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Post Voting Period
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after 2 votes the winner is...
Voting Style: Open Point System: 7 Point
Started: 10/23/2014 Category: Science
Updated: 3 years ago Status: Post Voting Period
Viewed: 836 times Debate No: 63830
Debate Rounds (3)
Comments (3)
Votes (2)




I've gotta revisit this one and get some other perspectives.

Looking for someone who believes in other life forms (or at least a high probability of them) in our universe, originating from planets other than earth, and being able to make contact with our planet.

Please give me at least some shred of a reason to even consider it a mathematical possibility. A physical possibility.


I assume this round is for acceptance, so therefore I accept this debate. I will attempt to show how their is a high probability of extraterrestrial life using both mathmatical and scientific logic.
Debate Round No. 1


From a mathematics standpoint it would be impossible to discern any pattern that would favor the probability of other life anywhere outside of earth without at least 1 other known instance to correlate to. It takes 2 points to make the beginnings of any trend, and as it stands there is only one. We seem to favor the idea that there could be life like ours by looking for like circumstances to our own planet, but that idea is a futile one when it comes down to the numbers.

Out of the vanishingly small area we are able to sample (that being our immediate surrounding galaxy's and only those that happen to have been emitting light long enough to be intercepted by our planet in the also vanishingly small time frame we've been able to even record such signals) we have only noted a small percentage of planets with similar conditions to our own.

An astronomy article from The Guardian (all links posted below) states there to currently be 2 Billion of them in the Milky Way. Out of a total planet count estimate coming in at at least 100 billion planets. Note also that this is stated as a minimum ... every billion thy are off by only decreases this earth like planet ratio. For this argument ill low ball it by several billion and just call it at 100 billion. We are down to a 1 in 50 billion chance now ... that a planet even has earthlike properties in this solar system. On top of that if you take into account how many earthlike planets that we are close enough to to know that they do not have life on them (and for the sake of the arguement we want to count ourselves which still seems flawed to me) that number is far far lower.

On top of that, consider the fact that we have several instances even in our known time frame of life forms becoming extinct. To not count the fact that, of that <1 in 50 billion chance, an alien species might only exist for mere seconds and its planet never again render another life form seems very likely to me. The chance that they would ever achieve space flight is a daunting number. The chance that they would have the same drive to want to explore space at all could be equally as impossible. In the numbers game of being able to travel light years from our original planet, that numerator is still a 0 ... you can't even count us as an example for that probability to occur.

I guess my base point in all this is that you can only make extremely (and i cant over stress how extremely) small probabilities if you only have one numerator and your capability to explore grows exponentially and has rendered nothing. Second that you cant make any sound prediction for a second, third, or fourth occurrence on record to relate them.

To say we can expect to discover another life form or them to discover us is as unfounded as seeing but one wave and labeling it a tidal change that is sure to come around again and again. You only have one instance of it. And at that you have no idea what even created that instance in the first place. The wave from my example could have been started by anything. Whats to say given 1 data point that there will assuredly be another occurrence? If you had some better understanding of the phenomena you're observing that would allow you to associate some cycle to your instance (in the way you would find a tangent to something moving in an arc) you're golden. But with 1 instance we simply do not have that.

If you wanted to compare maybe that our universe expands then collapses and re expands again to a point where an instance like us exists again ... by our numbers that would be an absolute certainty. But for 2 to exist at the same time is impossible to prove and can only be conceived through an overwhelmingly small chance through emperical probability that would have to use ourselves as a sample to even work. No open survey of people I know of that is in any way asking to be legitimate ever uses themselves as part of the sample.



For my opening argument I would like to focus on the mathematical side of the debate, and will attempt to prove that mathematics support the idea that aliens could potentially exist in the universe.

First I will cite the equation drawn up by American astronomer and astrophysicist Frank Drake [1]. Drake created this formula to attempt to show the likeliness of the human race to find and communicate with an alien race. Note that this formula only applies to the "known universe", or the universe that can be seen by our current technology [2].

In this equation the following variables equal:
  • N is the number of civilizations in our galaxy with which we might hope to be able to communicate
  • R* is the average rate of star formation in our galaxy
  • fp is the fraction of those stars that have planets
  • ne is the average number of planets that can potentially support life per star that has planets
  • fl is the fraction of the above that actually go on to develop life at some point
  • fi is the fraction of the above that actually go on to develop intelligent life
  • fc is the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
  • L is the length of time such civilizations release detectable signals into space
While this formula is highly flexible, because their are so many different variables that can be entered, the results always show that N=1 or higher. This means that in the known universe their is bound to be at least one extraterrestrial species that we could make contact with.

The next formula that I will cite was devised by Sara Seager, a professor at MIT. The new formula is far more rigid than the Drake equation as their are less variables and less room for interpretation in each of the variables.

In this equation the following variables equal:
  • N is the number of planets with detectable biosignature gases
  • N* is the number of stars within the sample
  • FQ is the fraction of quiet stars
  • FHZ is the fraction with rocky planets in the habitable zone
  • FO is the fraction of observable systems
  • FL is the fraction with life
  • FS is the fraction with detectable spectroscopic signatures
The important thing to note here is that N in the Seager equation is quite different from the N in the Drake equation. This N is showing the number of planets whose atmospheres are equivalent to our atmosphere and therefore are likely to harbor life.

In Seager's equation she plugged in the number of stars in the sample (N*) as 30,000, far less than the number of stars in the known universe. When doing this she came to the conclusion that N=2, or that for every 30,000 stars their are at least 2 planets which have a similar atmosphere to our planet. This is incredibly encouraging to those who believe in extraterrestrial life because if instead of entering 30,000 as N* but enter the actual estimate for the number of stars in the universe, their would be a huge number of planets that could harbor life, therefore implying that at least one of them does harbor life.

Back over to you, Con.


Debate Round No. 2


A couple things:

"Applies to the known universe". Since you want to still consider us as the 1 instance that allows your equations to come up as at least 1 then by those calculations we could make the conclusion that we've already met that alien species and it is us.

A 1 as an answer would also indicate that there is no other possible life out there to meet. Everything else those equations use as a factor is a fraction (and very very tiny ones at that) that make any number these equations calculate an infinitesimally small amount larger than 1.

Additionally (as I mentioned in the previous argument), if you were not to count us you would always come up with a zero.

Or we could look at the trend your professors have shown in how their equations have grown and see that the next variable in them (the one not included) as a technology we don't yet posess to discover these lifeforms.

Say for instance your "length of time such civilizations release detectable signals into space" is not ever long enough or the method is never fast enough to reach those lifeforms. That's the extent of your known universe. Ill throw a hypothetical in here by saying, what if we discover that travelling faster than light is the only way to conceivably reach one of those lifeforms by expanding our range. We don't have that ... that'd be a 0 factor that would debase the whole equation. If you said that was the absolute equation for finding life before 1820 it would have been a 0 by the above standards as well.

My point being that for whatever hope we might have of finding any of those lifeforms, for every moment that we don't we are just decreasing the possibility more. We can build ever increasing variables onto the ends of those equations to meet our own knowledge base, but that is no indication on what the extent of technology is that it would take for us to get far enough in our communication for our spheres of influence to cross with other life. Using our technology as a standard is flawed and is a way to work the numbers for favorable outputs.

Personally I still don't find those outputs favorable. I would certainly never bet on them. I actually like that they used the words "... might hope to be able to communicate with" since that best describes what these equations are geared towards ... hope. There is no reason to think either of these equations will render an exact chance at meeting anything as they all are based off of our current extent which has only rendered us.



My opponent claims that we cannot use mathematics to support the possibility of extra-terrestrial life because we do not have another planet with life which we can compare to our own. I will admit that it is impossible to prove the existence of life throughout the universe without another planet as a guideline, however it is not improbable to say that we can show that it is likely. My two formulas from round two support this claim, as they each show that it is highly likely that their is life outside of earth.

Based on our understanding of how life forms, we can simply claim that if a planet has water and the appropriate conditions (i.e. temperature, radiation, atmosphere, etc.) it is possible that it can harbor life. Based on the sheer size of the universe, their could be thousands of such planets. Therefore it is not improbable to assume that at least one planet in the entire universe other than Earth could be harboring life.

Personally, I believe that the premise for this debate is a little bit too ambitious. Proving that their is life that has the technology to communicate with us is impossible. Supporting the idea that extraterrestrial life exists in any form is much easier, and I have supported it in the second round. Therefore based on the size and age of the universe, it is reasonable to believe that at least one one of these primitive species has evolved to the point where it is technologically advanced enough to get into outer space. However, since it is possible that this species is found millions of light years away from us, it is illogical to presume that they could ever communicate with us. Yet the possibility of their existence is high, which is what truly matters.

I apologize for the short response, I am running out of time to post an argument and I am kind of busy at the moment. Anyways, thanks for the enlightening debate!
Debate Round No. 3
3 comments have been posted on this debate. Showing 1 through 3 records.
Posted by FreedomBeforeEquality 3 years ago
If we hav learned anything from this debate (even from middle ground) it should be that you meant to say it's improbable but not impossible. It is most assuredly improbable by all the calculations you've shown. I invite you to dump some numbers in and try one out. The odds are way way against it, it's improbable.
Posted by Atheist-Independent 3 years ago
Hooray, no forfeit! Sorry for the misguided worrying.
Posted by Atheist-Independent 3 years ago
I guess my opponent is going to forfeit. Oh well.
2 votes have been placed for this debate. Showing 1 through 2 records.
Vote Placed by carriead20 3 years ago
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Total points awarded:03 
Reasons for voting decision: Made better arguments, Con can't discredit one specific one.
Vote Placed by 9spaceking 3 years ago
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Total points awarded:03 
Reasons for voting decision: pro has a good suggestion that con cannot deny the least possible existence of aliens