Vsauce - Human Extinction

MASSIVE LONG POST WARNING: feel free to skip this

I usually like Vsauce a lot, but I disagree with just about every assumption and every conclusion he makes in this video.

Anthropogenic vs external extinction event -
I think the likelihood of an anthropogenic extinction event is low. Even in the cold war, at the apex of "mutually assured destruction" risk, IF that destruction was triggered I think it would have been extremely unlikely to make humans go extinct. The US and USSR might have nuked each other to near-extinction, but even with fairly mobile nuclear fallout / nuclear winter, etc. I think that enough humans would have remained in other areas to remain a viable population.

Even if ONE single person had access to every single nuclear weapon in existence, and they went nuts and tried to use them ALL with the goal of killing every single human being on the planet, I still bet there would be enough pockets of survivors in remote areas to prevent humans from going utterly extinct.

Sure, an anthropogenic event could be devastating -- catastrophic even -- to human life. But I think humanity could recover even from an event with an associated human death rate of 95% or more -- and I think the likelihood of anything like that is real slim.

So that leaves natural or external extinction events. The KT extinction (end of the dinosaurs) is the most recent major event, and it happened 65 million years ago. Homo sapiens have been around 150-200,000 years, and as a species we've been through some fairly extreme climatic changes. For example, humans survived the last ice age around 10-20,000 years ago -- so even without technology, tools, buildings, etc. we managed to survive a climate shift that extreme. Mammals survived the KT extinction, quite possible that we could have too -- especially if we were to face it with access to modern technology/tools/knowledge/etc.

So I think it would probably take something even more extreme than the asteroid responsible for KT to utterly wipe us out. Events like that are temporally rare enough that I don't think we need to lose any sleep over them. And again, it would take something massive to wipe out more than 95% of the human population. We're spread out, we live in pretty high numbers on basically every landmass on earth (perhaps minus Antarctica), we're adapted to many many different environments ... pretty hard to kill us off entirely.

"Humans are too smart to go extinct" @1:17 -
I think we're too dumb to go extinct. Or at least too lazy. The biggest threats we face are anthropogenic, but even the most driven and intentionally malevolent human or group of humans would have a hard time hunting down *everybody, everywhere*.

Doomsday argument -
I must admit that I don't really understand this one. The guess of how many total humans there will be, EVER, seems extremely arbitrary. But anyway, I tend to think it might fall apart if you try to use it to make the same assertions about, say, bacterial life instead of human life. Some specific species of bacteria have been around for way way longer than humans, and in numbers that dwarf human populations. So, the 100 billionth bacteria didn't end up needing to be worried about its "birth number", nor did the 100 trillionth.

Human extinction "soon" vs. "later" -
Most plausibly likely threats "soon" are anthropogenic. The further we push into "later", the more the balance swings towards external threats, I think. But we're talking about very small probabilities (in my opinion anyway) on either side of the scale. But I don't think that "human ingenuity will always stay one step ahead of any extinction event thrown at it" (@4:54). Increased human ingenuity is directly correlated with increased likelihood of anthropogenic extinction, so that's pretty much the opposite. For external extinction events, I think it is actually fairly hard to imagine some external scenario or event that could have wiped out humans 100, 20, 5, 2, or 1 thousand years ago that wouldn't wipe us out today even with our advances and ingenuity. And anything really bad enough to wipe us out is not going to wait for us to be ready for it...

Fermi paradox -
This is the most reasonable bit of the whole video, but it doesn't present the most common / best response. Other stars, galaxies, etc. are really far away. The Milky Way galaxy is 100,000+ light years across. The nearest other galaxy (Andromeda) is 2.2 million light years away. A living being (or descendents of living beings) coming to us either of those distances would have to survive as long as the entire history of human life, all while moving at near the speed of light, and have set out headed straight for us from the get-go all those millions and millions of years ago. So lack of other visitors is not surprising at all.

Evidence of other life would be far more likely to find, but even that would have to be in a form we could understand. Human radio signals heading out into space are less than 100 years old. Anything sentient and actively looking for us, even within the cosmically *tiny* radius of 100 light years, would have to have to evolved in such a way that they also use radio; otherwise the clearest evidence of US living here on Earth would be undetectable to them. Just because that's what we're looking for, doesn't mean that other intelligent beings would take the same approach.

Add all that up, and I don't think that the Fermi paradox is much cause for alarm. Maybe there are/have been LOTS of intelligent life forms out there, but they have been sending out beacons in formats we don't recognize, or they are simply too far away for those beacons to have reached us yet.

OK, I think I'm done. Clearly I found the video interesting, to post that long of a rambling response... But I was disappointed in it compared to usual Vsauce stuff. Still, upvote for the thoughts provoked and potential discussion, even though I disagree with most of the content and conclusions.