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The human race is special

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Introduction

This page presents the highlights of a discussion which took place in the USENET discussion group talk.origins for the most part around August 1997. Sorry about the length, but it should be easy to read, thought-provoking and perhaps a little fun.

MY ARGUMENT IN A NUTSHELL: If the human race is not special, then, in our galaxy of 100 billion solar systems there must be many similar or superior races, many of whom will have had a big head start on us - some by billions of years, even. Almost all of them would have made their presence known via radio communication or space travel, since we humans are doing these things, and we are not special.

Their presence has not been made known.

This forces us to conclude the human race is special.

The logic exercised here is given the name "modus tollens": IF (IF A THEN B) AND NOT(B) THEN NOT(A).

MODUS TOLLENS REFRESHER COURSE: Jack makes this true statement: "If I win the lottery, I will go to Paris." Jack does not go to Paris. We can conclude definitely that Jack did not win the lottery.

WHAT I MEAN BY SPECIAL: When forced to take a very close look, I see I use the word in two ways, both involving extraordinary rareness:

  1. special = unique or very, very rare, numberwise.
  2. special = having a behavioral trait that is unique or very, very rare.

For example, if of the billions of animals on earth, there were only 1 kangaroo (or even a few) I would consider a kangaroo "special".

If there are millions of kangaroos, but only one (or even a few) plays chess, I would consider that kangaroo "special".

There can't be any problem with that, can there?

PARTICIPANTS:

    DS = me = Donald Sauter.
    TO = talk.origins participants.
    TT = Timothy J. Thompson, NASA/JPL scientist.  Tim's comments are 
         explicitly labeled.  He worked on the SETI project and his 
         contributions to this discussion were major.  


My letter

The basis for the discussion was a letter I sent to the Washington Times, dated Dec 29 1996. It was not published.

Back in August 1996, the discovery of evidence of life on Mars was reported. This has given heavy-duty thinkers several months to glimpse the implications. As far as I can tell, nobody has come close.

Your end-of-the-year science article, "The fact of life appears universal" (29Dec96), adheres to the standard line of reasoning that the discovery makes us humans less special. A scientist (William Cochran, University of Texas in Austin) is quoted as saying, "It actually shows that we're not very special. Anytime that we've thought that we here on our Earth and our solar system and our sun have been special in any way, we've been proven wrong."

Humans are intelligent enough to have developed the technology to send out radio waves into our neighborhood of the galaxy. We've even taken our first baby steps sending out spacecraft. But we ourselves have not been contacted by any other civilizations, either by a visit or by electromagnetic communication. That fact presents not a mere problem for people arguing we are not special - it is absolutely fatal to their argument.

There are a hundred billion stars in our galaxy. If, as the above scientist assures us, there is nothing special about our solar system, we would expect life to appear on a planet in most solar systems. That makes a hundred billion life forms - give or take - which are top dog on their planet, and yet too primitive to contact us. We are the only ones reaching out. That makes us one in 100 billion. The only way for a logical, mathematical, scientific mind to not be staggered by that is to completely disengage itself.

Actually, the discovery of life elsewhere in our own solar system makes us more special. Now we find that life is so irrepressible that it will probably appear on 2 or more planets in every solar system. All of a sudden, there are twice as many brainiest life forms too stupid to even send a little message saying "Hi". All of a sudden, we are 1 in 200 billion. All of a sudden, we are twice as incomprehensibly unique.

There are explanations as to why we seem to be alone. Scientists like Carl Sagan tell us, sure, there are a 100 billion stars, but only so many are in the right age range, and only so many of those emit the right type of radiation, and only so many of those have the right sort of planet at just the right distance. And when life does develop it may be wiped out before it evolves into advanced beings. And only a fraction of intelligent species will be inclined to civilize, and then go on to develop science and technology. And on top of all that, civilizations only last so long, what with wars and pollution and all, you know. We probably missed their call.

Excuse me, sir, but explaining why we are unique in no way diminishes our uniqueness. Not to mention that there are some suspect links in the logical chain. A species advancing far enough to flit around the galaxy and then dying out strains credibility. You would suppose that when even one alien race gets that far they would populate the galaxy in short order.

Notice the argument here has nothing to do with personal opinion or religion. It is based solely on numbers and probability.

Let me try to guess why those who are supposedly qualified to explain the matter to us have missed the boat so badly. It seems we have difficulty seeing beyond the way things are for us. We're just taking our first steps, so other alien civilizations probably are too, right?

When there are potentially billions of them, and they've had billions of years to beat us to the punch? No way.

More fundamentally, the problem is one of grasping huge numbers. The immensity of a 100 billion is outside of human experience. We are used to repeated addition, but not repeated multiplication. We imprecisely think of a million as a few thousands lumped together, and a billion as a few millions lumped together. After all, it's only a few extra zeros tacked on the end. So, a few thousand, a few billion - what's the difference?

If there were only a million stars in the galaxy, our uniqueness would be astounding enough. But 100 billion is so huge that even if we were in regular communication and commerce with "only" a thousand alien civilizations, trying to fathom our inclusion in such an exclusive group would still cause mental distress. Perhaps it is a merciful thing that we can't conceive of a 100 billion.

Many scientists are skeptical the evidence from the meteorite indicates Martian life. (I personally wouldn't be surprised if the rock had been kicked off the Earth a while back.) If they are right, we are back to square one. You can return to believing that life exists only on Earth, or that life is rampant throughout the universe, or anything in between.

Where you don't have a choice is in regards to the specialness of humans. If there are others out there, it is inconceivable - literally - that in billions of years nobody has left any sort of sign.

We humans became technological only a few decades ago and already we're making our marks.


DIALOG WITH TALK.ORIGINS: Sometime later I posted it to talk.origins for feedback. The dialog is laid out conversationally, with the original letter indented and labeled DS1.

SNEAK PREVIEW OF RESULTS: In spite of my unflagging certainty that what I am saying is simple, unassailable logic, not a single person who responded agreed with any aspect of my argument.

SOMETHING TO LOOK OUT FOR: In many of the rebuttals to my argument it is obvious that the respondent is hung up on the difficulty or unlikeliness of stumbling on a hypothetical single alien civilization, ignoring or oblivious to the inescapable conclusion that there must be billions of them out there if life is irrepressible and evolution is inexorable. Responding to that misguided notion accounts for most of the redundancy you will find here.

FROM NOW ON: Wherever I use words like "billions of advanced alien civilizations" there is an implied "which must exist if life is irrepressible and evolution is inexorable."

The letter with interleaved comments

DS1: Back in August 1996, the discovery of evidence of life on Mars was reported. This has given heavy-duty thinkers several months to glimpse the implications. As far as I can tell, nobody has come close.

Your end-of-the-year science article, "The fact of life appears universal" (29Dec96), adheres to the standard line of reasoning that the discovery makes us humans less special. A scientist (William Cochran, University of Texas in Austin) is quoted as saying, "It actually shows that we're not very special. Anytime that we've thought that we here on our Earth and our solar system and our sun have been special in any way, we've been proven wrong."

Humans are intelligent enough to have developed the technology to send out radio waves into our neighborhood of the galaxy. We've even taken our first baby steps sending out spacecraft. But we ourselves have not been contacted by any other civilizations, either by a visit or by electromagnetic communication. That fact presents not a mere problem for people arguing we are not special - it is absolutely fatal to their argument.

(Jump to the next chunk of this letter?)

TO: You are making a huge assumption here based on no evidence. Just because another civilization has not contacted us does not mean they are not trying.

DS2: Any particular civilization trying and failing to contact us is one thing; billions of civilizations failing is another.

TO: The universe is absolutely HUGE. It takes a LONG time for transmissions to travel from place to place. Suppose an alien race is just now receiving transmissions from 30 years ago. It would take their transmissions 30 years to reach us.

DS2: Yes, the number of civilizations who could have sent a reply back to us by now may be limited, but why aren't we receiving unsolicited transmissions sent out by civilizations while we were inventing the wheel?

TT: You don't know that "we have not been contacted". If, 200 years ago, some alien looking for CB buddies called the earth on his short-wave, there would have been no answer, and we would never know he had been here.

DS2: Even if the particular alien civilization you refer to has an attention deficit disorder and gives up after the first try or two, there should be many others who surely wouldn't give up so easily. And even if every civilization just spent a few days (an absurdly extreme assumption) at actively trying to contact other aliens, we should be catching some of those broadcasts. (Multiply a few days by 100 billion.)

TT: How could we be contacted if we aren't listening? Only by someone willing to break into our own current communications systems and aggressively court communication. But that is a judgement call based on trying to psychoanalyze the alien mind. We have no way of knowing whether or not this would ever be likely to happen, and asserting that there are no aliens because it has not happened, is not reasonable.

DS2: Isn't the mere fact that the idea occurred to you enough to suggest very strongly that it would occur to other advanced alien civilizations, some of whom should have the means to "aggressively court communication"? If this idea can't occur to the billions of alien civilizations, that makes humans special. If there are reasons why implementing the idea is a physical impossibility, let's hear them.

TO: You forgot one important point: electromagnetic communication is probably only used a couple centuries before it is displaced by more advanced communication. So you have to point at the right star at the right time, a couple centuries is a very, very small window in the billions of years of the universe existence.

DS2: Not the right star, but billions of stars hosting advanced alien civilizations. Also, you are implying that advanced civilizations will lose their curiosity about other civilizations the moment they go to "advanced" communication. Is there any justification for that claim? Is there any reason to believe humans will?

TO: It would be like if today on a small island in the pacific a group of natives were looking for smoke signals in the distance, seeing none the natives would conclude that they are alone. They have taken their first baby steps rowing to nearby islands, but saw nothing. They would have no way to detect the dense EMF in the air, the occasional airplane passing by would be just a normal cosmic event.

DS2: What makes your analogy weak is that a Pacific island culture having a scientific or intellectual curiosity about other cultures would surely be intelligent enough to recognize passing ships and planes as evidence of higher intelligence. Furthermore, what small Pacific island tribe hasn't been visited - many times over - by "advanced alien civilizations" from universe Earth?

TO: At our current level of technology we could only receive signals from the closest stars, unless they were going out of their way to try to be heard. And why should they do that? Just to help out us poor unfortunate emerging civilizations?

DS2: They should go "out of their way to try to be heard" because of their curiosity about other alien civilizations. Humans have this curiosity. We have sent out signals purely for the sake of trying to get the attention of alien civilizations. If we are the only ones, then that makes us special.

Given that they are "going out of their way", we should be receiving signals from solar systems throughout the galaxy, not just the nearby ones.

SETI pioneer Frank Drake believes (p149), "we could well expect to see a wide diversity in the maximum powers transmitted by alien civilizations. If even a tiny percentage of extraterrestrials had reached superior heights of technological sophistication... [and] they were separated from us by enormous distances, they would still outshine more modest civilizations nearer to us - and by their brightness be the more readily detectable."

Frank Drake and Carl Sagan carried out such a search in 1975,1977. They searched four galaxies that lay just beyond the Milky Way. "Carl and I would scan hundreds of billions of distant [stars] in practically no time at all. If there were but one supercivilization in a galaxy, we would find it."

Drake describes Sagan's evident disappointment as the search proceeded (p151): "Even the first half-hour of our galaxy-combing strategy had let us look at ten billion stars. Perhaps that should have been enough. When a full hour had passed and we still hadn't found anything, I could sense Carl's disappointment. After a few days he was even a little bored by the sight of the green dots appearing uneventfully on the screen." (See further remarks below regarding SETI projects.)

TO: We didn't even know radio waves existed until the last century. Maybe anyone who's anyone in the galactic society page communicates with t-band gravity waves using multi-synchronous phase modulation at 193.257 terrahertz (or was it 193.258?).

DS2: If, of the billions of advanced alien civilizations, we are the only ones who discovered radio waves or put them to use in communications, then that makes us special.

TO: Consider that out of the 4 billion-year history of life on earth we have been looking for signals for the last what - 15 years? We could just as well have evolved to this level of technology a billion years sooner or a billion years later.

DS2: Thanks. You agree that advanced alien civilizations may have developed billions of years ago. Never mind that some of them should have figured out a way to get our attention - through our kitchen radios, maybe - even before we started actively searching; but, even assuming they couldn't do that, there should be signals galore when we do start our search. Why should it take even 15 days - or 15 minutes?

TO: How long could any technologically advanced civilization last? Given how quickly events unfold in this age of technology, what are the chances that we will make it another thousand years, let alone a million or a billion years. It could be that all civilizations either destroy themselves eventually, ...

DS2: I don't buy into that anthropomorphic "war and pollution are sure to wipe out an advanced civilization" business. (I say anthropomorphic even though it's not a certainty it will happen to humans.) I feel that the vast, vast majority of advanced alien civilizations would have no trouble lasting indefinitely, even surviving their own sun going nova. (We've already taken our first steps into space, and we've only been technological for measly decades.) To ward off this gloom and doom, all humans need to do is limit the population.

TO: ... or pack up and move to the galactic "downtown" which is too far away for us to hear anything, or they turn into glowing energy creatures who communicate instantaneously using photons with linked quantum states.

DS2: If, of the billions of advanced alien civilizations, humans are the only ones who haven't moved to the galactic "downtown" or turned into glowing energy creatures, then that makes us special.

DS1 [continuation of the original letter to the editor]: There are a hundred billion stars in our galaxy. If, as the above scientist assures us, there is nothing special about our solar system, we would expect life to appear on a planet in most solar systems. That makes a hundred billion life forms - give or take - which are top dog on their planet, and yet too primitive to contact us. We are the only ones reaching out. That makes us one in 100 billion. The only way for a logical, mathematical, scientific mind to not be staggered by that is to completely disengage itself.

(Jump forward to the next chunk of this letter, or back to the beginning of it?)

TO: Too primitive to contact us??? Even if another species was on the same technological level as us, it would be very, very difficult for them to contact us. You are also ASSUMING they are more primitive than us.

DS2: Again, you are focused on one other alien species. If we are not special, then there are billions. Almost all of them would be more technologically advanced, since we are only getting started. Reread what you wrote and you will see that it is you who has trouble accepting another species could reach our level. Your words indicate a belief that humans are special for their technological achievements.

I am not assuming the aliens are more primitive than us. Assuming they exist at all, I am logically deducing they must be more primitive. See "my argument in a nutshell" at the beginning. If they weren't, we would hear from them. We don't. Invoke modus tollens here.

DS1 [continuation of the original letter to the editor]: Actually, the discovery of life elsewhere in our own solar system makes us more special. Now we find that life is so irrepressible that it will probably appear on 2 or more planets in every solar system. All of a sudden, there are twice as many brainiest life forms too stupid to even send a little message saying "Hi". All of a sudden, we are 1 in 200 billion. All of a sudden, we are twice as incomprehensibly unique.

(Jump forward to the next chunk of this letter, or back to the beginning of it?)

TO: Why are you insisting that they contact US first? We haven't done a whole lot to contact them.

DS2: I'm not insisting that a single, particular advanced alien civilization contact us, just that any of the billions do - either intentionally or inadvertantly. Why I would expect that they contact us first is (as I have said before) we've only been at it a few decades; some of them will have been at it a few billion years.

TO: Interstellar travel may well be impossible.

DS2: Can anybody give one reason for believing interstellar travel to be impossible? That's a mighty strong word - especially in light of us already taking our first steps.

DS1 [continuation of the original letter to the editor]: There are explanations as to why we seem to be alone. Scientists like Carl Sagan tell us, sure, there are a 100 billion stars, but only so many are in the right age range, and only so many of those emit the right type of radiation, and only so many of those have the right sort of planet at just the right distance. And when life does develop it may be wiped out before it evolves into advanced beings. And only a fraction of intelligent species will be inclined to civilize, and then go on to develop science and technology. And on top of all that, civilizations only last so long, what with wars and pollution and all, you know. We probably missed their call.

Excuse me, sir, but explaining why we are unique in no way diminishes our uniqueness. Not to mention that there are some suspect links in the logical chain. A species advancing far enough to flit around the galaxy and then dying out strains credibility. You would suppose that when even one alien race gets that far they would populate the galaxy in short order.

(Jump forward to the next chunk of this letter, or back to the beginning of it?)

TO: Not really. The US used to have flocks of BILLIONS of passenger pigeons flying around. Now they are extinct.

DS2: Your analogy is a disaster for your side. Of the millions of species co-existing with the passenger pigeon, how many didn't become extinct?

TO: Let's not forget Einstein. Travel outside of one's local area might be completely impractical no matter how advanced our technology.

DS2: Special relativity doesn't put any lower bound on the travel time, by your own watch, to anywhere in the universe. If you've got the energy to burn, you can get anywhere in a blink.

DS1 [continuation of the original letter to the editor]: Notice the argument here has nothing to do with personal opinion or religion. It is based solely on numbers and probability.

(Jump forward to the next chunk of this letter, or back to the beginning of it?)

TO: Boy, if I had a nickel for every religious nut that has said that! (Not to imply that you are one - it just sounded so familiar.)

TT: Self deception, your arguments are woefully inadequate in terms of probability and numbers. The fact is that we really only know for sure that life exists in one place in the universe, the one we inhabit. One data point does not make much of a database for probability and statistics. I might also point out that you actually do not include any of the probability and statistics you are talking about. What probabilities did you calculate? Other than a vague reference to "one in a hundred billion" I didn't see any probability calculations.

DS2: Sorry if it's a disappointment, but that's about the extent of it. If life is irrepressible and evolution is inexorable (sorry for the broken record), then there should be 100 billion civilizations like us in our galaxy alone. If you refuse to accept that number, then you must toss out life being irrepressible and/or evolution being inexorable. (Modus tollens again.)

TT: I think the assumption that life should be common in the galaxy is a reasonable one, and the presumption that it is not common is an unreasonable one. I don't have specific calculations to back this up, and neither does anyone else. However, everything we know about life on earth is common. Hydrogen, Carbon, Oxygen, Nitrogen, all key elements to the life process are also the most common elements in the universe. They are ubiquitous, and are thoroughly spread out all over the interstellar medium, and everywhere we think stars and planets are likely to form. If the advent of life is a natural process, then it should be common.

DS2: And even if life only ever advances just to our stage - and is there any reason to believe we represent the limit? - we should hear from some of these billions of civilizations.

TT: The one and only argument you have presented is "they are not here so they do not exist", which has nothing to do with probability and statistics, and everything too do with a biased interpretation of same.

DS2: "They are not here so they do not exist" doesn't do justice to my argument, which I don't think can be safely condensed any further than "my argument in a nutshell" at the top. Notice that it allows for the possibility of "They exist, but humans are special, behaviorwise."

DS1 [continuation of the original letter to the editor]: Let me try to guess why those who are supposedly qualified to explain the matter to us have missed the boat so badly. It seems we have difficulty seeing beyond the way things are for us. We're just taking our first steps, so other alien civilizations probably are too, right?

When there are potentially billions of them, and they've had billions of years to beat us to the punch? No way.

(Jump forward to the next chunk of this letter, or back to the beginning of it?)

TO: Your argument is based largely on assumptions that since aliens have not contacted us, they don't exist, which is horribly unscientific.

DS2: That is an inaccurate simplification. Since aliens have not contacted us, we must conclude any of several scenarios: 1) that no alien species exist; or, 2) if they do exist, none have reached our technological level; or, 3) if some have reached or surpassed our technological level, they must be either very rare; or 4) if they are not rare, they have reasons for intentionally avoiding contact. That covers it. No matter which of those cases hold, the unavoidable conclusion is that humans are special, either numberwise or behaviorwise.

DS1 [continuation of the original letter to the editor]: More fundamentally, the problem is one of grasping huge numbers. The immensity of a 100 billion is outside of human experience. We are used to repeated addition, but not repeated multiplication. We imprecisely think of a million as a few thousands lumped together, and a billion as a few millions lumped together. After all, it's only a few extra zeros tacked on the end. So, a few thousand, a few billion - what's the difference?

If there were only a million stars in the galaxy, our uniqueness would be astounding enough. But 100 billion is so huge that even if we were in regular communication and commerce with "only" a thousand alien civilizations, trying to fathom our inclusion in such an exclusive group would still cause mental distress. Perhaps it is a merciful thing that we can't conceive of a 100 billion.

(Jump forward to the next chunk of this letter, or back to the beginning of it?)

DS2: Let me make the preceding point even more forceful. It was written based on a notion that these hypothetical "thousand alien civilizations" all developed completely independently from each other. But how likely is that?

You'll have noticed that I generally reject the anthropomorphic analogies such as "hey, humans are gonna blow themselves up, so alien civilizations will too." In this case, though, I see a compelling analogy.

On earth, all it takes is for one society to develop something, and it spreads quickly to virtually all other societies - friend and foe, technologically advanced or backwards. Printing, cars, airplanes, radios, computers... you name it. Is there any reason to think the same forces wouldn't be at work when some alien civilization develops advanced means of communication and space travel? All it should take is for it to happen once (or a few times, what the heck) and it would spread like wildfire to civilizations around the galaxy (of whom we've heard from none.)

Anyhow, if an alien spaceship lands in my backyard tomorrow, not only will I be compelled to ask, "What took you so long?", but I'll also need to know, "Where are all your buddies?" I'm not saying there are no possible answers to those questions, just that whatever answer they give cannot be anything expected based on current "party line" scientific thought.

They might say, "We scouted out 70 billion solar systems on the way here and:

"yours is the first to have conditions similar enough to ours to support any life whatsoever."

"they all had life, but evolution stopped at apes on every one."

"they all had advanced civilizations, but warned us, 'Don't go near Sol! Please don't even let any of your electromagnetic waves leak in their direction!'"

"HAHAHAHA... You thought all those specks of light were all (heeheehee) stars! (guuurrk!) Hoo boy, that's rich!!! HAHAHAAAAAAAAAAAAA!!"

I promise to post their answers to talk.origins.

DS1 [continuation of the original letter to the editor]: Many scientists are skeptical the evidence from the meteorite indicates Martian life. (I personally wouldn't be surprised if the rock had been kicked off the Earth a while back.) If they are right, we are back to square one. You can return to believing that life exists only on Earth, or that life is rampant throughout the universe, or anything in between.

Where you don't have a choice is in regards to the specialness of humans. If there are others out there, it is inconceivable - literally - that in billions of years nobody has left any sort of sign.

(Jump forward to the next chunk of this letter, or back to the beginning of it?)

TO: Once again, you are ASSUMING things. You assume that the aliens would have advanced much farther technologically than we have. By your assumption, an alien race could say human beings don't exist, since we have not visited them in the last billion years.

DS2: Yes, I am assuming that since we have only been technological for a few decades, most of the billions of advanced alien civilizations will be much farther along than us.

No, my argument is not based on our not having been contacted by a particular civilization, such as one from Alpha Centauri; rather it is based on the lack of contact from anybody in the galaxy.

TT: The only assertion that you can make is that we have seen no unambiguous sign of extraterrestrial life or technology. However, since we have been able to detect such signs for hardly a few decades, you certainly cannot insist that no such sign existed during the time we were not looking! It would, for instance, have been very easy for some alien prospecting mission to come here, look at the earth, and leave bored stiff, even as recently as 100 years ago, without our ever knowing they came and went.

DS2: Surely you know how far-fetched that last assertion is. But I'll play along. You know what's coming. If, of the billions of advanced alien civilizations, we are the only ones who do not clean up our space exploration junk behind us - which we don't - then that makes humans special (in maybe a dubious sort of way.)

DS1 [completion of the original letter to the editor]: We humans became technological only a few decades ago and already we're making our marks.

(Jump back to the beginning of this letter?)

TT: You write as if you are sure that there cannot be anything alive out there besides us, but your only justification for saying it is that "they" aren't beating down our doors to get in.

I don't buy it. Aside from the obvious problems involved in trying to psychoanalyze some totally alien intelligence, consider this: in all of the billions of years evolution has had to clunk away here, on the earth, we are the most technological species that has come along. Yet, with a minor modification or two in our natural history, humans might never have gone the technological way they have. Indeed, it seems to me (not intending ethnocentricity) that without the heavy impetus from Europe, the world even today, would be much more agrarian and rural than it is. It is not at all clear to me that the development of technology is a necessary side-effect of the evolution of life. Why should every planet that develops life automatically develop technology?

DS2: It sure sounds to me like you are arguing that the human race may be extraordinarily special, behavior-wise - if not downright unique. I thought that was my side.

And again, I must point out that you are fixated on one alien intelligence when there should be billions to psychoanalyze. Can we be different from all of them?

TT: And if they do develop technology, why do they all have to act and think exactly the same way we do?

DS2: My argument is not based on any - and certainly not all - alien civilizations acting and thinking "exactly" like us; just that some of them develop radio communication and/or space travel. If none of them have, then that makes humans special.

TT: I stand the same ground I did when I was a SETI-person. There are no valid a priori arguments to support the conclusion that there are no equal or superior technological civilizations out there. The only way you/we can ever know the answer is to look and see what's there. One sure way to never discover anything is to never look for anything.

DS2: Please, continue to look. When we find them - or they find us - is when the fun begins. If they don't have some good answers to my two questions, "What took you so long?" and "Where's your buddies?", it's straight to the loony bin for me.


General comments

These comments weren't directed at specific statements in my argument.

TO: If you want to make a claim about the Earth being special, you should define special in some meaningful manner. I think the Earth is special since it seems to be the only planet I live on. Makes it special to me. Did you have another meaning?

DS2: You missed my point, but I'll be glad to respond. I don't believe for a moment the earth is special. I believe that almost all stars will have an orbiting body - maybe several, maybe many - which have earthlike conditions. If our own sun were a thousand times brighter, it just means one (or more) of the planets and moons further out would be candidates for hosting life.

TO: Think about it in terms of lotto odds. The chance of your number hitting the $15 million is everyone else's number against yours, could be 5,000,000 to one. The chance of the pot being won is considerably greater - usually once every three or four drawings.

So... the chance of humans making it to the top is about 1 divided by the number of all the other species. The chance of anything at all becoming king of the hill is guaranteed.

Sorry. Reality is a bore, face it. Humans special? Only in a believer's mind's eye.

DS2: You're saying that even if humans are the "king of the hill", you refuse to recognize that as special. I'm sure that's an extremely narrowly held opinion. After all, we do make a big deal out of the $15,000,000 jackpot winner, or the guy who hits a hundred home runs in a row, or the golfer who shoots an 18. Yes, you might hear a lone, wet-blanket voice saying, "Look, statistically it was bound to happen!" Meanwhile, the rest of the world is going bonkers.

TO: Why is being "special" so important?

DS: The human race being "special" is not important to me. If there are aliens out there who can think circles around us - more power to 'em. (I just wish they'd send me a message!)

I believe the question of whether or not we are special is important scientifically - insofar as anything we wonder about is "important".

TO: Whether something is "special" or not, by your definition, depends entirely on the particular views of the beholder. Your definition is too flexible. It allows you to win any argument of "specialness" because you can move the goalposts at will.

DS: What I mean by special has to do with superior intelligence, control over the environment, position in the food chain, technological advancement and such. Luckily, no pestiferous soul tried to sabotage the discussion with the stance, "Who's to say humans are even more special than honey bees???" Semantics is always a problem, but I think we're all more or less on the same wavelength here.

Supposing that every single star in the galaxy had a planet with a species so close to humans that we could interbreed, I assure you I'm not going to compare average heights, or naming conventions, or freckle disposition, or number of law students in order to declare us special. I would compare our communication and transportation technology with theirs.

However, looking back over the discussion, I can see where you're coming from. Someone says, "Well, if none of the alien civilizations were this, or do that, then we wouldn't know about them." I come back with, "But humans are this, or do do that, so that makes us special."

The problem is, many of the rebuttals were almost nonsensical, so my responses look nonsensical. Participants proposed that the other alien civilizations all became energy blobs; that they all communicate with some unknown form of radiation that is non-electromagnetic; that they have all conspired to keep their existence unknown to us; that they all lost interest in searching for alien life after one half-hearted attempt; or that they all moved somewhere shielded from us.

Perhaps it would have been better for me to say, "Don't be ridiculous" rather than letting myself get dragged into responding to these infinitesimal possibilities.

TO: I looked at your page. You still have trouble considering numbers between 1 and billions.

DS2: If scientists want to change their tune and put forth that the formation of life is, well, ummm, er, not so easy after all, we can start talking in terms of millions, thousands, hundreds or dozens. Likewise with evolutionists regarding the appearance of creatures that have some control over their environment. (Current popular thinking has it that humans were as certain as a drunk falling in a ditch!)

But if and when that time comes, the problem is the same: where are the millions or thousands? Frank Drake's current best estimate is that there are somewhere between one thousand and one hundred million advanced extraterrestrial civilizations in the Milky Way. The big number would place them cheek by jowl - 10 light years apart. The small number places them a not-overwhelming 3000 light-years apart. (Why wouldn't many of these 1000 civilizations be millions of years old?)

What about a hundred civilizations not significantly more advanced than us spread among the 100 billion stars? If that were the case, it's very elite company - and you're still left with the problem of explaining how our current level of technology represents the universal limit.

What about a dozen? End of discussion!


SETI - The search for extraterrestrial intelligence

TO: The SETI program, Earth's only real attempt to locate alien civilizations, has not even come close to a comprehensive search of the electromagnetic spectrum for intelligent signals - just one small band in a certain favourable region of the spectrum. This is like a drunk who searches for his keys beneath the streetlight because he can't see anywhere else. It's definitely not an all sky survey either.

TT: The NASA All Sky Survey proposed to avoid the "searching under the lamppost" problem, by searching the entire sky, and the entire spectrum between 1 and 10 GHz, the window being set by Galactic interference below 1 GHz, and the atmosphere above 10GHz. The targeted survey would detect much fainter signals, but would concentrate on "likely" stars. The 305-meter primary at Arecibo is capable of detecting "itself" (i.e., an equivalent instrument) anywhere in the Milky Way Galaxy [subject to the obvious constraint of signal travel time]. Congress de-funded all NASA programs related to SETI in 1993.

DS: Here is how Frank Drake described the NASA SETI project from his book's 1991/1992 time frame. It sounded very impressive. How far did it get before defunding?

Drake says NASA SETI will run for years. It uses at least 5 telescopes. It constitutes the largest single program running at Arecibo. There is a fully dedicated telescope at Green Bank. It employs more than 100 people. It searches 1000 nearby stars. It also does an all-sky survey. It searches with 28 million channels. It incorporates sophisticated software that looks for intelligent patterns. Three days of operation accomplishes more than everything done in the previous 3 decades. It takes only one 1/100 of a second to duplicate Drake's first 200 hour search in 1960. (Return from jump to footnote.)


The Fermi Paradox

Here is an interesting look at earlier attempts to wrestle with my question.

TT: Your argument is in fact so common that it has a name, "the Fermi Paradox". It is a valid question, but its answer is far from being as obvious as you think. Nevertheless, Frank Tipler (author of the Anthropic Principle) espouses essentially the same position as you have here, and so have at least a few of the radio astronomers here at JPL that I have worked with.

DS: Darn, I wanted credit. Seriously, I have to scratch my head at the fervor with which talk.origins attacked my argument when it turns out it has a long and respected history, put forth by "name" scientists, even.

TT submits an extract from the article "Tsiolkovsky, Russian cosmism and extraterrestrial intelligence" from the QUARTERLY JOURNAL OF THE ROYAL ASTRONOMICAL SOCIETY v36(4): 369-376, (1995 Dec):

Although Konstantin Tsiolkovsky's (1857-1935) contributions as a pioneering theorist of spaceflight are well known, his equally original thinking about extraterrestrial intelligence (ETI) is only now coming to be fully appreciated as the philosophical works he wrote late in life have become available for study.

[T]siolkovsky held that ETI was prevalent and that advanced life forms would become spacefaring and spread beyond their natal star systems. This led him to anticipate the Fermi Paradox and offer his own solution to why we have not seen any signs of advanced, spacefaring ETI. According to Tsiolkovsky, although such ETI could long ago have visited Earth and then uplifted us to their own level of development, we have been spared intervention in the hope that humans might develop a uniquely 'new and wonderful stream of life' to add to galactic civilization.

DS: Pretty far-fetched, Konnie. Would each of the billions of advanced alien civilizations be so careful? Clearly, humans aren't.

TT submits an extract from the article "Machine intelligence, the cost of interstellar travel and Fermi Paradox" from the QUARTERLY JOURNAL OF THE ROYAL ASTRONOMICAL SOCIETY v35(2): 157-175 (1994 Jun):

If machine intelligence is possible, and the computers on which it is based resemble today's computers in some very fundamental aspects, then interstellar travel can be accomplished by data exchange as opposed to the physical movement of matter. Assuming data exchange by radio, such travel is many orders of magnitude cheaper than physical travel.

This low cost provides a huge incentive for an emerging society to join an existing galactic civilization as opposed to physically colonizing the galaxy. It is likely, therefore, that there is at most one advanced civilization per galaxy. This civilization may well have unified goals and objectives, thus removing the strongest underpinning of Fermi's paradox.

DS: Huh? Somehow the fact that all advanced civilizations eventually "join the club" explains how we can never make contact with them???

TT submits an extract from the article "The Moon and SETI" from ACTA ASTRONAUTICA v26(3-4): 151-155 (1992 Mar-Apr):

Many studies lead to the expectation that millions of planets in the galaxy are suitable for life. Studies of interstellar travel and migration show that the entire galaxy could be colonized in a few million years. Our 4-billion-year old solar system should have been colonized by other civilizations by now. This leads to Fermi's Paradox: where are the extraterrestrials?

To answer that question, this paper focuses on the obvious but often overlooked observation that the Earth and the Moon constitute a unique "double planet." Some evidence suggests that the moon was captured early in the history of the solar nebula and profoundly affected Earth's evolution.

The Earth may have ended as a frozen, one-plate Mars or a runaway-greenhouse Venus if it had not enjoyed the presence of the Moon. Because of the expected rarity of double planets, we may be alone in our galaxy, and the search for extraterrestrial intelligence (SETI) may be more successful in nearby galaxies than in the Milky Way.

DS: Come on, now. We have a hard enough time finding planets in our own solar system without moons. To suggest that our moon is not only out of the ordinary, but downright unique...??? What can ya say.

In any case, if and when someone does put forth a good, solid, logical, plausible, irrefutable explanation why life can exist only on Earth, that makes us special. Got it yet?


I try not to overdo levels in my website, but you can jump to my page devoted to the Fermi Paradox now. It takes a look at the question as dealt with in a batch of books found at the library - as opposed to the obscure scientific journals quoted above.

 


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