# So there exists another world with someone like me in it? **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [October 30, 2006, 4:11am UTC](https://boards.straightdope.com/t/so-there-exists-another-world-with-someone-like-me-in-it/378404 "2006-10-30T04:11:26Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [October 30, 2006, 9:44pm UTC](https://boards.straightdope.com/t/so-there-exists-another-world-with-someone-like-me-in-it/378404/21 "2006-10-30T21:44:22Z")
> [@](#): > > Still, I think that a person could make a fairly compelling argument that a world existing that is identical to earth is a possible configuration in the universe that we’re in. As I say above, only if you qualify that with “,…but _extremely_ unlikely…” And realize that “extremely unlikely” here means “virtually zero probability” ---
**Author:** ![begbert2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/begbert2/32/3357_2.png) [@begbert2](https://boards.straightdope.com/u/begbert2)\ **Post date:** [October 30, 2006, 10:27pm UTC](https://boards.straightdope.com/t/so-there-exists-another-world-with-someone-like-me-in-it/378404/22 "2006-10-30T22:27:05Z")
[QUOTE=CalMeacham] As I say above, only if you qualify that with “,…but _extremely_ unlikely…” And realize that “extremely unlikely” here means “virtually zero probability” [/QUOTE] Well, of _course_ it’s extremely improbable. (Not that my sentence wasn’t equally true without the qualification, mind you.) But I was specifically answering an argument that was arguing that some things are simply impossible, with the goal seeming to be to reduce belief in the posibility of ‘clone planets’. The problem with that is, of course, that the earth as it is _has_ happened once, and therefore it’s not impossible that it could happen again. Vanishingly unlikely, but certainly more likely than something impossible. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [October 30, 2006, 10:36pm UTC](https://boards.straightdope.com/t/so-there-exists-another-world-with-someone-like-me-in-it/378404/23 "2006-10-30T22:36:48Z")
> [@](#): > > The problem with that is, of course, that the earth as it is has happened once, and therefore it’s not impossible that it could happen again. Vanishingly unlikely, but certainly more likely than something impossible. It depends on what you mean by “identical to earth”. If you mean about the same size and composition then it’s trivial. Even if you mean similar makeup down to water and even having life, I’ll give you good odds. If you mean that it looks like a virtual clone of Earth, down to the same continents, the probability is going to be virtually indistinguishable from “not possible”. Your statement about “more likely than something impossible” would be a quibble equivalent to saying that 1/google is vastly more likely than something impossible – it’s of academic interest only, as the numbers aren’t going to have anything to do with the physical universe. If you say that it’s identical down to having the same people, I’d say you’ve entered the realm of fantasy. ---
**Author:** ![begbert2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/begbert2/32/3357_2.png) [@begbert2](https://boards.straightdope.com/u/begbert2)\ **Post date:** [October 30, 2006, 11:20pm UTC](https://boards.straightdope.com/t/so-there-exists-another-world-with-someone-like-me-in-it/378404/24 "2006-10-30T23:20:27Z")
[QUOTE=CalMeacham] It depends on what you mean by “identical to earth”. If you mean about the same size and composition then it’s trivial. Even if you mean similar makeup down to water and even having life, I’ll give you good odds. If you mean that it looks like a virtual clone of Earth, down to the same continents, the probability is going to be virtually indistinguishable from “not possible”. Your statement about “more likely than something impossible” would be a quibble equivalent to saying that 1/google is vastly more likely than something impossible – it’s of academic interest only, as the numbers aren’t going to have anything to do with the physical universe. If you say that it’s identical down to having the same people, I’d say you’ve entered the realm of fantasy. [/QUOTE] Given that we rolled into this with the understanding that we’re talking about “an infinite universe”, which presumably is meant to be interpreted as containing “an infinite number of planets”, I don’t think your position is correct; you are being fooled by the fact that “infinite” is not a number. If you are dealing with an “infinite” number of planets, then you are dealing with the spatial equivalent of flipping the coin until it gets heads; unless it’s impossible to do, you are going to do it eventually. If there is a non-zero probability of the earth naturally recurring elsewhere, inhabitants and all, then over an infinite number of planets, it’s probably happened. In fact, it’s probably happened an infinite number of times, with an infinite number of every minor and major variation. In other words: any infintessimal probability \* an infinite number of “chances” approaches certainty; any impossibility remains impossible. So it’s not a distinction without a difference. That said, even with an infinite universe with an infinite number of random planets, it is not _certain_ that there are any other planets that resemble us at all. ---
**Author:** ![TimeWinder](https://avatars.discourse-cdn.com/v4/letter/t/bcef8e/32.png) [@TimeWinder](https://boards.straightdope.com/u/TimeWinder)\ **Post date:** [October 30, 2006, 11:42pm UTC](https://boards.straightdope.com/t/so-there-exists-another-world-with-someone-like-me-in-it/378404/25 "2006-10-30T23:42:24Z")
[QUOTE=Sam Stone] If the universe is truly infinite, then there will be some random combination of atoms elsewhere that exactly mimic the earth. [/QUOTE] No. Consider a universe that contains only two things: one earth, and an infinite number of orange-and-blue striped ping-pong balls. There ya go: an example where the universe is infinite, but the earth is unique. Things can be unique even in an infinite space. And the original premise is false, too-the universe (probably) contains a finite, not infinite, amount of matter. ---
**Author:** ![Astroboy14](https://avatars.discourse-cdn.com/v4/letter/a/df705f/32.png) [@Astroboy14](https://boards.straightdope.com/u/Astroboy14)\ **Post date:** [October 30, 2006, 11:50pm UTC](https://boards.straightdope.com/t/so-there-exists-another-world-with-someone-like-me-in-it/378404/26 "2006-10-30T23:50:54Z")
[QUOTE=glee] If the Universe really is infinite (and there’s no evidence it is), then there would be infinite exact copies of ourselves, typing exactly the same messages on exactly the same SDMB board at exactly the same time. 😕 Infinity is **really** big. [/QUOTE] No wonder the hamsters are so overwhelmed! ---
**Author:** ![begbert2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/begbert2/32/3357_2.png) [@begbert2](https://boards.straightdope.com/u/begbert2)\ **Post date:** [October 31, 2006, 12:01am UTC](https://boards.straightdope.com/t/so-there-exists-another-world-with-someone-like-me-in-it/378404/27 "2006-10-31T00:01:01Z")
[QUOTE=Astroboy14] No wonder the hamsters are so overwhelmed! [/QUOTE] Yeah; does this mean that if I should happen to post anything stupid (heaven forbid) that I can blame it on an alternate-planet doppleganger, who’s networked into our planet’s SDMB from across space? 🆒 ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [October 31, 2006, 1:16am UTC](https://boards.straightdope.com/t/so-there-exists-another-world-with-someone-like-me-in-it/378404/28 "2006-10-31T01:16:54Z")
**Begbert** == nope. read my comments above. [Previous page](https://boards.straightdope.com/t/so-there-exists-another-world-with-someone-like-me-in-it/378404.md?page=1)