## probability of being alive

Discussions concerned with knowledge of measurement, properties, and relations quantities, theoretical or applied.

### probability of being alive

This thought isn't thought through but maybe someone can add some insight into it. Or maybe I will gain insight into it just by typing out my thought.

Thinking about the exponential rate of human population growth.
At some point there has to be a crash because resources can't support it.
Of course human consciousness and innovation always messes up these calculations or predictions but...

Looking at the time span of human existence from the beginning to the end (assuming that it will end at some point), the probability of being born during the peak of human civilization seems like it would be the greatest at or near the peak of human civilization. In other words, there is far less of chance of being one of the early humans back when there were only several thousand in existence at one point in time in the past compared to 7.3 billion at the point in time right now.

If this is true, it would seem like the probability that we are all living right now near the peak of human civilization is greatest. So does that mean there is a high probability that we will see it crash in our lifetime? Or does it just mean that with each generation there is a higher probability of them seeing the peak of human civilization? Since we do not know where the future peak is, can we at least say it certain that we can say that there is a higher probability of us seeing it crash than any generation before us?

My brief thought and feeling when having this idea was just that it seems like being born into the world right now has a pretty good chance of seeing the height of human civilization because it seems more rare that I would have been born into a time in the past when things were progressing much slower and the population was much lower. This brings in another part of this equation... The exponential growth rate of technology advancement. I don't know if they correlate exactly but technology advancement rate and population growth rate would probably line up pretty well. They might be a bit more choppy in the past when certain individual scientists leaped us forward but they are probably smoothing out and matching up better as more people are developing technology in collaborations.

Perhaps if we combine the two plots we could see that they feed off of one another. That is an advancement of technology creates a spurt of population growth (like penicillin) and as the two curves smooth and match one another it will sky rocket into a crash. It is my feeling right now with this thought that given the higher probability than ever before of being born during the height of human civilization I could have an unfounded fear that it will peak and crash in my lifetime.

zetreque
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### Re: probability of being alive

Rare, as compared to what? Isn't probability a statistical ratio between a phenomenon and an absolute number of repetitions of the same event. So, if you drop a slice of toast 20 times (100%), it should land jam side up 10 times (50% - on average... regardless of the price of the carpet). If you drop it 500 times, that's your 100% and the 250 jam-side-up landings is the 50% probability.
But it will land, on one side or the other, 100% of the time.

The probability of each individual human existing is 100% - whenever in history they were born, however many of them there are at a given moment. To make it a true probability calculation, you'd have to put in some other factor. Like, how many conceptions result in a live birth, or how many babies are male or female, as a percent of the absolute number that has actually occurred.

Whether we've reached the maximum carrying capacity of the planet is a completely separate question.
(Yes, very nearly.)
Serpent
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### Re: probability of being alive

The greater the population, the more births and the higher chance you are among those births. And I conveniently left out the greater infant mortality long ago.

I did define this scenario as there being an end to the human species so we know n births.

zetreque
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### Re: probability of being alive

zetreque » May 15th, 2018, 10:12 am wrote:The greater the population, the more births and the higher chance you are among those births.

No. If the the total population were eleven, you and I would be 100% guaranteed to be among them. If the population were 50 billion, you and I would be 100% guaranteed to be among them. (If the population were one, I would be 100% guaranteed to be it, and I'd be talking to a figment of my own imagination, or someone who disintegrated while I was typing this.)
Since we do exist, our probability of having been born is exactly 100%. The same as everyone else who exists.

The probability of more people being born grows with the population (all else being equal - in actual fact, the birth rate does fluctuate with various environmental and cultural influences); the probability of each individual remains the same: 100%, even while each individual becomes a smaller percent of the total population.

I did define this scenario as there being an end to the human species so we know n births.

I don't understand that part.
I see that there is a physical limit to growth: either we stop overreproducing or we run out of resources and die. (Again, all other things being equal: the asteroid passes at a safe distance; the volcanoes take turns erupting, etc.) If that limit is to be reached within the next 50 years, you have a far greater chance of seeing the end than I do: your life expectancy is longer.
Serpent
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### Re: probability of being alive

I wasn't' talking about the possibility of being born, I was talking about the time when we are born and the probability of it being associate at the time of peak

If 100 humans were born and 80 were born at the middle of a bell curve or at the top of an exponential curve, your chance of being born at the middle or top is greater than being born as one of the first or last (outliers).

zetreque
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### Re: probability of being alive

The problem, as Serpent addressed, is a confusion between statistical probability and your own personal probability. It's two different domains. Your odds of being born in the 20th century are p = 1.0. Or, in common parlance, 100%.

Otherwise, I could make my own existence highly improbable. Of the 100 billion-plus humans who have ever lived, ony an infinitesimal fraction have been left-handed males of Irish, Norwegian, and English descent who can roll their tongue into a tube shape and have an overbite.

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### Re: probability of being alive

So you are saying that if the above graph represented the beginning of the species at 1920 and the end of the species at 2010, or just your population size, then you wouldn't have a higher chance of being one of the births around 2010 than around 1935?

Seems to me the probability of being a birth at 2010 is 300,000/total
and the probability at 1935 is 100,000/total

zetreque
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### Re: probability of being alive

If you take the total number of people that have ever lived (if you could get that information) and divide by the number born in each year since the first human (if you could pinpoint the year a hominid made gave birth to a verifiable human) then the odds of any one unspecified human being born in a particular year would vary, and the numbers would generally grow as you approached the present.
As general trend - not a smooth curve.

There are more people alive now than there have ever been before.
On the other hand, there were more people alive before the last ice age than afterwards, and there were more people before the Black Plague than after, more before WWII than after - and we've made up and surpassed the numbers in the generations following each event.
But there is nothing to say we won't have another sudden catastrophic diminution of population without actual extinction, and no way to predict what will follow. Afterward, the numbers may increase again, or keep declining, or remain stable for an indefinite period, depending on the circumstances.

Why complicate it with probability?
Last edited by Serpent on May 15th, 2018, 3:19 pm, edited 1 time in total.
Serpent
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### Re: probability of being alive

Just a thought experiment because then if you look at something like this curve it...

Seems like there is a greater chance of being one of those alive today than at some point in the past.

zetreque
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### Re: probability of being alive

Yes, there was a sudden upsurge due to the Industrial Revolution, without a balancing decline in religious power. All you're still saying is that there was a sudden, world-wide drop in early mortality and corresponding rise in fertility. That's not a probability, that's a known fact: it's already happened.
The graph ends before the next millennium.
Probably, all those people will make more people. Probably, there will be even more people before the event that brings it all crashing down.

Yes, if you calculated the odds of each person who ever lived being alive in any given period, now would have the highest probability.
I guess what I don't grasp is the significance.
Serpent
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### Re: probability of being alive

If you are defining the peak of civilization as the time at which the most humans are alive at a given moment, than are you really just asking if whether we think we will see a population crises in our lifetime?

SciameriKen
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### Re: probability of being alive

I think that is one way of defining the peak of civilization since it takes teams of people and collaborations to do and discover things these days (and larger teams, collaborations, and more individual researchers lead to more discoveries or potential catalysts for a crash) and yes I am asking/saying that it seems like each step up in population seems like there is a greater chance of some crash happening. Since there are more people alive than ever before it "feels" like we could see a crash in our life time.

zetreque
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### Re: probability of being alive

If we think on the 2nd law of thermodynamics, we see that in a closed system unhindered growth leads to extinction due to diminishing resources and increasing entropy. It's an unsustainable situation but people don't seem to care 'cos they're doing fine. It's a selfish and short-sighted view.
Probability of being alive is 100%. Life is proven. 100% probability equates to certainty. But this is only valid if potential and conditions exist in the right place at the right time.

Event Horizon
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### Re: probability of being alive

I get that probability of being alive is 100% but I'm talking about the probability of being alive at a certain time being a percentage of the whole population.

If you have two years
2010 and 2011 and it was fixed that one person was born in 2010 and 9 people were born in 2011 no matter what.
Represent marbles if you will for each person to fill one of the spots. You are one of those 10 marbles.
You take the same 10 marbles and randomly fill in the spots over and over again. You will most likely end up being a marble in 2011

zetreque
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### Re: probability of being alive

If you assume the same conditions for each of the two years, there is no reason for one year to be more fruitful than the next. If you repeated the experiment 100 times, you can expect anomalies to get fewer as a percentage and you should arrive at a 50-50 result with the odd outlying results with a confidence level of about 95% statistically. Not unlike flipping a coin really. Unless I've misunderstood something.

Event Horizon
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### Re: probability of being alive

There was one person born in 2010 and 9 born in 2011 and 10 total. It's a fact. It's history. Written in stone. You can't go back and change that.

zetreque
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### Re: probability of being alive

Hmm. Actually, I think the issue is that two consecutive years won't be significantly different enough to produce very informative results. If you ask the same question of years 100 years apart there are many other factors that come in to play and you might well find your chances to exist are significantly different.

Event Horizon
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### Re: probability of being alive

My above example. 1935 vs 2010

300,000/~18.4billion in 2010 = 1.36%
110,000/~18.4billion in 1935 = .6% (not paying attention to significant figures)

zetreque
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### Re: probability of being alive

Is it not just a case that an elevated population is liable to produce more progeny so long as resources allow? It's many long years since I used Stats on a regular basis. I don't mean to be a pain.

Event Horizon
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### Re: probability of being alive

Event Horizon » Wed May 16, 2018 11:38 am wrote:Is it not just a case that an elevated population is liable to produce more progeny so long as resources allow? It's many long years since I used Stats on a regular basis. I don't mean to be a pain.

right. My oversimplified point was that the more people there are, the more available spots there are for births and it seems like there is the highest probability of being born during a time when the most humans exist. Then I threw in some oversimplified guesses that the year/s that the most humans exist are likely to be the year/s in which have the most instability or greatest over-demand of resources and maybe the greatest achievement.

zetreque
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### Re: probability of being alive

I see your point. But what you will likely see is that as resources become harder to access, the exponential growth model will slow down and eventually decline. During the 'boom' years before we get to that, many more people are likely to be born. Later as resources dwindle, less people will be able to support new births, and as resources diminish, conflict over resources and the actual lack of resources will force a decline.
This means that in a closed system there will be an optimal time to exist, but how to define when that time is will be pretty tricky to pin down I think.

Event Horizon
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### Re: probability of being alive

Obviously we can't predict the future or the efficiency at which we can use resources when human consciousness and innovation are involved. The optimistic view is that it will be a nice peaceful slow down as population stabilizes and knowledge/intelligence catches up with technological power. The pessimistic view is that human greed/arrogance is too out of control and will cause a major collapse by not planning ahead or being smart enough to look out for an upset in life sustaining systems. Then you have anywhere in between.

zetreque
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### Re: probability of being alive

I'm rather pessimistic that we will shepherd our resources sustainably. Switching to an agrarian model might help delay our decline which, I'm sorry to say, seems inevitable. People are greedy, they are selfish and worst of all they are ignorant. (Pls excuse the terrible generalisation). But it is what it is. We are lucky to live in our time, I wouldn't want to be here 'ere the end comes. And it will come. But that my friend is a whole other discussion.

Event Horizon
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### Re: probability of being alive

This question/analysis is founded on these premises...

1. That you are born into a particular time, place and circumstance by chance.
2. That you could have been born into a different time, place and circumstance.
3. That who you are is something previous to the time, place and circumstance of your birth.

These are premises which I reject as incorrect. Instead I believe the following.

1. Who you are comes AFTER the time, place and circumstance of your birth. Basic existentialist maxim: existence precedes essence.
2. This doesn't mean that the time, place and circumstance define you, but these do present you with the choices you have in life, and these choices do define you.
3. But these choices are not predetermined by either the circumstances OR some pre-existing nature or personality. Existentialism tends to support Libertarianism and certainly does not preclude it.
4. Thus you could NOT have been born into a different place and circumstance.
5. If you could calculate the probability of such circumstances having come about then this might be a probability that you ever would have existed at all. But given that you do exist, the probability of you existing now rather than some other time is 100%.

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