even tried it like biologists observing animals: in a hideaway in the trees.
(The 1960s and 1970s have been something like a golden age for the social sciences, I think; everything seems possible, money was available, some saw themself as social engineers.)
Another interesting point, when “observing” from a great distance only, is, that there exist artefacts of certain cultures of the past — especially cultures without script or with one we are not able to translate. For us today — in the distance — these artefacts are works of art. But historians say, that we don’t really know, whether the people in those cultures considered those artefacts as being works of art too, or religious devices, or both, or just beautiful, or something completely different. The first examples are Stone Age artefacts like sculptures and paintings of prototype females and of contemporary animals. Other prominent examples are those objects from Africa which led Pablo Picasso to innovations in his own art.