Why Alien Life Would be our Doom - The Great Filter

00:08:17
https://www.youtube.com/watch?v=UjtOGPJ0URM

Résumé

TLDRThe video explores the implications of discovering extraterrestrial life through the lens of the 'Great Filter' theory, which posits that life may encounter insurmountable challenges preventing it from becoming a galaxy-spanning civilization. Humanity is either special, having already bypassed the most difficult steps in evolutionary progress, or doomed because the Great Filter lies ahead. The discovery of alien life, particularly advanced forms, would imply that humanity’s extinction is probable, as it suggests the Great Filter has yet to occur. Conversely, finding no life elsewhere in the universe would be reassuring, as it would mean humanity has likely passed the Great Filter, ensuring a higher chance of survival and expansion into the cosmos.

A retenir

  • 🧪 The 'Great Filter' is a hypothetical barrier that prevents civilizations from becoming galaxy-wide.
  • 🌌 Discovering alien life might imply that humanity’s long-term survival is unlikely.
  • 🧬 Life on Earth may have overcome rare, difficult evolutionary steps—like complex animal cells.
  • 🧠 Intelligence is not necessarily an evolutionary advantage due to its high costs and risks.
  • 🚀 If the Great Filter lies ahead, it could involve self-destruction through technology or ecosystem collapse.
  • 🌍 Sterile planets might indicate that humanity is rare and special, increasing survival odds.
  • 🔬 The discovery of simple life (like bacteria) would still suggest a dangerous filter ahead.
  • 💀 Advanced civilizations' absence could be due to catastrophic events common to technological species.
  • ❌ Roadblocks like pandemics won't qualify as Great Filters if recovery is possible.
  • 🌌 The best-case scenario involves a lifeless universe full of planets humanity could colonize.

Chronologie

  • 00:00:00 - 00:08:17

    The discovery of alien life, such as bacteria on Mars or ruins on Titan, might not be exciting but alarming. Life's progression can be visualized as ascending stairs, from inanimate matter to complex civilizations. Though life naturally seeks expansion, the absence of observable galactic civilizations in a seemingly vast and life-permitting universe raises a concern: the 'Great Filter.' This theoretical barrier could halt most life forms from advancing beyond a certain step on the stairway, leaving humanity to question if the barrier is behind us or terrifyingly ahead.

Carte mentale

Vidéo Q&R

  • What is the 'Great Filter'?

    The Great Filter is a hypothetical challenge or danger that prevents civilizations from advancing to a galaxy-wide level, possibly dooming them to extinction.

  • Why would finding aliens be bad news for humanity?

    Finding extraterrestrial life would increase the likelihood that the Great Filter lies ahead of us, potentially indicating our extinction is unavoidable.

  • What are the two scenarios related to the Great Filter?

    Scenario 1: The Great Filter is behind us, meaning humanity has overcome the hardest steps of evolution. Scenario 2: The Great Filter lies ahead, meaning a catastrophic event is likely to happen to us.

  • Why might life itself be extremely rare?

    Life may be rare because the conditions for its emergence from dead chemistry are extraordinarily specific and uncommon in the universe.

  • What is the significance of complex animal cells in the Great Filter theory?

    The formation of complex animal cells, which happened only once as far as we know, may be a critical step that's near-impossible to replicate elsewhere in the universe.

  • Could intelligence be a rare phenomenon?

    Yes, intelligence may be rare because it's an expensive evolutionary trait that doesn't always guarantee survival or domination.

  • What might the Great Filter ahead of us look like?

    Potential Great Filters could include catastrophic events like nuclear war, self-destructive technologies, ecological collapse, or super-intelligent AI turning against its creators.

  • Why would sterile planets be seen as good news?

    Sterile planets would suggest that the Great Filter is behind us, increasing the likelihood that humanity is special and capable of becoming a galaxy-wide civilization.

  • What are some examples of potential roadblocks that aren't Great Filters?

    Examples include temporary disasters like a major pandemic or war that humanity could recover from over millions of years, unlike existential threats.

  • What is the best-case scenario according to the video?

    The best-case scenario is that Earth is the only planet with life, suggesting the universe contains billions of lifeless planets we can colonize in the future.

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  • 00:00:00
    Imagine NASA announced today that they found aliens.
  • 00:00:04
    Bacteria on Mars, weird alien fish in the oceans of Europa,
  • 00:00:08
    and also ancient alien ruins on Titan.
  • 00:00:12
    Wouldn't that be great?
  • 00:00:14
    Well, no. It would be horrible news,
  • 00:00:17
    devastating even.
  • 00:00:18
    It could mean that the end of humanity is almost certain
  • 00:00:22
    and that it might be coming soon.
  • 00:00:25
    Why?
  • 00:00:26
    Why would the most exciting discovery of our lifetime
  • 00:00:29
    be bad?
  • 00:00:40
    Let us imagine the development of life,
  • 00:00:42
    from its inception to us today,
  • 00:00:44
    as a flight of stairs.
  • 00:00:46
    The first step is dead chemistry that needs to assemble itself
  • 00:00:49
    into self-replicating patterns, stable and resilient,
  • 00:00:53
    but also able to change and evolve.
  • 00:00:56
    The second step is for our early life to become more complex,
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    able to build more complicated structures,
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    and use the available energy much more efficiently.
  • 00:01:05
    On the next step, these cells combine to become multicellular beings,
  • 00:01:10
    enabling unbelievable variety and further complexity.
  • 00:01:14
    The step above sees the species evolve big brains,
  • 00:01:17
    enabling the use of tools, culture and shared knowledge,
  • 00:01:21
    which creates even higher complexity.
  • 00:01:24
    The species can now become the dominant lifeform on its planet,
  • 00:01:27
    and change it according to its needs.
  • 00:01:30
    First shy attempts to leave its planet are happening.
  • 00:01:33
    This is where we are now.
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    It's in the nature of life as we know it
  • 00:01:37
    to reach out, to cover every niche it can.
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    And since planets have a limited carrying capacity and lifespan,
  • 00:01:44
    if a species wants to survive,
  • 00:01:46
    it will look for more places to spread to.
  • 00:01:49
    So the steps above the current ones seem logical:
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    colonize your own solar system,
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    then spread further to reach other stars,
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    to the possible final step: becoming a galaxy-wide civilization.
  • 00:02:02
    It's very likely that this is a universal principle for civilizations,
  • 00:02:07
    no matter where they're from.
  • 00:02:09
    If a species is competitive and driven enough to take control over its planet,
  • 00:02:13
    they'll probably not stop there.
  • 00:02:16
    We know that there are up to 500 billion planets in the Milky Way,
  • 00:02:20
    at least 10 billion Earth-like planets.
  • 00:02:23
    Many have been around billions of years longer than Earth.
  • 00:02:26
    But we're observing zero galactic civilizations.
  • 00:02:30
    We should be able to see something...
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    ...but there's nothing.
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    Space seems to be empty and dead.
  • 00:02:37
    This means something is preventing living things from climbing the staircase,
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    beyond the step we're on right now.
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    ...Something that makes becoming a galactic civilization
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    extremely hard, maybe impossible.
  • 00:02:53
    This is the Great Filter.
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    ...A challenge or danger so hard to overcome,
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    that it eliminates almost every species that encounters it.
  • 00:03:02
    There are two scenarios:
  • 00:03:04
    One means we are incredibly special and lucky,
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    the other one means we are doomed and practically already dead.
  • 00:03:13
    It depends on where the filter is on our staircase:
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    behind, or ahead of us?
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    Scenario 1:
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    Scenario 1: The filter is behind us.
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    We are the first.
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    If the filter is behind us,
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    that means that one of the steps we passed
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    is almost impossible to take.
  • 00:03:31
    Which step could it be?
  • 00:03:33
    Is life ITSELF extremely rare?
  • 00:03:36
    It's very hard to make predictions about how likely it is
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    for life to emerge from dead things.
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    There is no consensus.
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    Some scientists think it develops everywhere where the conditions are right;
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    others think that Earth might be the
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    ONLY living place in the universe.
  • 00:03:52
    Another candidate is the step of complex animal cells.
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    A very specific thing happened on this step,
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    and as far as we know, it happened exactly once.
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    A primitive hunter cell swallowed another cell,
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    but instead of devouring it, the two cells formed a union.
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    The bigger cell provided shelter,
  • 00:04:11
    took care of interacting with the environment and providing resources,
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    while the smaller one used its new home and free stuff,
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    to focus on providing a lot of extra energy for its host.
  • 00:04:22
    With the abundant energy, the host cell could grow more than before
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    and build new and expensive things to improve itself,
  • 00:04:30
    while the guest became the powerhouse of the cell.
  • 00:04:33
    These cells make up every animal on the planet.
  • 00:04:36
    Maybe there are billions of bacteria-covered planets in the Milky Way,
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    but not a single one, apart from us,
  • 00:04:43
    has achieved our level of complexity.
  • 00:04:46
    ...or intelligence.
  • 00:04:47
    We humans feel very smart and sophisticated
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    with our crossword puzzles and romantic novels.
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    But a big brain, is first and foremost,
  • 00:04:54
    a very expensive evolutionary investment.
  • 00:04:57
    They are fragile,
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    they don't help in a fistfight with a bear,
  • 00:05:01
    they cost enormous amounts of energy,
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    and despite them, it took modern humans,
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    200,000 years to get from sharp sticks to civilization.
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    Being smart does not mean you get to win automatically.
  • 00:05:13
    Maybe intelligence is just not so great,
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    and we're lucky that it worked out for us.
  • 00:05:19
    Scenario 2:
  • 00:05:20
    Scenario 2: The filter is ahead of us.
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    Plenty of others died already.
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    A Great Filter before us is orders of magnitude more dangerous
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    than anything we encountered so far.
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    Even if a major disaster killed most of us or threw us back thousands of years,
  • 00:05:36
    we would survive and recover. And if we can recover,
  • 00:05:39
    even if it takes a million years, then it's not a Great Filter,
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    but just a roadblock to an eventual galactic civilization.
  • 00:05:47
    On universal timescales, even millions of years are just the blink of an eye.
  • 00:05:52
    If a Great Filter really lies before us,
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    it has to be so dangerous,
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    so purely devastating and powerful,
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    that it has destroyed most, if not all,
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    advanced civilizations in our galaxy
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    over billions of years.
  • 00:06:06
    A really daunting and depressing hypothesis
  • 00:06:09
    is that once a species takes control over its planet,
  • 00:06:12
    it's already on the path to self-destruction.
  • 00:06:16
    Technology is a good way to achieve that.
  • 00:06:19
    It needs to be something that's so obvious,
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    that virtually everybody discovers it,
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    and so dangerous, that its discovery leads almost universally
  • 00:06:28
    to an existential disaster.
  • 00:06:30
    A large-scale nuclear war,
  • 00:06:33
    nanotechnology that gets out of control,
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    genetic engineering of the perfect super bug,
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    an experiment that lights the whole atmosphere on fire.
  • 00:06:42
    It might be a super-intelligent AI
  • 00:06:44
    that accidentally (or purposely) destroys its creators.
  • 00:06:49
    Or things that we can't even see coming right now.
  • 00:06:52
    Or it's way simpler:
  • 00:06:54
    species competitive enough to take over their planet
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    necessarily destroy it while competing with each other for resources.
  • 00:07:01
    Maybe there are runaway chain reactions in every ecosystem
  • 00:07:05
    that once set in motion, are not fixable.
  • 00:07:08
    And so once a civilization is powerful enough to change the composition of its atmosphere,
  • 00:07:13
    they make their planet uninhabitable
  • 00:07:15
    100% of the time.
  • 00:07:17
    Let's hope that that's not the case.
  • 00:07:20
    If the filter IS ahead of us,
  • 00:07:22
    our odds are really bad.
  • 00:07:24
    What we can hope for.
  • 00:07:26
    THIS is why finding life beyond Earth would be horrible.
  • 00:07:30
    The more common life is in the universe,
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    and the more advanced and complex it is,
  • 00:07:35
    the more likely it becomes that a filter is in front of us.
  • 00:07:39
    Bacteria would be bad,
  • 00:07:40
    small animals would be worse,
  • 00:07:42
    intelligent life would be alarming.
  • 00:07:45
    Ruins of ancient alien civilizations...
  • 00:07:48
    would be horrible.
  • 00:07:50
    The best case scenario for us right now
  • 00:07:52
    is that Mars is sterile,
  • 00:07:55
    that Europa's oceans are devoid of life,
  • 00:07:57
    and the vast arms of the Milky Way
  • 00:07:59
    harbor only empty oceans hugging dead continents.
  • 00:08:04
    ...That there are billions of empty planets waiting to be discovered
  • 00:08:07
    and to be filled up with life.
  • 00:08:10
    Billions of new homes...
  • 00:08:12
    waiting for us...
  • 00:08:14
    to finally arrive.
Tags
  • Great Filter
  • extraterrestrial life
  • evolution
  • alien civilizations
  • existential risk
  • life on Mars
  • Fermi paradox
  • cosmic survival
  • advanced technology
  • humanity's future