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Our future, our universe, and other weighty topics

Friday, December 15, 2017

Fake Physics Does Not Explain Real Cosmic Fine-Tuning

Marcus Du Sautoy is a mathematician who has taken over Richard Dawkin's chair as Charles Simonyi Professor for the Public Understanding of Science at Oxford University. While holding that chair, Dawkins committed many an error in reasoning, some of which are described here. Some equally bad errors of reasoning are committed in Du Sautoy's book The Great Unknown.

On page 221 Du Sautoy marvels at how fine-tuned the fundamental constants of our universe seem to be. He states:

What is particularly striking is how sensitive the possibility of life in our universe is to a small change in these constants. For example, if the constant that controls the way the electromagnetic field behaves in a vacuum is changed by four percent, then fusion in stars could not produce carbon....Change the cosmological constant in the 123rd decimal place and suddenly it's impossible to have a habitable galaxy.

Du Sautoy suggests what he calls an “explanation” for this mystery – the idea of the multiverse, that there exists some vast collection of universes. He says, “In the multiverse model there are lots of different universes, and in each of these universes the fundamental constants could be randomly assigned.” That is indeed the idea of the multiverse, although Du Sautoy misspeaks by referring to “the multiverse model.” In science a model is a simplified representation of a known physical reality. Speculating about unknown or unobserved universes is not at all a case of making a scientific model.

Next Du Sautoy goes off the rails, both by the very fact of referring to the multiverse idea as an explanation, and also by claiming, most absurdly, that such an idea is a simple and economical explanation. He states the following on page 222:

The multiverse theory at least has that sense of economy we are after in a good theory. The explanation terminates and does not require further explanation. The addition of these other universes is just more of the same with variations, and once you accept all these other universes you get a complete solution to the fine-tuning problem....A good scientific theory should make sense of how everything is put together, and shouldn't need to introduce too many extra characters into the story to get the narrative we experience. There is a simplicity and naturalness about the multiverse theory that makes it a strong candidate theory.

Reading Du Sautoy claim that a multiverse is a simple explanation to the problem of why our universe is so fine-tuned, I am reminded of Voltaire's famous quip about the Holy Roman Empire: that it was neither holy nor Roman nor an empire. The multiverse is not at all an explanation and not at all simple. You present an explanation when you either discuss some causal factor that produced something, or you present some circumstances that allow you to say, “Now what seemed so surprising is not surprising.” In neither of these senses is the multiverse idea an explanation. Imagining some vast collection of other universes does not involve some causal factor that preceded our universe, making it have fine-tuned constants. If we imagine such a vast collection of universes, it is still every bit as surprising that our particular universe should so improbably have fine-tuned characteristics it was so unlikely to have.

Imagine if some teenager buries all the furniture in his house in buckets of honey. You could try to explain this by claiming there is an infinity of other universes, and so in at least one such universe we would expect such behavior. But that is in no sense an explanation, because it does nothing to increase the likelihood that this particular teenager would have acted the way he did. Our surprise about the teenager's behavior is not reduced, so in no sense has an explanation occurred. We can say the same thing about a multiverse as an attempted explanation for our universe's incredibly improbable fine-tuned constants. Imagining a multiverse does nothing to make it more likely that our particular universe would have such fine-tuned constants, so it is not correct to say that any explanation has occurred for our universe's characteristics.

Although he is a mathematician, Du Sautoy has ignored a mathematical rule very relevant to these considerations. The rule is that you do not increase the likelihood of a success on any one random trial no matter how much you increase the number of random trials. Each universe is like a random trial in which the success is the appearance of intelligent life. You do not increase the chance of success on any one trial by increasing the number of trials. So even if you assume an infinity of universes, that does not increase by even .00000000000000001 percent the likelihood that our particular universe would have coincidentally been consistent with life. And similarly, if I assume that there are an infinity of casinos, and an infinity of gamblers at such casinos, this does not increase by even .00000001 percent the likelihood that I will be a winner the next time I gamble at a casino.

As for Du Sautoy's claim that the multiverse idea is a simple and economical theory,  this is certainly the exact opposite of the truth, for nothing could be less simple and less economical than imagining some vast collection of other universes, each with a different set of fundamental constants. Du Sautoy has previously told us that the cosmological constant seems to be fine-tuned to something like one part in 10 to the 123rd power. So his multiverse presumably needs to consist of more than 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 universes. Calling a theory requiring such a thing simple and economical is every bit as fatuous as calling the Pacific Ocean “dry” or the Sahara Desert “wet.”


On page 223 Du Sautoy attempts to suggest that a multiverse theory is better than imagining a designer who fine-tuned the universe's constants, because “a designer who fine tunes the constants raises as many questions as it answers.” But, of course, exactly the same objection can be made to the infinite clutter of a multiverse, which raises far more questions than it answers, such as the question of where this vast collection of universes came from, and why all these universes happened to have the characteristics they have. And it is not a valid procedure to judge an explanation on whether it raises as many questions as it answers. All kinds of successful theories (such as the atomic theory) raised as many questions as they answered.

Du Sautoy suggests that a multiverse is a better explanation because it's not supernatural. But he's wrong – there's nothing more supernatural than a multiverse. The Merriam-Webster defines supernatural as “of or relating to an order of existence beyond the visible observable universe.” A vast collection of universes (each with different physical constants) outside of our universe is just such a thing.

On page 225, Du Sautoy states, “Although at the moment there is no way of testing the multiverse theory, there is no a priori reason why it will always remain untestable.” This is completely false; there is exactly such an a priori reason. It is the fact that we could never verify that there existed even one other universe with some set of physical constants different from our own.

On the same page, Du Sautoy states the following:

The multiverse theory, although potentially untestable, does come with a mechanism, inflation, by how these multiverses arise. And we do at least have evidence for one of these multiverses: our own universe.

The second statement is a clumsy misstatement, and the first statement is misleading. According to multiverse terminology, a multiverse is some collection of many individual universes. Our universe is therefore not a multiverse, but a universe. Our universe is no more evidence for a multiverse than a single tree is evidence for a forest.

As for the claim that inflation theory provides a mechanism for creating universes, this is not true in any relevant sense. Certain versions of the theory of cosmic inflation (itself a speculation designed mainly to explain evidence for a certain type of cosmic fine-tuning) imagine that our universe is kind of like a bubble in a larger cosmic reality that pops out bubble universes, kind of like a hot soup pops out bubbles. But this cosmic inflation theory has no mechanism for creating other universes with random physics and random physical constants. The “bubble universes” of the theory of eternal cosmic inflation should have the same physical constants as our universe. This point was made by Columbia University multiverse critic Peter Woit, who states the following:

Claims are often made that the theory of inflation provides evidence for a multiverse with different physics in each universe. If one looks into actual models of inflation one finds that again, no theory of the sort has been claimed.

Woit reiterates the same point here, stating “models of inflation...are not models that lead to the kind of multiverse of different physical laws.” Over the years, Woit's “Not Even Wrong” blog has been great about exposing the misstatements and malarkey of multiverse theorists. Woit now uses the term “Fake Physics” to describe such theories.

Moreover, since the cosmic inflation theory is a speculative theory for which there is no solid evidence, it can hardly be used to back up claims of a multiverse, no matter what it predicts or describes. Trying to do that is very much like a person trying to substantiate his claim of a vast horde of invisible fairies by saying that his other theory of a fourth-dimensional magic kingdom provides a mechanism for the appearance of such fairies. You do not substantiate one speculation by referring to another speculation.

Although perhaps sympathetic to his naturalism, Woit was scolding biologist Jerry Coyne, who recently had a post enthusing that maybe the multiverse can help us explain the appearance of human beings such as us. In a post with the misleading title "New evidence for the multiverse -- and its implications," Coyne states:

Further, it means that the evolution of humans was inevitable somewhere. In one of those universes that permitted the evolution of life, it was inevitable that a thinking hominin would evolve.

We may ask here: why does Coyne feel the need to drag in a multiverse (a vast collection of universes) to help explain the appearance of humans such as us? This is not at all what anyone should be doing if he felt that he had an adequate Darwinian explanation for human beings. On the other hand, someone who did not have an adequate Darwinian explanation for human beings might, in an act of utter desperation, try to imagine an infinity of universes to help explain human origins. But the problem is that exactly the same “it would happen at least once in an infinity of universes” reasoning can be used to justify a belief in fairies and leprechauns.

All these attempts to explain our universe's fine-tuned constants through imagining a vast collection of universes are guilty of a fallacy we may call the lucky numbers fallacy. This is the fallacy of assuming that some favorable set of physical constants would be sufficient to make the universe habitable for beings such as us. Having favorable physical constants is a necessary condition for a habitable universe, but not a sufficient condition. You need something much more than such lucky numbers. For a universe to be habitable, you also need favorable laws of nature, which act programmatically to help create favorable conditions for life. Such laws act like intelligent programming. If there were an infinite set of random universes, we would not expect that any of them would have such a favorable set of laws like those in our universe. There would be no reason why any random universe would have laws resembling intelligent programming.

As for Coyne's idea that a multiverse might help explain humans, it is completely mistaken. Human minds have many characteristics that we cannot explain as being a result of natural selection or brain activity. As discussed here, human mental characteristics such as empathy, spirituality, mathematical ability, abstract thinking, musical ability, aesthetic appreciation, and artistic creativity are ones that do not have any survival benefit to organisms in the wild, so we cannot explain them by evoking natural selection. The most basic things such as consciousness and life-long memory cannot be explained by brain mechanisms. Besides having no plausible theory to explain human memories lasting for decades, scientists lack any explanation for how neurons could be producing human consciousness. Human minds have characteristics that can only be explained by imagining something beyond the brain: something such as soul or spirit. So no matter how many combinations of matter that might occur in an infinity of universes, not one single one of them would ever be sufficient to explain the human mind. You can't multiverse your way to explaining minds such as ours.

As shown in this post's table, we see many astonishing examples of fine-tuning both in the universe's laws and fundamental constants. We cannot explain away these things through infinitely extravagant multiverse speculations that Woit has recently labeled “Fake Physics.” Fake Physics does not explain real cosmic fine-tuning. 

Monday, December 11, 2017

He's Off on a Wild Goose Chase to Help Save a Sinking Paradigm

The leading doctrine concerning how memory is stored is the doctrine that memory is stored by a process of the strengthening of synapses of brains. But what we know about the lifetimes of proteins in synapses contradicts this doctrine. Humans can remember old memories for as long as 50 years. But as far as we know, the proteins in synapses have lifetimes no longer than a few weeks. How could memories be stored in synapses that have their parts being constantly replaced? That would be like storing an essay written on leaves on a table, when the wind is frequently blowing away the leaves, and replacing them with other falling leaves -- not something suitable for long-term information storage. 

This paper finds that synaptic proteins turnover at a rate of about 17% per day. This paper says that a study of 90 synaptic proteins found an average lifetime of only about 12 days, with the most long-lived one lasting only 48 days. 

Such a fact is extremely troubling to those who think that long-term memory is stored in your brain. So what do you when there is a troubling fact that contradicts your theory of memory? You ask the government for lots of money to look for something that might help out your bad theory, even though that there is no evidence that the thing you are looking for exists.

That seems to be what is going on in the case of National Institute of Health Project # 1R01MH112152-01A1, described here. Some $610,745 has been granted to Richard L. Huganir of Johns Hopkins, so that he can look for “exceptionally long-lived proteins” in synapses. Given what we know about the extremely short lifetimes of synapse proteins, this seems to be like getting lots of money from the government to look for flying rats.

Below is an excerpt from the grant proposal:

Most of the individual proteins that are known to make up the synapse will turnover, being degraded and replaced within hours to a few days. Therefore the question remains as to what physical substrates underlie the persistence of long-lasting memories. One possibility is that exceptionally long-lived proteins (LLPs) reside in synapses and act as molecular anchors to maintain the synaptic strength or a network property that defines a given memory.

The grant proposal admits that there is no evidence that any such “exceptionally long-lived proteins” exist in synapses, for it says, “no studies to date have addressed whether such proteins exist at synapses and contribute to the establishment and maintenance of long-term memories.”

Given the known extremely short lifetimes of synaptic proteins, we should characterize this research project as a wild goose chase. It seems to be kind of a desperate shot-in-the dark to try to save the materialistic paradigm's claims about memory. No doubt our neuroscientists are troubled by the idea that because of synapse proteins with very short lifetimes, the brain is simply not up to the job of storing memories for years. That would seem to mean we could only explain human 50-year memories by supposing that our minds must involve something more than the brain, such as a soul or some mysterious immaterial consciousness infrastructure.

There is no reason to think that Huganir will find any synapse protein that can last for years.  Let's suppose you were to make the very surprising discovery that some protein in synapses lasts for years. We would still know that almost all the proteins in synapses are very short-lived. So the discovery of such a long-lived synapse protein would be futile. It would be like trying to explain the persistence of a much-used book supposedly lasting 50 years – a book made almost entirely of gossamer spider-web pages – by finding that every twentieth page is not made of flimsy short-lived gossamer but of paper. That doesn't do you much good in explaining how most of the book's information could persist for 50 years.

I may note an irony here. Human observers have got much evidence for astonishing things that cannot be explained by modern science: things such as extrasensory perception, apparition sightings, mysterious orbs with highly repeating stripe patterns, and near-death experiences. Such things challenge the dogmas of the materialistic  paradigm. If you were to ask for a half million dollars for a government grant to investigate further such things which have already been extensively observed, you would be turned down quickly, and you would be told: not one cent for such research. But if you seem to be in service of prevailing dogmas, you will have no problem getting a half million dollar grant to go on a quixotic quest looking for something that has never been observed, which is what Huganir has got. I guess the rule is: there's no government research money for anything that might challenge the materialistic paradigm, but plenty of government research money for any project that might help patch one of the many holes that have sprung up in such a paradigm, which are threatening to sink the paradigm. 

The government seems to have been very generous in giving lots of grants to Huganir, who we can assume is mainly involved with projects with a larger chance of success than this one.

Thursday, December 7, 2017

How to Get Your Weak Scientific Theory Accepted

Imagine you create some scientific theory, and you want the theory to be generally accepted in some corner of the academic world. You might think that this is an incredibly hard task, requiring that you both come up with a new theory and somehow marshal convincing evidence showing that the theory is correct. But it may not be so hard. The world of scientific academia is often not a world of dispassionate judges weighing evidence with great objectivity. It is often a world in which sociological effects, psychological effects and ideology play a large role. So the path to getting the academic world to accept your theory may not be so difficult, and there are techniques you might use to get even a very weak or dubious theory accepted by the academic world.

The first step is to get some scientific paper published describing your weak theory. This is not particularly hard to do, because there are ways to make weak ideas seem rather impressive-sounding. The first way (very commonly used) is to load almost every paragraph of your paper with dense, all-but-impenetrable technical jargon. Such jargon will impress lesser reviewers of your paper.

The second way to make your weak theory sound rather impressive is to load up your paper with obscure mathematics. You need not worry that anyone will complain that the mathematics were irrelevant, for almost no one makes such a complaint about scientific papers, even when the mathematics is absurdly extraneous. The all-but-incomprehensible math in your paper may impress some peer reviewers of your paper, giving them the impression that your weak theory is a weighty intellectual contribution.

Once your paper is published, you will need to start leveraging the popular press, so that some articles about your theory will appear in magazines and online web sites. The first step is to get your college or university to release a fawning press release trumpeting your weak scientific paper and claiming that it is a stunning breakthrough. This is very easy to do. The writers of university press releases are a very compliant lot, and will be unlikely to challenge your extravagant claims. The rule for university press releases seems to be that it is okay to trumpet utterly far-fetched claims, as long as such claims somehow seem to shed glory and prestige on the university.

Then you may have to reach out to some science journalists to get them to write about your weak scientific paper. This is not very hard to do. Today's science journalists are very often docile and compliant “pom-pom journalists” eager to repeat any claim you may make to have achieved a “stunning theoretical breakthrough.” There will be very little chance that the science journalists you contact will subject your claims to much critical scrutiny.

Having got some press coverage, you now need to reach out to a few of your pals in the academic world, to get them to make supportive comments about your weak theory. This will probably not be very hard, as the world of academia has countless “I'll scratch your back if you scratch mine” relationships. If you have been a professor for many years, you probably know quite a few people who owe you favors, such as people whose books you favorably commented on.

You can then start using authority techniques, by calling your weak theory “science.” Using such verbiage will be like sprinkling magic fairy dust, and will cause many a person to start treating your weak theory with great respect. If someone objects, claiming that science is best defined as facts that have been determined by observation and experiment, and that there are no such facts substantiating your weak theory, you can respond by presenting an alternate definition: the much looser definition (recently stated by a scientist blogger) that science is simply whatever scientists are working on. Of course, under such a definition every weak theory published in a scientific journal is “science.” 

weak theory

The next step requires audacity. The idea is to start claiming that your theory is starting to achieve mass acceptance among your little tribe of scientific peers. There are various artful expressions you can use to make such a claim. For example, you can say that “a consensus is starting to emerge” that your theory is correct, or that “a growing number of experts” are adopting your theory. No one will be likely to challenge these claims, which are hard to verify.

The next step requires even more audacity. At some point you can stick your neck out and claim that there is now a consensus of experts in your field who believe that your theory is correct. Such a claim will be difficult or impossible to verify, but it will have enormous force and power from the sociological perspective of the bandwagon effect. If people hear such a claim repeated enough times, then your theory will get all kinds of new supporters who never would have adopted it, but who will now adopt it just because they want to run in the direction they think the herd is running. No one wants to be in defiance of a consensus of experts. So countless people will flock to your weak theory the moment they hear that there is a consensus of experts in favor of your theory, even if no such consensus has really developed. Claims that a consensus of experts has agreed on something often are kind of self-fulfilling claims that help cause such a consensus to appear because of a sociological bandwagon effect.

This step may fail, and you may fail to get people to accept your claim that there is a consensus of experts in favor of your weak theory. But if you get people to accept such a idea, even if a consensus does not yet exist, then your work is almost done. The bandwagon effect will continue, the snowball effect will keep rolling, and your theory will have triumphed in some little corner of the academic world.

There may still remain many who think that your theory is pure nonsense. But since you have now got something you can claim to be a consensus of experts, you can now make use of a technique that is incredibly popular in the academic world: the technique of nonconformity shaming tactics. You could employ this technique, by calling your weak theory “science,” and demonizing all who oppose it as “anti-science.” Few will object in the academic world, where the term “anti-science” is shamelessly employed with reckless abandon, such as by those who call anyone preferring not to consume gene-spliced food as “anti-science.”

Your efforts in this regard will be enormously more likely to succeed under two cases: (1) if your weak theory allows scientists to enhance their prestige by triumphally claiming that they have solved some long-standing mystery; (2) if your weak theory allows scientists to claim they have an explanation for some event or phenomenon that does not fit in with their claims that everything can be explained by random physical processes. In the latter case, there will be a kind of “ideology boost” that will make your theory 300% or 400% more likely to be accepted than if it had no ideological relevance. Your fellow scientists will show almost infinite tolerance for accepting silliness in theories that seem to help them evade what they most dread: that there may be spirits or souls, or that the universe or life may be the result of intentional purpose.

Yes, given the very strong influence of sociological and ideological factors in the success of academic theories, you could use all of these tactics to get the academic world to adopt your weak theory. But you would not be a very honest person if you did that. It would be much better to not do such things as I have mentioned here, and to have greater intellectual integrity, even at the price of having less success in getting people to adopt your theory. And it is much better to honestly admit your ignorance about some great mystery than to get the academic world to accept some very dubious theory of yours about that mystery, some theory that does not warrant belief.

Sunday, December 3, 2017

A Scientist's Weird Hope About Extraterrestrials

In his new book Life 3.0 MIT physicist Max Tegmark confesses a strange hope he has about the search for extraterrestrial life: that it finds nothing. Below is his reasoning on page 245 of the book:

Although I'm a strong supporter of all the ongoing searches for extraterrestrial life, which are shedding light on one of the most fascinating questions in science, I'm secretly hoping that they'll all fail and find nothing! The apparent incompatibility between the abundance of habitable planets in our Galaxy and the lack of extraterrestrial visitors, known as the Fermi paradox, suggests the existence of what the economist Robin Hanson calls a “Great Filter,” an evolutionary/technological roadblock somewhere along the developmental path from the non-living matter to space-settling life. If we discover independently evolved life elsewhere, this would suggest primitive life isn't rare, and that the roadblock lies after our current human stage of development – perhaps because space settlement is impossible, or because almost all advanced civilizations self-destruct before they're able to go cosmic. I'm therefore crossing my fingers that all searches for extraterrestrial life find nothing: this is consistent with the scenario where evolving intelligent life is rare but we humans got lucky, so that we have the roadblock behind us and have extraordinary future potential.

Tegmark presents here rather concisely an argument similar to the argument presented by philosopher Nick Bostrom in this paper. The argument can be stated like this:

  1. There must be some Great Filter which makes it very unlikely that planets produce civilizations that spread throughout the galaxy – something such as an unlikelihood of life originally appearing, an unlikelihood of intelligence ever appearing, an unlikelihood of interstellar travel, or an unlikelihood of a civilization surviving for long.
  2. Such a Great Filter can either be in our past or our future (for example, if the Great Filter is the unlikelihood of life ever appearing on a planet, then the Great Filter is in our past, and we have already leaped over this hurdle).
  3. If the Great Filter is in our future, we should be very sad, because it will mean our civilization will probably not last very long.
  4. But if the Great Filter is in our past (some hurdle we have already jumped over), then we are in good shape, and our future is bright (the whole galaxy might be ours for the taking).
  5. If we discover life on another planet, it is evidence that life commonly evolves in our galaxy, and this shows that the Great Filter must be in our future, and that we won't last very long.
  6. Therefore, it is bad news if we discover any extraterrestrial life.

There are multiple problems involved in this line of reasoning. The first is the problem of assuming that extraterrestrials have not spread throughout the galaxy. We do not know that such a thing has not occurred. UFO sightings may provide evidence against such an assumption. The fact that Earth has not been colonized by extraterrestrials is no proof that some other civilization has not spread throughout the galaxy. It is quite possible that a civilization spreading throughout the galaxy would not colonize every habitable planet, but leave some planets as kind of zoos or nature reserves. When descendants of Europeans spread throughout North America, they did not fill the whole continent with settlements, but preserved quite a bit of North America as nature preserves. A similar conservation principle could be observed by some galactic civilization spreading across a galaxy. Or it might be impractical to colonize every habitable planet, for any number of technical or logistical reasons.

Another problem with the line of reasoning cited above is that it commits a fallacy along the lines of stating: if we discover extraterrestrial life, that would show the Great Filter is in the future, not our past. The discovery of any type of life other than civilized intelligent life would not at all do such a thing. Let's consider various possible candidates for a Great Filter:

great filter

Now after reviewing all of these possible candidates for a Great Filter, it should be clear that the mere discovery of some type of extraterrestrial life would not by any means show that this Great Filter is something that mankind has not yet overcome. For example, if some very simple prokaryotic microscopic life were to be discovered on Mars or a moon of Jupiter or Saturn, that would still leave standing the last seven of these candidates as possibilities, including the “Multi-cellular Life” filter that it is too hard for multi-cellular life to appear from microscopic life. And if we were to discover signs of oxygen in the atmosphere of a distant planet, suggesting that photosynthesis had occurred, that would still leave standing the filters such as the “Intelligence” filter and the “Language and Civilization” filter. It would still be perfectly possible that the Great Filter is that it is too hard for intelligent language-using tool-making life to appear.

So Tegmark is very much in error when he states, “If we discover independently evolved life elsewhere, this would suggest primitive life isn't rare, and that the roadblock lies after our current human stage of development – perhaps because space settlement is impossible or because all advanced civilizations self-destruct before they're able to go cosmic.” Discovering primitive life would do no such thing, as it would still leave standing as candidates for the Great Filter such possibilities as the “Intelligence” filter and the “Language and Civilization” filter. Discovering primitive life would still leave standing the possibility that it is very unlikely that life would ever evolve to a state of intelligence, language-use, tool-making and civilization, and that such a difficulty is the Great Filter.

And, similarly, Nick Bostrom committed the same error when he stated the following:

And if we discovered the fossils of some very complex life form, such as of some vertebrate-like creature, we would have to conclude that the probability is very great that the bulk of the Great Filter is ahead of us. Such a discovery would be a crushing blow. It would be by far the worst news ever printed on a newspaper cover.

This is completely wrong. From such a discovery, it would not by any means be true that we would have to conclude that the probability is very great that the bulk of the Great Filter is ahead of us.” For there would still be standing the “Intelligence” filter and the “Language and Civilization” filter. It would still be perfectly possible that it is exceptionally rare for life to evolve to a state of intelligence, language-use, tool-making and civilization, and that such a difficulty is the Great Filter. If you think that intelligence, language-use, tool-making and civilization automatically follows once large-scale life exists, consider the fact that humans have a whole range of mental characteristics (including spirituality, artistic creativity, mathematical ability, philosophical reasoning, intellectual curiosity, imagination, and language use) that cannot be explained by appealing to natural selection, as these are things that do not increase an organism's chance of surviving until reproduction. Some evolution experts have argued that the appearance of something like humanity was extremely improbable. Until we discover some extraterrestrial civilization, it is still a very viable possibility that it is incredibly rare for life to evolve into civilized language-using life.

The only discovery that might allow us to reasonably say that the Great Filter is in our future and not our past would be the discovery of civilized life elsewhere in space. Would that be something that would be a cause for grief and sorrow, along the lines Tegmark and Bostrom have suggested? Would such a discovery tell us something negative about our future?

No, simply because the very moment such a discovery was made, the very idea of a Great Filter would be discredited. In our current state of knowledge, lacking any proof for extraterrestrials, this idea of a Great Filter has significant weight. But at the very moment we discovered proof of an extraterrestrial civilization, the idea of a Great Filter would be discounted and discredited. People would start saying: evidently this idea of a Great Filter isn't very sound, if we have already discovered an extraterrestrial civilization. They would also start saying: if we have already discovered one extraterrestrial civilization, there must be many others in our galaxy. The discovery of an extraterrestrial civilization would be a crippling blow to the very idea of a Great Filter.

We can therefore imagine no circumstances under which it would make sense to lament and grieve over a discovery about extraterrestrial life, on the grounds that it told us something negative about our future. Discovering anything less than civilized intelligent life would do nothing to prove the idea that the Great Filter is in our future and not our past. And if we did discover civilized intelligent life, the very idea of a Great Filter would instantly be so discredited that it would at that point not make sense to be drawing conclusions about our future based on such a concept.