If you don’t know what the Fermi paradox is, then it’s pretty pointless reading any further.

For those that do know what the Fermi paradox is, then for what it’s worth, my belief up until 2 years ago was that the Universe is indeed teaming with life, including intelligent life, but that the distances separating intelligent life-forms is so great that the probability of them ever crossing paths is infinitely small.  This is perhaps a good thing.  When we started leaving our little islands and discovering other lands, our encounters with our new found friends on distant shores were pretty detrimental on the whole for the poor blighters we visited.  So IF there is intelligent life out there, and it is separated from us by uncrossable distances – maybe that’s a good thing anyway.  As I said – this is how my thinking went up until June 2011 when things got suddenly turned upside down.

June 2011 was the Starmus Festival in Tenerife and there were some really great speakers there on SETI, and also life on Earth.  I got an answer I really didn’t like from one guy trying to create artificial life.  By “I didn’t like” I mean that it was about to turn my belief of a Universe teeming with life on its head.  I basically asked if there was any active research going on to see if any of Earth’s life forms were based on things other than DNA.  The short answer was not really as nothing other than DNA-based life has ever been seen.  Now this is more than a bit worrying.  DNA as you know is a pretty complex molecule (that is putting it lightly).  Now if life as we know it requires a molecule of this complexity to be put together, in its entirety for it to do its replicating job, then what are the chances of this one-off highly improbable event occurring.  O.K. so yes, I’m well aware that it DID happen here, but was that a case of a pretty near zero probability in a pretty near infinite Universe?  We have evolved, over millions of years, we know all this from the fossil record.  So where are all the DNA pre-cursors that led to the present life-molecule?  Where are all the half starts and dead-ends you would expect with a “Blind Watchmaker” approach to making a DNA molecule?  There doesn’t seem to be any.  What happens when you look at the oldest existing life forms on the planet?  Is it still DNA with these guys?  Seems to be, seems to be DNA all the way down.

Now I have a problem.  There seem to be no pre-cursors, no dead ends no false-starts – just the finished machine.  What is the probability of a DNA molecule coming together, given that you have both the right environmental conditions and all the right elements to hand?  I would venture to say not big.  Richard Dawkins played with computer generated bimorphs, very simple code to produce bilaterally symmetric “insects”.  When he came to write his book he wanted to include pictures of the initial bimorphs he had created, but he couldn’t reproduce them.  Even though the code was very simple, extremely complex behaviour can result from just a few lines of very simple code (fractals, Stephen Wolfram).  But the DNA code is far from simple to begin with, so what are the chances of stumbling upon this magic molecule “Blind Watchmaker” style?  I would venture to say as near dammit to zero as you can possibly imagine.

My argument may appear at first sight to be rather like the fallacious argument as to the improbability of the evolution of the eye, but it is not.  At least in the case of the eye you had a fully functioning cell to work with in the first place.  The DNA problem is going right back to square one.  The creation of an incredibly complex molecule that is able to precisely replicate with error coding built in.  Sorry guys but this is not just the (relatively) simple evolution of an eye (or a Bombardier beetle) – this is a whole different ballpark.

So I am now in the very depressing state of believing that the answer to Fermi’s paradox is that there are no other intelligent life forms out there in the vast expanse of our Universe.

Sir Arthur C Clarke said that either answer (that there IS, or there IS NOT life “out there”) is equally disturbing.  I beg to differ with Sir Arthur.  If we are indeed the only intelligent life form in the Universe, and we go on as we are, then we are likely to also snuff out this unique oasis of life, in the cosmological blink of an eye.

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2 Responses to “The Fermi paradox – where are they?”
  1. Pete says:

    I’ve often wondered what the smallest self-replicating organism would be (e.g. strand of DNA); presumably for life to start, it would have to come together by chance, and for it to continue, assuming it is DNA-based, would have to exist in a soup of amino acids so it could multiply from its surroundings. I can’t imagine it would be a simple molecule though, & it all seems rather unlikely to me. If we do find life on other planets (e.g. Mars), there must be something we’re missing in the calculation? If not, perhaps we really are alone..
    P

  2. Greg Parker says:

    Hi Pete,
    I am no expert on this stuff, but I think a slightly simpler replicating molecule might be RNA but don’t quote me on that. I think that RNA falls short of DNA for life replicating with the lack of “error checking” so DNA I think is a “better” replicator than RNA (but mistakes – random mutation – of course still occur).
    The enormous problem I have with all this is that it seems that we need these complicated molecules – in their entirety – for life. I see no precursors, and I see no life forms based on anything other than DNA. Even the oldest living things on the planet – stromatolites in Shark Bay Australia are DNA/RNA based.
    With no false starts, or blind alleys to be seen and only the finished working product I think the likelihood of this happening anywhere else is pretty close to zero. O.K. so there could be life out there NOT based on DNA, that’s possible, but then why are there no other non-DNA based life forms here on Earth?
    I really think it quite likely that we are alone here.
    All the best,
    Greg
    P.S. Life (or previous life) on Mars. Quite possible – and if so it’s 100% probability that it will be DNA based IMO.

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