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Comment by matco11 | Hacker News Reader

I like this idea, but I am not convinced about how it is applied here.

If they could have made this video a 200 years ago, the population on earth would have been 800mm people, instead of 7.7bn people. Same humans, same planet, but ~10x difference in what our existence implies about population of other forms of life existing out there

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Yes, but it covers that - out of all the possible times to make the video, this one is more probable because the population is higher and there are more professors of statistics with free time on their hands.

I find the other corollary worrying - we're more likely to be existing at a point in time when we are a higher population than any other. In other words, this is likely to be a high point in human population over time, and our future contains less people than now.

That corollary is known as the Doomsday Argument: https://en.wikipedia.org/wiki/Doomsday_argument

The corollary also shows the limitations: you can't actually come up with a real probability for being wrong without knowing other things about this distribution (you can't know how likely you are to be in the most populous time in the history of the human race without knowing the entire past and future history). So the whole argument from statistics holds no water: it depends entirely on other arguments that give a shape to the distribution, and those arguments have their own problems and ways that they can be attacked.

The predictions actually won't change at all!

None of the predictions in the article actually use # of humans as a data point.

You aren't gonna input 800m to a calculation and get any different result - no calculation uses that number.

The author uses all species of earth to estimate a species size - population density ratio. This works if you remove humans from the equation.

The only other data point specific to humans is our weight.

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