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Comment by Svip | Hacker News Reader

Wait, I thought the purpose of life flashing before your eyes is that the brain is trying to find a past event, that might help avoid the impending death. On QI, though I cannot remember the episode, they told a story of a swimmer, who encountered a shark, and suddenly his life flashed before his eyes, thinking he was going to die. In the slides of memories, he saw his son watching a DVD about punching a shark on the nose. So he did, and it saved his life.

That explanation makes a lot of sense to me. The brain is convinced that death is imminent, and has no time to go through the normal procedure of remembering, so it just pulls up as many memories it can to the forefront, in hope that one of them might provide the answer to prevent death.

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This is exactly the sort of plausible just-so story I would expect from QI.

On another episode, Stephen Fry explains with no doubt equal earnestness that the fins on a Saturn V rocket are there to generate lift as it travels through the atmosphere.

It's fun, as any panel show helmed by Fry certainly would be. But you don't want to put too much faith in what you hear on it, at least in advance of checking with a credible source.

They have a pretty solid research team (https://qi.com/elves), and they often do segments about times they've gotten things wrong, or the science has changed etc.

It is first and foremost an entertainment program, so yeah.

The Elves make an excellent podcast that I highly recommend to others.

I think this is a case of a word having one colloquial meaning and a different technical meaning. If you "lift" something, you're probably picking it up.

In a hydrodynamic sense, "lift" is a force on a foil moving through a fluid. This kind of lift is a force orthogonal to the direction of motion through the fluid and the surface of the foil. That could be upward lift, like that on the wings of an aircraft. That could also be the forward and leeward lift on the sail of a sailboat, or the windward lift on the sailboat's keel. It could also be the lateral, stabilizing lift on the control surfaces of a rocket.

Maybe hydrodynamic lift is what was meant, but if so, it wasn't well described; it sticks out in memory precisely because he made it sound like the fins contributed on net to reaching orbital energy and I might've yelled at the screen a little bit about that.

Doesn’t make sense from an evolution theory viewpoint to me.

If that has advantages to survival, there would have to be many survivors who have experienced this.

Also, I think shark story is different from this one. At no time, that swimmer was about to die (that could change soon, but wasn’t happening yet). His brain was intact, not dying.

My personal (completely unsupported) theory for the case where your brain is actually dying is that it’s plasticity of the brain at work. As brain cells die, the brain moves around the most important stuff to keep it in working cells. That, to me, makes evolutionary sense. You could use that kind of machinery all your life. That it goes into overdrive when it doesn’t help anymore because your entire brain is about to die would be a side effect.

Alternatively, it’s because we’re living in a simulation, and the caches get flushed to more permanent storage, starting with the more important stuff ;-)

> Doesn’t make sense from an evolution theory viewpoint to me.

If that has advantages to survival, there would have to be many survivors who have experienced this.

Everyone who has ever reported this has survived.

I love hearing from the evolutional theorists. They are like Christian evangelists who cannot fathom other possible realities and motives except theirs. They are so single-minded that it is truly fascinating to watch them explain all phenomena through their lens.

The team behind QI presents without a hint of awareness values such as "a distance of 16093 metres from A to B", "a distance of 62 miles from C to D", "about 6.56 feet tall"...

(And yet once told of that scientist who added 1 metre to his measurement of a mountain, because he feared that the too round number resulting from the computation could have been confused with a rough measurement.)

(To the skimmers: when something is 1000 units long, you have to check the underlying precision - whether it is a very rough estimate or the rounding of something like 1000.0862 - and you cannot translate the former retaining fake precision. The distance between London and New York is not 3,417.541 miles, nor 5,632.704 kilometers.)

The standard way to solve this nowadays is to report error measurements, which introductory university physics textbooks teach.

>"(And yet once told of that scientist who added 1 metre to his measurement of a mountain, because he feared that the too round number resulting from the computation could have been confused with a rough measurement.)"

The best way to report the precision is with an error measurement (e.g. ±2 feet). This isn't an academic source, but a news article supports this:

From LiveScience [0]:

"Legend has it that when the team took the average of all of those measurements, they found the mountain was exactly 29,000 feet (8,839 m) tall, Molnar said.

"They didn't expect anybody to believe it, so the story is they added 2 feet [0.6 m], just to make it look more believable," Molnar said.

[...]

"Despite sophisticated gravimeters, complicated equations and fancy tools like global positioning systems, the elevation of Mount Everest is only precise to within a foot or two.

"All of our elevations have an error," Molnar said."

[0] https://www.livescience.com/50691-how-to-measure-mount-evere...

I remember reading in Scientific American (wow, decades ago) an early article on A.I. using a, then new, trained neural network. There was a small comment at the end of the article where the researcher noted that as they "killed" (destroyed somehow?) the neural network, they started seeing early patterns that it had trained on output.

That sounds a lot like the way HAL-9000 regresses to its earliest programming (reciting its "birth" date; singing an old song) when Dave is shutting it down at the end of 2001: A Space Odyssey.

That is a really interesting observation. I couldn't find such an article. I would love to read it.

I'll try to find it.

I've had something like this happen to me, albeit less serious: I was snowboarding, went over a jump poorly, and found myself totally disoriented as I careened through the air. Every single other the I'd found myself flying through the air flashed through my head at unbelievable speed, in an attempt to search for some past experience to leverage wtf I should do. Ultimately I found nothing, made peace with the fact that I was going to slam into the ground, and promptly did so.

So you're saying you've forgotten the most important aspect of learning to fly. After throwing yourself at the ground, you have to miss.

Funny, I thought I'd previously only heard that from an anime series (Demon Slayer). But since I watched every episode of QI I must've heard it there too. Maybe it was just the repeat mention that stuck. In any case I won't give too much credit to something I've heard on QI and/or Demon Slayer. It is a neat, somewhat poetic, idea though.

It might also be a intensity driven effect, I mean, few important moments of your life revolve around important survival information (fond memories, life events etc).. but an oncoming death taps into absolute levels of emotions, which would match the most intense moments of an existence.

That is indeed a convincing argument, and has been portrayed in various contexts, one of which is BBC's Sherlock when ... (oops, spoiler). However, there was no further explanation as to why there is an evolutionary pressure for the brain to do this trick, AFAIK.

> However, there was no further explanation as to why there is an evolutionary pressure for the brain to do this trick, AFAIK.

Umm… yes there is. It’s a survival mechanism. The premise is self evident for improving evolutionary fitness.

What is QI?

It’s a British panel show, formerly hosted by Stephen Fry and now by Sandy Toksvig, where the panelists (most often comedians) are posed questions about science and history which have surprising answers. The name stands for “Quite Interesting,” and it is—along with being a lot of fun. Lots of shorts and full episodes are available on YouTube.

Here is an example: https://youtu.be/44Db0Xt_ykI

Thanks, I didn't know about it

British Comedy Show, pretty good.

A British tv quiz show.

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