Being alive today: the most improbable coincidence?



Think about it; modern humans have been around for at least a couple hundred thousand years.

Yet, your mind, your soul, your very awareness, happens to be "alive" today. If time is a flow, moving forward, and there's really only "now", isn't it an almost impossible coincidence that your lifespan of 70-90 years happens to occur "now"? Why not a hundred years ago? Why not tens of thousands of years ago? Why not a thousand years into the future? No.... Your mind and body are alive today, in the present - the only valid "now".

To me that sounds like too much of a coincidence. In fact, if you take the number of 300,000 years that modern humans have existed, and we take (just for the sake of making this calculation easily understandable) a lifespan of 100 years, your lifespan could have started at any time during those 300,000 years. There's only a chance of 1 in 3000 (0.033%) that the start of your lifespan would coincide with the present. If we add to this a potential/possible 100,000 years of additional "future time" that mankind may have left, then it's even more of a coincidence: 1 in 4000 or a 0.025% chance.

What are your thoughts and ideas about this? Is there some kind of known paradox about this? Or an explanation?

This questions has driven me nuts for years and years. I just can't wrap my head around it.


Wow, what a huge amount of responses, thank you all so much. Your answers definitely feed my hunger to try and learn more about the subject.

Just as a general reply; most, if not all of you, seem to focus your response around the probability of me being alive today, and assign the probability of 1 to this; after all, if I'm able to ask this question now, it means I must be alive now.

However, what I'm (even) more interested in, is the coincidence of me being alive today, assuming that time acts like an objective spotlight (gradually passing along, moving into the future) shining at one specific point on the timeline (reaching from the moment of the big bang all the way into at least now, or maybe even the future).

This quarrel, again, assumes that time acts like an objective spotlight, which is important, because, when time would act like a subjective spotlight instead, then (in my mind at least) the probability of a person being alive being 1 whenever he/she asks the question would only make sense if time was not a passing, moving spotlight at all - but instead a fixed dimension, meaning that all time (all moments in history and possibly all moments into the future) would exist all at once, and whatever we're experiencing as the present, is just a subjective representation of this specific moment in time... Which is just something I'm having a hard time with comprehending (which doesn't make it any plausible, of course).

I hope this makes any sense.

Again, thanks for all your contributions.


Posted 2018-06-17T09:30:46.113

Reputation: 387

25This is the ultimate example of the Prosecutor's fallacy (see Wiki). Mixing up two kinds of conditional probability. Essentially, from the fact that the probability that a random birth within last thousand years is you is very low, you incorrectly conclude that the probability for you to be born within last thousand years is also low (but it is 1). Pr(you|time) vs Pr(time|you). – ttnphns – 2018-06-17T13:21:39.900

Have you ever had a question why do you even exist? Regardless of time. I think understanding of this is necessary for understanding the answer on this question. – rus9384 – 2018-06-17T14:52:06.920

“Is there some kind of known paradox about this?” Don’t know it’s “real” name, but this is quoted almost verbatim from the Thermonuclear Miracle speech Dr Manhattan gives Laurie on the surface of Mars in Watchmen. 99.999% sure Alan Moore didn’t come up with it all by himself :) – Heroes182 – 2018-06-17T20:28:24.017


Closely related if not an exact match: Doomsday Argument.

– Harry Johnston – 2018-06-18T03:05:23.323

62Throw 20 dice. Write down the numbers. Show them to me. I'll say I don't believe you got those numbers, because the probability of getting exactly those numbers is smaller then winning the lottery several times over. See the problem? – vsz – 2018-06-18T06:16:38.450

3This question is also reminiscent of the "anthropic principle" in cosmology. It seems like an amazing coincidence that the fundamental constants of physics created the conditions that allowed life to form. But if they hadn't, we wouldn't be here to contemplate it. Multiverse theories propose that there are many universes that didn't, and this just happens to be one of the lucky ones. – Barmar – 2018-06-18T19:57:09.587

Religious philosophers use this same argument about the existence of a creator: they attempt to restrospectively compute the odds that all physical constants would be perfectly tuned for life if chosen at random. But they ignore the fact that it's already happened and so the probability is 1. – Fixee – 2018-06-19T20:32:37.240

Some questions, I cannot get the answer to. All I do is try different ways of thinking and seeing what results I get if I perform calculations different ways. It is very possible to pretend the truth is different than it is. For example, sometimes during a dream, I would have a false memory that my past went totally differently than it did. I have 2 distinct definitions of a future, the physical future of our universe and a future of a consciousness. I define a future of a consciousness to be a consciousness that has memories of it or a finite chain of memories of memories that go back to it. – Timothy – 2020-09-29T23:44:03.237

I don't think of it as I will be dead. I think of it as my distant future consciousness doesn't exist. I'm 33. My brain is constantly doing its own thinking independently of my past and burying my past in the sand and because of that, I feel like eons of time have passed and like it better that way. When I recall the past, my recollection of it is a completely different experience than what I was experiencing at the time. According to my conscious perception, my distant past and future don't exist. It's more like I have a book making up a story of my past that doesn't exist. Why I feel like – Timothy – 2020-09-29T23:48:56.160

my future doesn't exist. Because once it comes, I will consider that time to mean my own thinking that I'm doing at that time, not my connection with my prior interpretation of having known it was coming. My memories will get distorted and I will feel like my past didn't happen and that I'm truly conceiving of something new even if I'm not and that I couldn't have possibly conceived of it in advance. All you can do is try different methods of calculation and see what you get. Do you seek a method of calculation that makes it so that those who do exist consciously perceive it. Looking from the – Timothy – 2020-09-29T23:54:22.367

outside, how would you think of it. You would think of it as this is how it's supposed to be done, each person at each time consciously perceiving themself at that time as the absolute present. Do demonstrate the point. The axiom of choice states that for every set of nonempty sets, there is a choice function. It turns out that the axiom of choice is not provable. Take any one set from that set of nonempty sets, now that you already know which one was picked. If you were than told that one element from it got picked, could you derive a contradiction? No. Why do you need to assume that picking – Timothy – 2020-09-29T23:58:49.037

one from that one set must derive from a generalization rather than just from a way of picking one from that set? I will show you cannot derive a contradiction from the negation of the axiom of choice. Suppose that set of sets doesn't have a choice function. Take any choice function on a subset of that set. Then it's a proper subset. Once you're given that subset and the choice function on it, if you were told that somebody picked an element from some of the sets outside that subset, could you derive a contradiction? No. If you take a different function on a proper superset of that subset, it – Timothy – 2020-09-30T00:05:45.293

can include more of those sets in its domain. It's not all of them. It's just more of them. Just because you can't pick one from all of them doesn't mean you can't pick one from more of them. Why must a way of picking one from more of them derive from a way of picking one from all of them rather than just from a way of picking one from those ones. Learn to appreciate how creepy and disturbing it was to even pick ones from some more of them. The original function missed picking some from those sets. However, it turned out that there were some elements in those sets anyway. You just have to – Timothy – 2020-09-30T00:10:28.853

think outside the box and be like "That's the way to look at it." I know there is nothing special about that element instead of another given what that set was and what the choice of picking elements from the original subset was. You have to learn how to take the element itself rather than the set as a given. Does it really matter which one was picked? No. They still picked one and that's good enough already. You have to learn that the question is not whether that element was the one but whether it was an element from that set. The answer is yes. This flexibility is the reason it's the case – Timothy – 2020-09-30T00:15:44.350

that for every set in the original set, there seperately exists a way to pick an element from it. Since that element is one of them, if you take a new partial function based on that element to include one more nonempty set in the domain, you will find that there in fact is a way to pick an element from that one more set after all. That's why there are infinitely many of those nonempty sets. As far as the original function was concerned, you would be saying "Yes, if you take that element when it's given to you on a platter." Suppose you are a God who actually can specifically conceive of all of – Timothy – 2020-09-30T00:22:16.297

members of any of those sets. I don't believe in God myself but that doesn't stop me from thinking of the idea. The part of your awareness on any one of those nonempty sets will think about and study that set from scratch and not just compare it with the other ones and certainly not derive an individual element from a choice function on all of them and derive it just from that choice of picking that element from the one set. You essentially have to focus on just one at a time. You have to learn how to continue doing your own thinking on the spot instead of asking yourself how you would have – Timothy – 2020-09-30T00:28:37.243

done something before. Earlier, you were actually able to think. But now, see for yourself what comes as making sense. Don't blindly ask how you would have done something before. Maybe you will naturally pick up your earlier way of thinking or see for yourself that it makes sense to be like "My past self had feelings. It makes sense to not disappoint it." With my current way of thinking, I think I would not make sense of the argument "Do something a certain way because I would have done it that way before." It's all about thinking what makes sense, not comparing the problem with my own past – Timothy – 2020-09-30T00:36:40.097

way of thinking. I know I have other ways of thinking at other times and have to let myself do things according to my way of thinking at that time when it is that time. It's not worth the struggle. It would create more problems. I'm like a different person at different times. – Timothy – 2020-09-30T00:39:54.780

I didn't notice the notice at the top. – Timothy – 2020-09-30T00:41:44.120



Your reasoning would be sound if you picked any random human who ever lived and checked whether they would be alive today. This chance would indeed be rather low. (Because today's world population is far higher than ever in the past, the chance is not quite as astronomically low as one might think.)

However, we are not looking at any random human who ever lived. You are looking at R_K (note: R_K is OP's screenname) specifically. Thus, the probability of R_K living today is not an unconditional probability over the entire population in a statistical sense. Instead, this is a conditional probability: we are interested in the chance of R_K living today, conditional on R_K posing the question itself - and a fortiori, this implies that R_K is alive today. And of course, the probability of R_K being alive today conditional on R_K being alive today to ask this question is 1.

This is related to the anthropic principle.

Stephan Kolassa

Posted 2018-06-17T09:30:46.113

Reputation: 1 011

36+1 Right on point. There was also an anecdote from Feynman about this, saying something along the lines of "Tonight I was at the movies and I saw a car with license plate 78893. Unbelievable! What are the chances that, out of all the license plates in the world, I would see that one tonight?" – Ant – 2018-06-17T19:21:44.550

Interesting answer! :-) I do understand that the probability that I exist now is 1 because I ask the question myself. That's that - one could say. BUT, that doesn't really, 100% answer my question (if that's even possible, of course). Let's bring in the Moving Spotlight Theory; let's assume this is correct, and that time is a fixed "something", with the past and the present (and possibly the future) existing all together - just what we perceive as "now", is "highlighted" by the spotlight. What a coincidence then, that I am alive exactly now - at the time-span where the spotlight happens to be? – R_K – 2018-06-17T21:06:47.877

10Well, note that your asking your questions necessitates the spotlight being on you. The relevant conditional probability now essentially is "what is the probability of my being in the spotlight, given that I am in the spotlight?" And again, the answer is necessarily 1. – Stephan Kolassa – 2018-06-17T21:27:51.363

3Just to add to what's wrong with your analogy: the "spotlight" is coming from you. In a block theory of time, there is no objective spotlight. Every person sees their own parcel of time as "the special one" because that's the one they're in. So your question becomes, "What the chance that I'm alive during this special time that I am alive (aka, the spotlighted time)." Every person in history could ask that, and the answer is the chance is 100% for all of us. – Chelonian – 2018-06-18T00:59:52.650

2A note on this... 7% of humans (as we know them) to EVER exist are alive today – Cloud – 2018-06-18T07:27:52.723

2What's the meaning of R_K? – FooBar – 2018-06-18T08:32:05.870

15@FooBar: Not sure if that is a deep philosophical question or just that you missed that the OP's name is R_K. ;-) – Chris – 2018-06-18T08:46:22.527

@Ant I do not get it. What is so special about that license plate? – BЈовић – 2018-06-18T10:01:57.127

5@BЈовић Nothing, that's the point. If you go to a movie, you will certainly see some license plate. A priori, it's unlikely that you will see exactly the licence plate 78893 (try going to the movies tonight and check if you see that one!). But you will see something. So a posteriori is not surprising that you saw that license plate, because you would have seen something anyway. Feynman made this point with a joke. As you can see that is the same problem the OP asked about; a priori it's unlikely, a posteriori is certain. – Ant – 2018-06-18T10:10:48.337

1Note that the probability is actually slightly less than 1 because there is some chance that R_K has passed away since posing the question. The actual conditional probability would be P(R_K is alive today | R_K asked a question yesterday). – Challenger5 – 2018-06-19T01:27:56.993

Too add to Cloud's comment, it is estimated there have been ~108 billion humans so far. So the chance of a randomly picked human to live today is actually a lot bigger than one would expect (the ~7% he mentioned isn't really small imho). – kutschkem – 2018-06-19T07:15:42.020

This reminds me of the Boltzman brain idea: the reason why we see such strange things in the universe (paraphrased...) is because only when strange things happen do beings with the ability to notice strangeness exist. And when I say strangeness, I think it's supposed to mean entropy or something. – Faraz Masroor – 2018-06-20T21:42:20.593

1@R_K If you existed 100 years ago in 1918, you would be asking why you exited in 1918 and not 2018. The same could be said about absolutely any time period. What would satisfy you? – Alexander – 2018-06-21T05:06:32.207

@Alexander - The thing is, if we existed in 1918, we wouldn't be alive today, obviously. Yet we are. I'm only saying (and questioning) that, IF time is a constantly moving "something", and the spotlight of time actually IS objective, instead of subjective, then it's still a fair to assume that it's a coincidence that we are alive exactly where the spotlight happens to be. Sure, someone in 1918, or 1818, would have said the same, back then, but he/she is not alive today... I understand the factor of probability 1 (I ask the question so I exist), but that's not really my point (or question). – R_K – 2018-06-22T10:20:25.983

1the spotlight of time I'm not exactly sure about this analogy, but if I understand you correctly, you take the spotlight of time to be that portion of the timeline that you're conscious of? In that case, your existence is what defines the spotlight of time. The fact that your existence perfectly coincides with your idea of the spotlight of time is an absolute certainty, given that it is your existence that gives rise to the spotlight of time. Though I could be completely misunderstanding you, in which case, please correct me and elaborate :) – Alexander – 2018-06-22T16:00:47.863


Shuffle a standard deck of 52 playing cards and look at the arrangement you end up with. Assuming your sorting was completely random the probability of you getting that exact arrangement is about 1 in 8 x 10 ^ 67. What an incredible coincidence! Well not really - you had to end up with one of the possible arrangements and they are all improbable, so an improbable event was guaranteed to happen. Similarly you exist, therefore you have to be alive at some point, and therefore you must be alive at one of the periods of time you could be, even though each is individually unlikely.

It is actually much more likely that a randomly chosen person will be alive now than 10,000 years ago. The world population today is over 7 billion, 10,000 years ago it was something like 5-10 million (Wikipedia).


Posted 2018-06-17T09:30:46.113

Reputation: 531

It is more likely that a random person would be alive now than exactly 10,000 years ago, however it is less likely that a random person would be alive now than 10,000 or more years ago. – Benubird – 2018-06-18T08:44:38.720


@Benubird. Actually, it's both. The Population Reference Bureau extrapolated the world population trends back to prehistory in order to estimate the total number of humans who had ever lived. Their estimate was 108 billion, which suggests that even if we did use the prior probability instead of the conditional probability (which we shouldn't, as user33828 and Stephan Kolassa both point out), there would still be a 7% chance of a uniformly selected human being alive today. (And only about 1.1 billion lived before 8000 BCE.)

– Ray – 2018-06-18T18:02:59.583

2@Ray That's only if you don't count all the people who will be born in the future... – Challenger5 – 2018-06-19T01:29:25.193

@Challenger5 True enough, as far as the 7% value goes. But the size of the current population relative to that of 8000 BCE would be remain unaffected by the future population growth. (Everyone knows that all the cool time travelers prefer 3000 BCE. :-) ) – Ray – 2018-06-19T06:02:24.020

@Challenger5 And in turn, that is only if you assume that there will in fact be a significant number of people born in the future. – JBentley – 2018-06-19T12:11:47.523

@JBentley There is an overwhelmingly small but nonzero probability that quantum effects will cause a pregnant mother to materialize from nowhere in an environment friendly enough to have time to give birth. Since it is likely that the universe will last forever in a big freeze, it seems certain that, indeed, an infinite number of people will be born in the future, even humans go extinct and civilization dies out.

– Challenger5 – 2018-06-20T02:04:49.527

@Challenger5 You're so optimistic that we're going to last more than a few generations. It's entirely possible that the reason we can't find any intelligent life in the universe is once they have a certain amount of energy they can't control it and blow themselves to smithereens. – corsiKa – 2018-06-20T19:45:42.083

@Challenger5 I would be very careful making that sort of argument. It involves both infinities and quantum mechanics, both fields in which it is extremely easy and common for laymen to make mistakes due to careless reasoning. It is true that if there exists an infinite amount of time over which there is a nonzero probability of that specific scenario happening, then it will Almost Certainly happen an arbitrarily large number of times. Although there exists an infinitesimal chance of it not happening, and I can't say how that would interact with the infinity without the actual equations. – Ray – 2018-06-20T20:35:39.320

... Another thing that must be considered is that there would also exist nonzero probabilities of other things, like new big bangs, and we would need to consider how the relative probabilities of all of them interact. If there are an infinite number of alternate scenarios that would prevent yours from happening, things get tricky. I don't have anywhere near the expertise in quantum mechanics to go into more detail on that. Finally, the long term cosmology predictions that give us the infinity in the first place are nowhere near certain. If the infinity goes away, the whole argument falls apart – Ray – 2018-06-20T20:35:49.267

1Fun fact: any good randomly shuffled poker hand is more rare than a Royal Flush. There are 4 combinations of cards that classify as a Royal Flush, but only a single combination that equals your hand. – Alexander – 2018-06-21T05:08:48.490


The first time I recall encountering this argument was in Alan Moore’s Watchmen, where the probability of what you describe is likened to “events with odds so astronomical they’re effectively impossible, like oxygen spontaneously becoming gold”.

I find the argument similar to the gambler’s fallacy. An example:

In a fair coin toss, the probability of landing on heads (or tails) is 50%. Before we start tossing the coin, how likely do you think it is that the coin will land 20 consecutive times on heads? As you’d expect, they are astronomically low. Also as expected, while making the calculations every consecutive toss we add lowers the probability — landing 10 consecutive heads is less likely than landing on it twice.

But now let’s say we’ve already made 19 tosses that all landed heads. What’s the probability the next toss will also land on heads? The gambler’s fallacy is thinking the previous math applies and the odds are astronomically low. They are not — they are once again 50%. This is because the coin doesn’t care how many times it landed on the same side. It’s not self aware and won’t try to “correct” itself to (what we call) a fair/balanced result. Every toss is statistically independent from another, individually they all are 50/50. Looking at past tosses gives us no information of future results. Statistics apply when the tosses we want to predict are all in the future.

The same happens here.

If centuries ago one asked “what’s the probability of the specific person R_K being alive on the specific time of June 17 2018”, the odds might indeed be astronomically low. But no one asked that question, so the fact you’re alive at this moment is as (ir)relevant as you being alive at any other point in history. They’re all as probable as you having never existed in the first place. If you (or me, or anyone else) had not existed, no one would have known or cared. You are a person, some person, not the specific person someone else was predicting or waiting to exist in a point in time.


Posted 2018-06-17T09:30:46.113

Reputation: 231


The probability of an event X happening, GIVEN THAT IT HAS HAPPENED, is always 100%.

I hear thinking like you give used in many flawed arguments. For example, I once got into a conversation with someone who claimed that the Gospels in the Bible must be frauds, because the people who it is claimed wrote them would have been like 70 years old at the time they were written, and very few people in those days lived to be 70. So if the probability of someone living to be 70 was 20 to 1, then the odds are 20 to 1 that this person could never have written this book. Except, umm, while FEW people in those days lived to be 70, SOME did. Obviously the ones who didn't live to be 70 couldn't have written this book. But no one is saying that he did. We're saying that it was written by someone who DID live to be old. (This doesn't prove that the Bible is true, of course, and that's not my point in this discussion. Just that this particular argument is flawed.)

Look at it this way. The odds against winning the lottery are like 20 million to 1. (Depending on which lottery.) So if you read in the newspaper that Fred Smith won the lottery yesterday, would you say that this story is virtually impossible because the odds against Fred Smith winning were 20 million to 1? No, because we are asking for the probability that Fred Smith will win, GIVEN that he won. That probability is 100%. If you asked me the day before the winning number was chosen what the odds are that Fred Smith will win, I'd say 20 million to 1. But once the numbers are chosen and we see that they match the numbers on Fred Smith's ticket, the odds aren't 20 million to 1 any more. They are now 100%.

Likewise, if you had some master list of all the human beings who have ever lived, and you picked one at random and asked, What is the probability that this person would be alive in 2018?, depending on what estimates you're going to use for world population over history etc, I'd say the odds are pretty strongly against. But if you take a list of people who are alive today, and ask what the odds are that they are alive today, while clearly that's 100%, because we're picking from a pool of people whom we already know are alive today.


Posted 2018-06-17T09:30:46.113

Reputation: 259

5This answer is preposterously unlikely. But my comment is just as unlikely. – Wildcard – 2018-06-18T20:22:51.327

@Wildcard Exactly! What is the probability that someone randomly bashing keys on a keyboard would come up with exactly this combination of letters? I haven't bothered to calculate, but probably quadrillions to 1 or more. And yet ... there it is. – Jay – 2018-06-19T17:58:28.473


A couple of brief pointers on how to think about this:

First, in your question you are assuming that the passage of time is an objective feature of reality. That is, in order to give a full description of the world, you need (perhaps) to describe what occupies every point in spacetime, but that's not enough: you also need to provide a concrete location for the objective now. This is a variety of what is known as the A-theory of time. Most philosophers and physicists, on the other hand, endorse a B-theory of time, according to which the passage of time is subjective: for every inhabitant of spacetime, their time is "now". The paradox that worries you does not arise if the B-theory is correct.

And, second, your argument depends on what is known as self-locating beliefs: beliefs about where (or when) one is. Reasoning involving self-locating beliefs is notoriously slippery. One illustration of ways in which they may lead us astray is the Sleeping Beauty problem.


Posted 2018-06-17T09:30:46.113

Reputation: 2 434

2I'm not seeing the connection to the SB problem? – Cloud – 2018-06-18T07:32:27.273


Right now I am looking at a pair of scissors laying on my desk. What are the chances of that?!?? Think about it: that pair of scissors had to be created; the desk had to be created. The house that this is all in had to be created. What are the chances a house was built right at the location it has been? And that a desk was brought in, standing in the location that it is in. And that a pair of scissors would be laying on that desk, laying in the position that it is in ... all exactly on June 17, 2018?!? From this perspective, it is an absolute miracle that I am indeed looking at a pair of scissors right now! Indeed, for pretty much every truth with any kind of detail, it is a complete and utter miracle that that truth came to be!

OK, so then does that mean anything? No. It is all just a complete fluke. I guess that is how you should think about it. Just like we don't (and of course shouldn't!) get all bent out of sorts because we see a pair of scissors laying on a desk in front of us, you also should not read anything into the fact that you and I are here. We're here because it's all just a fluke.


Posted 2018-06-17T09:30:46.113

Reputation: 2 677

+1 because scissors example opens up the existential (not mathematical) dimension of the question. If the scissors were like one of stars on that black sky canvas one might indeed feel lost and anxious facing them (like facing all those thousands of lives in history before us). Because stars are difficult grasping as useful, adjutant. With them, we are, most of the time, futile too. But these scissors on my table in front of me is likely to bear the mark of usefulness, they are in labour under the sun. Most of the time I don't reflect on that they are randomly chosen from the many ones. – ttnphns – 2018-06-17T18:23:09.417

2Not only that, but a society has to be formed with a language that calls one object a pair of scissors! – pipe – 2018-06-17T18:51:05.563

1This borders on nihilistic, it is indeed a miracle that you are reading this comment :) – Cloud – 2018-06-18T07:36:17.157

2@Cloud Well, given that you posted it under my Answer, not so much. But the fact that I am reading it this very second is :) – Bram28 – 2018-06-18T11:55:39.203

1A fluke? Hardly. No naturalistic explanation for existence is credible. The only credible explanation is the existence of God, but many people, philosophers or not, don't like to go there. – Ham Sandwich – 2018-06-20T22:51:02.627

Plot twist: those are your father's brother's nephew's cousin's former roommate's scissors. – Mazura – 2018-06-21T03:06:46.940


Dead or unborn people don't ask themselves : "Why am I not alive today?".

By contraposition, you've got your answer:

You can ask yourself the above question, it means you're alive.

Eric Duminil

Posted 2018-06-17T09:30:46.113

Reputation: 974

1But he can't prove he actually exists though. lol. – Mohammed Joraid – 2018-06-19T22:46:20.373

2@MJoraid He can't prove to you that he actually exists (though he can provide evidence that should put it beyond reasonable doubt), but everyone can prove to themselves that they themselves exist by questioning whether or not you exist, because the fact that you are able to question your own existence means you exist in some fashion (you might still be wrong about the nature of your existence though). – Cubic – 2018-06-20T10:57:09.000


Your question is, why does your lifespan occur now rather than at some other time? But if it did occur at another time, then that would be your "now" and you would be asking the same question. Sometimes I get myself wrapped around the question "Why am I me and not someone else?" But of course the answer is that if I were someone else, then that would be my "me". The probability that you are alive at some specific time is low. But "now" is relative to your own consciousness, so asking why you are conscious "now" is a tautology.


Posted 2018-06-17T09:30:46.113

Reputation: 41

Do you have any references to strengthen your answer perhaps of philosophers who have discussed this issue and came to a similar conclusion as you did? This would give a reader somewhere to go for more information. – Frank Hubeny – 2018-06-18T20:31:52.763

2Sorry, I am not well-read enough in philosophy to give a reference. Others here have shown that by using conditional probabilities the probability of the original question is 1 and not a very small number. I was trying to come at it from a language/logic approach to show that the probability is 1 by definition. Proposition: The definition of "Now" is the moment in time when your consciousness is aware and forming questions and inferences. Given: You are conscious and forming a question. Inference: Therefore it is "now". – JGH – 2018-06-18T21:36:27.067


A reason why you might find it surprising/improbable, is having a view that you (i.e. "your mind, your soul, your very awareness", and your body) is a self that's independent of its present circumstances -- so you're remarking on an allegedly improbable coicidence between this self and its location.

A different view suggests that this self is a product of (it is conditioned by) its environment -- it's not unique (thus not identifiable), among the set of human beings for example, except as a product of its environment (including its genes, society, education, food, possessions, past actions, etc.).

For example, look at a house in Paris and say, "Isn't it remarkable that that house is in Paris!"; one might reply, "No, it's the fact that it's in Paris that defines it, it has no existence independent of its location in Paris: it's by looking in Paris that you found it; and Paris made that house what it is."

To think that the house has an existence that's independent of Paris would be a kind of a "conceit".

One shouldn't privilege the view of Paris either: it's no more existent than its houses -- it's merely an aggregate of components.

Perhaps this explanation corresponds to the Buddhist view of anatta or anatman (i.e. "without self" or "no thing should be seen as an independent soul"), and sunyata (i.e. "no thing has its own independent existence").

Even "very awareness" (of anything) is conditioned by contact with the thing (or idea) it's aware of.


Posted 2018-06-17T09:30:46.113

Reputation: 611


If you want to go even deeper into the formation of an embryo, millions of sperm are released each time someone ejaculates. Let's take this number as 400 million (400,000,000).Source The average human male ejaculates 7500 Source times in his life time.

400,000,000 * 7500 = 3,000,000,000,000 (3 trillion sperm)

Add this variable to your thinking. The odds become even less likely.

Just because the odds are less likely doesn't mean it could never happen. It could happen, because you are here.


Posted 2018-06-17T09:30:46.113

Reputation: 31

It would be good to provide references for the number of sperm and ejaculations just in case someone questions them. It would strengthen the answer. – Frank Hubeny – 2018-06-17T13:10:10.173

I made an edit for grammar and corrected the calculation. You are welcome to roll this back or continue editing if you wish. – Frank Hubeny – 2018-06-17T13:18:26.967

1400,000,000 sperm? This is in odds with the info I have. In either way this does not provide an answer but only forces the question. – rus9384 – 2018-06-17T14:35:04.527

Only 7,500 times? For an 80 year life that's once every 3.9 days... did you get this data from monks? xD – Cloud – 2018-06-18T07:38:09.703

2@cloud That is an impressive 80 year old who has been ejaculating at a consistent rate from the moment he was born until the day he goes into the grave! In reality the rate is actually zero for the first decade (ish), probably peaks somewhere in the teens/20s, and then declines over the remainder of the lifespan. Add to that the fact that it's an average (so we're including less sexually active people in the numbers), and it doesn't sound so unreasonable. – JBentley – 2018-06-19T12:12:58.873

@Cloud Fixing the average of 7500, so every time one masturbates, he is taking away one good future ejaculate. – Mohammed Joraid – 2018-06-19T22:49:26.957


The question is essentially, "I am alive right now, and I am alive at the exact same time that I am alive. Isn't that impossibly unlikely?" No, it's a tautology. It's the same as saying "Isn't it impossibly unlikely that the current room's temperature is equal to the current room's temperature?" Nope, it's 100% guaranteed, because it is a tautology. "What are the odds that Super Bowl X would be held on the exact same day as Super Bowl X?" 100%. That's not a coincidence, because it is the exact same event repeated twice. It isn't a COincidence at all if the two events are not at least distinct (and also possibly unrelated, depending on how the problem is worded).

If you randomly selected a person born in all of Earth's history, without any sort of selection bias that might prefer or guarantee a person who is currently living, then it would be remarkably coincidental that they were born on the same day as you. But it is not a coincidence that a particular person is alive at the same time as a particular observer, who also is that same person by design.


Posted 2018-06-17T09:30:46.113

Reputation: 21

It seems like there must be more to this question, but expressing what that is may be difficult. – Frank Hubeny – 2018-06-18T23:21:51.817

How does this add anything that hasn't already been written in other answers? – Philip Klöcking – 2018-06-20T10:24:25.027

It's shorter and to the point, which it hammers home; that this has nothing to do with philosophy and everything to do with logic. And it contains the words tautology and selection bias - it's no wonder there's a 'coincidence' if you're guilty of either of the former. We don't really need the anthropic principle; just an axiom: it wouldn't be if it wasn't. and no one knows why IT is - so stop asking ;) – Mazura – 2018-06-21T03:41:41.203


Causation punctures the paradox of coincidence

You take into account only two, apparently unrelated, things : (1) your being alive and (2) time t1 (now). Given data as bare as this, there is a coincidence and even if you like an improbable coincidence between (1) and (2). But isn't there a causal link betweeen the two ? You are alive now as the latest state of affairs in a causal chain which connects you to your past. Keeping the biology simple, let's say that you are alive now and not 200 years hence or 200 years in the past because of (if I may put it so) a causal interaction between two persons that resulted in your conception and existence. You are alive now because of a precisely datable causal interaction that occurred in the past (t minus-1). Equally the two persons whose causal interaction at t minus-1 resulted in your conception and existence were themselves each the result of causal interactions that occurred at times t minus-2 and t minus-3 (unless the respective causal interactions that resulted in their conception and existence were simultaneous). Causal interactions are datable. Where's 'the most improbable coincidence' in (1) your being alive now and (2) time t1 (now) ? The improbable thing, given the causal nexus, would be if you were not alive now rather than at some arbitarily different time.

Geoffrey Thomas

Posted 2018-06-17T09:30:46.113

Reputation: 34 276


Due to total human population being the largest its ever been its more probable that a human being would live now than at any previous time in human history. The world's current human population is over 7.6 billion people and this is expected to reach over 11.2 billion by the end of the Century. World Population Growth

Historically total human population was far less than this. An estimate during medieval times is a total of around 0.35 billion in 1400 AD. In prehistory humans numbered far less than this. An estimate at the time of Ancient Egypt is 100 million. So this is approx 1% of a 10 billion figure we can expect to see this Century. Therefore the chances of existing at the time of Ancient Egypt would be about 1% of how likely it would be toward the end of this Century. Historic world population estimated

A human population bottleneck occurred as recently as 70,000 years ago. At this time the total number of humans alive dropped to as low as 1,000 to 10,000 individuals. This explains why genetic studies show a lot of relatedness between people who are geographically very distant. Being a human alive when there were the least humans on the planet would be the most improbable time to exist.


Posted 2018-06-17T09:30:46.113

Reputation: 1

This is a nice distributional analysis but has nothing to with the "probability" of being alive today. Probability is an estimator for future events. You are talking about absolute frequency. Probability is derived from the frequency of events already happened (and counted), but not the same. Also, there is no such thing as "material probability", i.e. the probability of anything that is isn't defined. The event "you are one of the humans living today" has no probability. The event "choosing exactly one out of the humans alive today, that one is you" has one. Until you did the choosing. – Philip Klöcking – 2018-06-20T10:30:09.320

I think you're actually agreeing with the analysis but you don't like the conclusion. The chance of an object being in existence is directly related to the volume of things that exist. ie. If there were a total of 100 billion people (estimated purely for arguments sake) that ever existed and 20 billion people lived in the 20th and 21st Century then the chance that a human being existed in those Centuries would be 20% that's just basic mathematics. It'd like looking at a bell curve and realizing that the majority of people fit in the big bulge of the curve and very few out by the thin edges. – Stevernator – 2018-06-20T23:16:39.153

"Due to total human population being the largest it's ever been, it's more probable that a human being would live now than at any previous time in human history." — Extrapolating the probability distribution in both directions leads to an even more disagreeable conclusion: if there were really going to be even more billions of people on Earth two centuries from now, wouldn't you expect to be one of those people instead of one of us? This is known as the Doomsday Argument.

– Quuxplusone – 2018-06-22T01:34:40.927


I just farted two seconds ago.

What an incredible coincidence! Out of all the possible times in my lifetime (and after death, by the way) I could let out a three-point-six-two-second fart -- and that's such a precise number there are only a handful of times I can let out that specific fart -- what's the probability of it having been precisely two seconds ago?

Being surprised has nothing to do with a low probability. The probability of almost any event (specified to fullest detail) occurring is zero. So what? Our surprise has more to do with the kind of event that occurred -- e.g. meeting a person with blue skin is more surprising than meeting a person with a very specific shade of brown (even though the first may very well be more likely), and a fart of length 3.14 seconds is much more surprising than a fart of 3.65 seconds.

To answer your question -- so what?


Posted 2018-06-17T09:30:46.113

Reputation: 161


I’m adding another answer instead of editing my current one since I’ll be responding to your edits and not the original question.

Just as a general reply; most, if not all of you, seem to focus your response around the probability of me being alive today, and assign the probability of 1 to this; after all, if I'm able to ask this question now, it means I must be alive now.

To be fair, you specifically referenced the probability of the event. It’s both in your title (“the most improbable coincidence?”) and text (“only a chance of 1 in 3000 (0.033%)”).

However, what I'm (even) more interested in, is the coincidence of me being alive today

Merriam-Webster defines coincidence as “the occurrence of events that happen at the same time by accident but seem to have some connection”. Events. Plural. You being alive today is a single event, so there’s no inherent coincidence in that. It’s the same as saying “I’m holding an apple”. Single event, no coincidence.

The only way you being alive today could be considered a coincidence would be if there were another unrelated event that seemed to have some relation to your current existence. As stated previously, if no one predicted your existence before it occurred, there is no coincidence to you being alive now, as it’s as likely as you being alive at any other point or not at all. And as others have stated, if we ask about you being alive during/after the fact, then the probability is 1 because we already know the event is true.

assuming that time acts like an objective spotlight (gradually passing along, moving into the future) shining at one specific point on the timeline (reaching from the moment of the big bang all the way into at least now, or maybe even the future).

The given answers were already compatible with that scenario. It doesn’t matter where the spotlight currently is, since questions can be made about any point in time but only in the point in time the spotlight is shinning on. If the spotlight is not on you, there’s no way to ask anything. Previous reasonings still apply.


Posted 2018-06-17T09:30:46.113

Reputation: 231