Pictures on the Wall Reconsidered

When decorating a home, it is customary to put things on the walls. Large expanses of bare wall are unusual. Visitors will note the blank space as a peculiarity.

For the past year and a half I have lived in an apartment with a rather eccentric and demanding landlord, who asserts that any screw holes or nail holes must be patched up perfectly to avoid a charge against the security deposit. My solution has been to just leave the walls bare. For the five years before that, I lived in a converted attic with slanting walls which do not allow putting up pictures in the usual manner. I elected to leave the very few suitable vertical wall spaces bare as well. Although external factors led me to this situation, I find I like this arrangement.

I am of the opinion that thoughts should be guided from within. We should choose what to think about. Of course this is usually originates with our senses. Whether we use old-style books or magazines, or look at screens, we usually start with words and images to guide our thoughts. (The battle over advertising's imperative to impose their own agenda on our minds is the topic for a different day.) In the internet era it is more and more possible to actively choose. A TV channel was much more passive. The only options were to look for a new channel or turn it off. Even there, the TV screen was constantly changing, showing us new things. Today, clicking different places on a screen in sequence can lead to a stunning variety of different destinations.

Pictures on the wall never change. When we look at them they interrupt anything else we were thinking about and our perceptions of them take a place in our minds. Is there really anything that we want to endow with that power? Is even a picture of a beloved deceased parent really helpful? Perhaps you do want to remember them, but do you want your memories to be guided by looking at that particular patch of wall at that particular time? Most pictures do not tie us to something of such powerful emotional significance. Why should we think about that particular thing (yet once more) when we were in the midst of a train of thought we recently chose to start in on? The mind wanders plenty as it is, but do we really want to give another nudge to the wandering? We may feel we get so used to what's on the wall that we don't really register it any more. But more of our thoughts are governed by automatic processing than we are aware of. And if we really don't see it, there's surely no strong reason for it to be there.

Then there are visitors. What a first-time visitor sees when looking at our walls gives them an impression of us. But does a series of pictures, however carefully chosen, really convey what we want to convey? If we follow the standard rule that walls should be covered with things, then they can judge us compared to the other things we might have chosen to cover our walls with. But perhaps we would do better to escape that paradigm entirely, and with mind uninterrupted by anything on the walls, hope they listen more carefully to what we say, or think more carefully about what they say to us. If we want them to concentrate on a particular set of images, we can show them a photo album in some format or other (phone, tablet, paper book).

I recently saw at someone's home a sort of intermediate arrangement, which is presumably quite common. A large-screen TV had a looping slide show of pictures from a recent vacation. Presumably they enjoyed being reminded of that vacation. But they quite likely replaced it with a different set of pictures after the next vacation, or perhaps simply shut it off and had a blank large-screen TV on that section of wall.

Compare this to places outside your home. If you have your own office, the same considerations would apply, if to a lesser extent. If you go into a restaurant, the décor has likely been chosen to help set a particular mood, and quite possibly you chose the restaurant in part because of the "ambiance" for that particular block of time while you're eating. If you go into something like a Target or Walmart, you have put yourself in the world of retail commerce and probably aren't upset to be inundated with advertising -- some of it might actually be useful! If you go into the sanctuary of my Unitarian-Universalist church, you are typically wanting to nudge your thoughts in the direction of the profound or spiritual. Stained glass windows are in line with what you want to be thinking about.

In your own home, whatever is on your walls is bound to be relevant to a much smaller fraction of the things you want to be thinking about at any given time. Likely so small that they hinder rather than help you in your life goals. Maybe bare walls would serve you better.

It's not the money, it's the eternal emails

I am a fan of the YouTube channel "Mentour Pilot" https://www.youtube.com/@MentourPilot, especially the series on airline crashes or near-crashes. I'm not sure why, but I like them. The Swedish owner "Petter" has a variety of sponsors. One sounds kind of appealing to me, "Curiosity Stream", which would offer a wide variety of documentaries. What amuses me is how he emphasizes how it's only $20 a year, and you can get $5 off if they use his code, and to top it all off there's a money-back guarantee (I'm making up the specifics, but you get the idea). Presumably others with sponsors make the same sort of pitch.

But the price has nothing to do with why I won't subscribe. I'd happily pay twice that much. I won't subscribe because once I did, and my information got into their database, my expectation is that I would never, ever be able to free myself of the various promotions and "junk email" arising from that purchase. Possibly if you look carefully there's a way to opt out of them selling your information to others, but it wouldn't stop they themselves from sending me promotional email forever. Or they would change their terms of service, or Curiosity Stream would be bought by a bigger organization who would inherit the access to your information, and send you promotions for far more products. Basically, my perception is that one way or the other they've got you. Perhaps writing a blog post with "Curiosity Stream" in it will bring me to their attention and get me on their lists.

You could create an identity with links to entities you're not sure you want to hear from forever and then shed it every so often, like Thidwick the Big-Hearted Moose shed his antlers. Perhaps some service could help you with this. But perhaps the marketers have a clever way of rediscovering people if the new identity subscribes to some of the same things as the old one.

If there was a service that guaranteed they would use your identity for the sole purpose of the subscription you make, and never ever send you another email or share your information, on pain of criminal penalties vigorously enforced, I think they might have a market -- if we could ever really trust them.

I'll also share one way I stayed naive until just a few years ago. When you belong to something like the ACLU, they send messages like, "your membership is about to expire!" and "last chance!" and I somehow got the idea that if I didn't respond then I'd lose my chance to be a member and they'd take me off their mailing list. Ha! Of course they won't ever take me off because they'll always be hoping I'd come back and give them more money. (The ACLU has lost its way -- they have become "woke" at the expense of protecting civil liberties.)

Subscriptions and "Ghosting"

I recently emailed an old work colleague to reminisce about that old job, and he replied telling me he was not on speaking terms with me because of a blog post I had made a year and a half before. He had disliked it, but decided that we were so far apart there was no point discussing it, so he just unsubscribed from my blog. This overall situation has disturbed me quite a bit.

I think in modern terminology what he did is called "ghosting" -- someone just disappears without a trace, and you aren't informed of it.

I don't know how many people read my blog. When I looked using the simple tools at hand, I found one person subscribed by the simple method, but I know from email replies that there are at least 4 other people who have read my blog within the past year. At least two of them get my blog posts by email, one of them (maybe more) from Google FeedBurner. I have generally been fine with that situation. I figured only a handful of people read the blog, and I was writing for those few. I started this blog in 2007, which is forever ago in internet time, and I am very poor at figuring out how these shifting program configurations connect things together. There was some hint that FeedBurner was itself an obsolete technology. If anyone knows how to figure out who is actually reading my blog, I'd love to know. Then I'll at least have a method to figure out if someone "ghosts" me.

The readers I have heard from emphasize that they don't always agree with everything I say (possible translation: think lots of it is really crazy), but find it interesting. A blog author would ideally get comments from readers and there would be occasional discussions back and forth. I've accepted that my blog isn't that kind of place -- which is probably more the rule than the exception for blogs with few subscribers. Sometimes I toss out ideas that I am not at all sure of, and a few words might lead me to look at it again and happily say (perhaps even with relief) that I take it back.

The post my former colleague reacted to so strongly was one where I said people were eager to make sure Derek Chauvin paid for what he did without knowing the full evidence, and I gave some reasons why maybe he wasn't really guilty of murder. Simply being alerted that "Someone really hated this post" led me to look at it again and see that it was terrible. I hadn't looked at even the basics of evidence on the other side, and it quickly became apparent to me that he was appropriately convicted. The whole post also had an emotional tone to it, where feelings were trumping careful thought. I first quickly posted a reply saying that this was a bad post and I didn't believe it, and then within a couple days decided it was such a bad post I would just delete the whole thing (I do have a saved copy in case anyone really, really wants to see it).

My former colleague was an "inconsistent ghoster", where my recent email brought the whole issue to his attention again, but I can hardly blame him for that. It just happened to bring to light a situation that otherwise would have just lain hidden.

Overall I think what's disturbing is this idea that people who sign up for the blog might have extremely strong negative reactions -- and I'll never have a clue. Of course maybe many or most of my readers are prepared to have very strong negative reactions but just let them go by and wait for the next interesting idea. Perhaps they would think that only if I was actively a purveyor of evil would they be moved to reply or unsubscribe -- but I would never know about the latter course either. If anyone wants to comment to me privately, my email is bart.wright@comcast.net.

In one post from a while back (http://bartfusn.blogspot.com/2021/05/racism-as-one-of-many-comparable.html), my reasoning led me to the astonishing conclusion that racism shouldn't be in the top tier of problems we should be working on. I also said I definitely believed it was a serious injustice -- not trying to say there was no racism or white people have it just as bad or anything of that kind. I'm not sure I had ever heard anyone with that combination of views. Could some reader with a few words point me to some article that would explain why my thinking on the subject was wrong? Or maybe they all agreed, or they just let it go -- reading a blog doesn't commit anyone to provide feedback, ever. I guess I'll never know.

Older Men and Younger Women

It is generally assumed that men and women will choose partners of roughly the same age, and the vast majority do. They share life experience and outlook in a way they would not with much older or younger partners. Shared experience and outlook are ingredients in helping to make a rich emotional relationship.

Yet fairly often older men - even up into their 60s or beyond -- pursue women in their 20s, and sometimes marry them. Sometimes it is these younger women who are pursuing the older men.

In my part of the world the accepted explanation is what I would call the feminist take: the men are denying their mortality and want to feel younger. They want a woman they can more easily manipulate, due to her inexperience. The woman they seek might be called a trophy wife. As for the women who accept the courtship by the older men, they will be called gold-diggers, or women who want a daddy figure.

There may be some grains of truth to these explanations, but there is something more profound going on, something that goes back to human mating patterns in our environment of evolutionary adaptation (EEA, a key concept in evolutionary biology). Evolution strongly favors leaving more descendants than fewer. Women over 45 rarely bear children, while women who are 20 or 30 very often do. So it is a simple and powerful evolutionary force that would tend to make men attracted to these younger women more intensely than older women. In our society, we see this played out in men whose marriages end (due to widowhood, or divorce initiated by either party) and marry younger women. In many other societies polygamy is practiced, and there the men don't need to divorce their older wife(s), they just add on the younger one -- or more than one. In some of these older societies women do not have choice as to whom they marry, and some might be very upset to be stuck with an older man -- but quite possibly not all.

Some young women today who have undeniable freedom of choice do freely choose an older man. Why would they do that? There is an evolutionary explanation for that preference as well. Evolution programs women to seek two things in mates. First, like all mammals and a great many other creatures, the females seek males with the best genes. Presumably those genes will make the offspring more successful at reproducing, and the women's genes that are along for the ride will also spread more widely. Second, humans have a rare pattern compared to other mammals -- males actively help to provide resources for their offspring. So when choosing a mate, women will prefer males who seem better able to do that. In our terms, that could be summarized as "richer". A woman may well prefer a successful young man to one who seems unable to keep a steady job. All else being equal, she would prefer a younger man to an older one. But how to trade off these two desires? It is quite common that a relatively rich older man can be expected to provide more resources to his children with his second wife than a poor young man could to those with his one and only wife. The quality of genes does not vary significantly over lifespan. So even if a man is physically past his prime, his genes will tend to produce young men who are like he was as a young man -- not as the older man he is when he (re)marries.. However desirable they once were, women of 45 rarely produce any children, while men of 60 usually can father children quite reliably.

Evolutionary explanations are very often not expressed directly. Instead, they mold our desires in a way that meets the ends of evolution without our conscious choice. A very clear case is sex and contraception. If we were guided only by a conscious desire to produce offspring, we wouldn't bother with sex if we weren't planning to reproduce, and there would be no need for contraception. But evolution has not endowed us with a desire to produce offspring, it has given us a very strong desire to have sex. This accomplished the goal very well, in the original environment where there was no contraception. So we still strongly desire sex. Knowing intellectually that it cannot produce offspring in most cases barely attenuates this desire at all, and we are not embarrassed to seek out contraception and still want sex very much.

Return now to marriage. In many societies, marriage is an economic contract, with no pretense at romance. The two partners have sex, but otherwise their lives are lived in quite separate men's worlds and women's worlds, but each helps in their own sphere to raise the children. But in our society -- and a great many others -- men and women feel a strong desire for each other and often feel love. This helps them stay together in the face of adversity and jointly raise their children and also induces them to conceive more children. But the subjective experience is love -- a very powerful feeling.

The same thing is likely to happen between older men and younger women. They love each other. Evolutionary explanations like wanting to father more children or wanting more resources for children are typically not experienced psychologically. The young woman and the older man genuinely love each other! The feminist story devalues such feelings as shallow illusions, and they claim any actual examples are quite rare.

We have no right to discount a young woman's desire for an older man because it might stem in part from his success in life. Her yearning for him must be respected on its own terms, as is any other romantic yearning. And I assert that we also have no right to discount an older man's yearning for a younger woman. When such yearnings are reciprocated, the result is a love as real as any other.

In my experience, it is older women who judge such situations most harshly. They will give young women a pass on the theory that they are inexperienced and misguided, but the men will get nothing but hostility. A man's desire for a younger woman is attacked, even if he is single and there is no question of deserting an older women. If his desire is not reciprocated, he is in for even harsher treatment. What on earth made him think an attractive young woman would go for *him*?! This entire attitude is demeaning and disrespectful.

It might also be selfish. Older women -- which here might mean age 40 and up -- want male partners as much as younger women -- this desire does not disappear when their fertility drops, though it may become noticeably less. The men who are pursuing younger women are not available to them. Older women may not at all like the idea that younger women are in an important sense viewed by men as more valuable than they are. They also might realize that their condition of being without a partner is partly their fault. When they were young and more desirable, they were perhaps more choosy about a mate than they would have been in retrospect, or busy with careers that might not really have been worth it, if the consequence is to live the rest of their lives single and childless. This surely does not apply to all women or even most women.

But kind-hearted people are sympathetic when anyone develops romantic interest in someone their own age and it is rejected. They don't look hard for reasons why it wasn't a genuine interest. They should be just as sympathetic if an older man develops romantic interest in a young woman.

I speak from the perspective of a coastal, blue-state, leftist culture. There are a lot of women who might have a different view. Donald Trump felt confident that women liked it when he grabbed their pussies, and bragged that he did so frequently. This was not enough to keep a majority of white women from voting for him. This certainly opens up the possibility that such women do not hew to the feminist stance on other sex- and gender-related subjects too. This might include older men with younger women, and some may have what I would consider a more realistic attitude. But this is just speculation.

I am now a single man in his late 60s. I am myself aware of an emotional and sexual interest in young women. I would like to be able to tell others, including casual acquaintances, about crushes and feel confident they would respect that feeling. They are most welcome to point out practical difficulties to any relationships that might emerge from such feelings, and in fact I heartily agreed and typically regard them as insurmountable. But that does not invalidate the initial attraction.

Cognitive/Memory Limitations

 I've been worried about some aspects of my memory for some time. Twelve years ago I went to a job interview in Kendall Square, and when I was done I went to retrieve my car from the parking garage and could not find it. I was in the wrong garage, and they were also quite different -- one had three "aisles" per level instead of the usual two. But "wrong garage" didn't occur to me until I had spent half an hour or more scouring the one where I thought it was. I also thought I had short-term memory problems, like being far less able than I thought was normal to (say) be given a list of 10 words and then say them back, especially the version where they distract you with something else in the middle. I got a cognitive assessment and was assured everything was fine, though there was no test relevant to the "wrong garage" problem, I don't think.

What seems to happen more lately is to have a conversation with someone (this is on the web), and then forget two weeks later that it ever happened; often it never occurs to me to wonder if I've had the conversation before. I now try to adjust a bit by assuming I might have had just about any conversation earlier, and the web (at least the programs I use) remembers history, so I can check. But it does get in the way of even tentative friendships when I see someone's name come up and have no memory of whether I've talked with them before and if so what was said, and what it revealed about who they are.

You have heard of "test anxiety" or "performance anxiety" (of various kinds). We've all heard of word-finding difficulty, a symptom of aging. But what I experience sometimes is "word-retrieval anxiety". For instance, "What's the name of the kid in that family, the middle child? <oh no, I'm not going to be able to remember it.!..> And indeed, I can't remember it. I remember the name of the older brother and younger sister, just fine, even if it's the middle child who was my friend, because those aren't the ones I was trying to remember. My few simple attempts to find any discussion by people with this sort of problem on the web were not successful. I think it may be getting worse as I get older, but I'm not positive.

Since late high school almost everything I write has been composed at a keyboard. Along with getting a high typing speed (100wpm or more, which I still have), I also had good accuracy. I typed the words I meant to type, exactly right. This was a handy skill for a software engineer, where quite often the computer is intolerant of errors of a single character, and if you don't make them you don't waste time trying to find them or fixing them.

Then a decade or so ago errors started getting more common in my writing. I would put in the wrong homophone, I would reverse letters, or drop a letter. Lately these get more common, and with surprising frequency I just omit a word entirely. One source of evidence of this has been what the spellchecker finds -- when I run it in "batch mode" rather than interactively, it's easy to get an overall picture.

I still write some computer programs, and now I get the series of compiler errors indicating this exact problem -- I skipped a character here, put the wrong one there, etc. At least as of last year, I could solve most of the programming problems in "Advent of Code", which often require some pretty clever computer programming. Lately I wrote a program (a solver for "Waffle" is the most recent, I think) where I had to correct 15 or so typos, and after that was done the 200-line program worked perfectly the first time -- the logic was correct.

One sort of cognitive decline I had never considered in advance was losing my knowledge of spelling. I don't mean the general rules of spelling, but the exceptions that we learn that go with individual words. One example is "Cacophony". I was writing this in some document, and "cacaphony" is what came to mind. The spell-checker flagged it immediately, and whereas in the past after making such a rare mistake I would have instantly known the real answer was "cacophony", now I don't. I just look at the word and wonder how to spell it, then have to look it up -- entering the wrong spelling as a search term in Google will usually find the right one. "Guerrilla" -- Two r's or one? Two l's or one?

For Wordle I wrote a trivial little program that lets me enter a word and simply asks, "Is this in the Wordle dictionary of valid answers?" (While the program will reject many rare words immediately so you don't lose a guess, it will accept 10,000 or so words as guesses compared to 2,000 or so valid answers.) I figure use of this program is completely defensible and not cheating, because the list of valid Wordle answers is in no way systematic. For instance, plurals of common words are often omitted, such as "stars" and "roses". But in some cases I use it to ask, "Do I have the right spelling of this word, or not?"

My cognitive decline is highly selective. Along with the computer programs, I win at least 99% of my games of Wordle, Quordle, Octordle, and Waffle. And I think/hope people can read my posts here and find the text to be well-written and the ideas expressed well.

I was going to write about some other memory problems I have -- but I can't remember them, now.

Did I already write a blog post on this issue? Checking reveals that it wasn't recent if I did.

Why aliens exist but aren't here: the simplest explanation

I suppose I am not the typical blogger when I say, "I covered that topic 14 years ago, so I don't need to cover it again, right?"

Recently the question of the existence of alien intelligence has come to my attention again. It's a sensational topic. People have been discussing it continuously, I'm sure, but it comes to me anew as part of my scanning for suitable YouTube videos to watch.

These are the links to the posts I made 14 years ago:

http://bartfusn.blogspot.com/2008/06/aliens-are-bountiful-but-unreachable.html

http://bartfusn.blogspot.com/2008/09/failure-to-detect-aliens-does-not-mean.html

None of my views have changed, but I will add a new analysis. Some people may find it boring. (Oh, no! I will lose viewers and advertising revenue!)

Wikipedia includes an article on "The Fermi Paradox", which is essentially: If earth isn't special in some way, there should be lots of other intelligent civilizations in the galaxy. Yet, we have not detected any, let alone had any of them come visit us. How can this be?

First I'll give my answer, which is basically: "You can't get there from here." Most likely the resources and technology needed to colonize a single other world are too great and beyond the capabilities of EVERY ONE of the millions of civilizations.

But if we get past that step, we realize that colonizing the galaxy requires an expanding population growth of colonized planets. Some of the time a colonized planet has to colonize two or more others. If civilizations can expand at most for a small distance around their origins, and habitable planets are as sparse as we suspect, that is why we haven't met any aliens. I'll abbreviate "You can't get there from here" with the shorter "TOO FAR".

I think all of the other explanations are unsatisfactory (except for the Zoo Hypothesis). Here I focus on the Wikipedia article's list of hypothetical explanations.

https://en.wikipedia.org/wiki/Fermi_paradox#Hypothetical_explanations_for_the_paradox

Earth is special: extraterrestrial intelligence is rare or nonexistent. This is hubris. As scientists look, they find planets around stars, stars of the right types, and planets of the right size and composition, the right distance from their stars. Given our current detection capabilities, everything they would expect to find in support of life elsewhere they have found.

The key question for the others is not, "Is this a possibility?"or "Is this pretty likely?" but rather, "Is this so certain that it would prevent ALL of the millions of civilizations from reaching us?" Some of them are about time limits on these other civilizations. Others are about their being too alien. Others are about why they don't communicate with us. But all are consistent with the resolution of the paradox being that there are alien civilizations (likely millions), but we haven't detected any of them.

A. Global catastrophic risk. ALL?

B. Intelligent alien species have not developed advanced technologies. TOO FAR. If millions of species have been at this for a long time and none has developed the right technologies, chances become very high that there is some limitation beyond cleverness, that is a barrier to all societies. ALL? and TOO FAR mix.

(I switch here from using letters for possibilities to numbers).

As an overall concept (specific examples below) some complex set of psychological or sociological forces will limit or destroy civilizations. None of these have the aura of inevitability. ALL?

1. It is in the nature of intelligent life to destroy itself. ALL?

2. It is in the nature of intelligent life to destroy others. ALL?

3. Civilizations only broadcast detectable signals for a brief period of time. ALL?

4. Alien life may be too alien. (This becomes a version of "earth is special", if ALL of the millions of species are so terribly alien. The electromagnetic spectrum and the presence of physical bodies seem pretty basic). ALL?

5. Colonization is not the cosmic norm. ALL?

6. Alien species may have only settled part of the galaxy. TOO FAR. With so many species having the opportunity for so long, why would they stop halfway?

7. Alien species may not live on planets. ALL? RELEVANT?

8. Alien species may isolate themselves from the outside world. ALL?

9. Lack of resources needed to physically spread throughout the galaxy. TOO FAR. Some few individual planets may be brimming with resources, but that's just one small step on being able to spread.

10. It is cheaper to transfer information than explore physically. IRRELEVANT, or a variant of "too alien".

11. Humans have not listened properly. IRRELEVANT.

12. Humans have not listened long enough. IRRELEVANT.

13. Intelligent life may be too far away. TOO FAR. Treated more fully in other points.

14. Intelligence may exist hidden from view. IRRELEVANT.

15. Everyone is listening but no one is communicating. ALL?

16. Communication is dangerous. ALL?

17. Earth is deliberately avoided. The "zoo" hypothesis. Interesting. In a class by itself!

I am proposing that ALL of the millions of civilizations have failed at colonization. That's a high bar to meet, that even with some highly unlikely mix of favorable circumstances, not a single one of millions has succeeded at an arbitrarily expanding colonization.

Here is a brief rundown of what is required to have an expanding population of of colonization.

A huge spacecraft must be constructed. Life must be maintained for thousands of years if the spacecraft goes near the speed of light, millions if it doesn't. Long-term stasis might be one option, but it is entirely possible that NO form of intelligent life can survive and thrive after long-term stasis -- space has dangerous objects and dangerous rays. Otherwise, the society with its usual cycle of life and death must function aboard the spacecraft for those thousands or millions of years.

The spacecraft has to stop when it reaches its destination. The energy to set it off from the home planet can be assembled locally, but the energy to stop has to be carried with the spacecraft, and it is huge. Additional energy in similar quantities is required for course corrections, if the aliens detect from their spacehip that there is a more promising place to visit.

Aiming difficulties. Before setting out on this voyage, the colonists have to know where they are going. Perhaps their techniques will let them verify that there is a world which matches their own environment rather closely, and that is not already occupied by a civilization that would not welcome them. But for an expanding pattern of colonization, far more is required: The planet has to have support for a sizable population, lots of heavy industry, and large, accessible quantities of many minerals to construct at least one new colony ship. Suppose for instance aliens with needs like humans detect a planet with a band like our arctic tundra around the equator and glaciers elsewhere. Perhaps colonists could eke out a living, but not build a large industrial base.

Note also that when scientists make estimates of planets that could host life, they mean life that evolved for local conditions. Some other organism that evolved on another planet may have far more specific requirements for their own survival.

There has to be a net gain. Some of the time, a planet has to have at least TWO successful colonizations for this to be an expanding process. If we allow for some of the colonization efforts being failures, we need to replace them and still have a net growth.

Some have proposed a robotic colonization instead of one with living organisms. This does solve some of the problems, for instance relaxing environmental requirements. Our robots on earth are more and more capable with time. But that does not mean that there is no limit to what they can achieve even in the best of circumstances with millions of civilizations trying. A robot needs to quickly find materials allowing it to replicate itself, which are on earth mined from ores and then processed, at great expense. Then they must build a large industrial base, then construct two or more huge spaceships and launch them -- that is indeed a lot of work. What's more, most engineering systems advance by trial and error, getting feedback from earlier attempts to perfect later ones. But if the robot goes a thousand light years away and is even capable of sending information back, the time between one version and the next one improved based on experience is no less than 2,000 years.

I am not a skillful web searcher, but it seems there are far more articles on how robotic probes could proliferate than the immense difficulties. Perhaps this is akin to how conspiracy theories get huge press, and the debunkers write the facts but don't recycle them endlessly.

I have written ALL? In front of most of the proposed limitations, and so I am hesitant to write ALL! In front of this one. But to me it looks like the engineering challenges cannot be overcome by some rare local favorable circumstances, even with millions of civilizations trying.

For us to be surprised that we have not met any aliens, we have to be confident that some civilization somewhere can solve the "TOO FAR" problem to reach over very large expanses of space. The assertion that not a single one can solve that problem seems to me far more likely than any other explanation.

When I think about colonization efforts, I imagine a map of the universe with widely scattered islands of intelligent life. Most are single planets. Here and there just possibly colonization might have happened, proceeding to a small handful of nearby stars, or even merged togther. They form little bubbles. But the bubbles are way too far apart to meet each other reliably, let alone expand to cover the entire galaxy.

This seems by far the most plausible explanation for why we have met no aliens. Earth is not special, so there have been millions of other civilizations throughout our galaxy and others. However, not a single one of those millions can create a colonization effort that can grow arbitrarily large, and thus come into contact with us.

The second most likely explanation is the "Zoo Hypothesis", but that's an explanation for another day.

None of others seems remotely plausible to me.

Why 'Aliens are Plentiful but Unreachable' is an answer everyone hates

 I've been thinking about alien intelligent life again (just got abducted last night again, sigh).

Here is my conclusion again: Aliens are Plentiful but Unreachable. There are various other possible answers to "Is there intelligent life elsewhere?" What's the emotional reaction to each of them?

My answer is about the worst answer I can imagine in terms of human psychology and yearning.Let's go through the others.

If we are alone, then we are truly special, for once. Every other time we thought we were special we actually weren't. This time we are! (If you muse about deities, maybe there really is a personal God, the only one in the Universe, and they care about Earth personally. Just what purpose those billions of other galaxies are serving in God's plan is a mystery, but God's plans always are, right?)

If the reason we won't meet any aliens is that technological civilizations always burn themselves out quickly, that is a doomsday prediction for us here on earth -- and interesting. Maybe we could somehow avoid it! Or we'll fail, but we know they all failed too.

If aliens are close enough to just now pick up our radio signals (as hypothesized in the movie "Contact") then we might just now be coming to their attention, and we can expect a visit! Exciting!

If there are two or three other civilizations in the universe, we can at least dream about them in concrete terms and how they might be different from us. Maybe #1 is like this, and #2 is like that...

The "Zoo Hypothesis" is exciting. Millions of alien civilizations aren't acting independently. One of them is dominant, at least in our vicinity, and powerful enough to keep any other one from making their presence known. This one dominant civilization, for whatever reason, wants to keep us pristine and naive, uncontaminated by knowledge of a much bigger pond in which Earth is just the tiniest fish. That is a motivation we can understand and seems plausible. When and whether they will reveal themselves is a big question. It's a reason to look carefully at the skies because we might at some point learn enough to discover the telltale signs of a zoo. No one said the zookeepers have to have perfect technical prowess.

But then there's my answer. If alien civilizations are to be counted in the millions, then we are nothing special. Just a run-of-the-mill technological civilization. And worse -- we never get to meet the others! It's like the universe saying, "You're not important. There's millions more just like you. But you'll never meet them! I won't tell you a single thing about a single one of them! Nyah-nyah!"