Hmm... intelligence can be hard to find these days on Earth. But surely there is intelligent life in space?

Astrobiologist Charley Lineweaver wants us to rethink our place in the universe. In this entertaining talk from the 2013 TEDxCanberra, Charley explores what he sees as the flawed logic of much of what we think about our evolution, and asks the big question: is there anybody (else) out there?

Watch it on YouTube: Science, humility and the fallacy of the planet of the apes

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What do you think? Let us know you thoughts in the comments!

This barefooted astrobiologist is my PhD supervisor and I can pass on your comments to him - he doesn't do social media ... doesn't even have a mobile phone ;-) .

You can also read the paper at or contact Charley directly at

I love Charlie but this seems lacking to me.

The Fermi paradox does NOT necessarily assume that smartness is selected for.

It assumes that smartness is interesting and different and something worth searching for.

Charlie is a clever sophist but I don't find this argument compelling.

Thanks for the comment David. I have passed it on to Charley.

I suspect, Charley would agree with you that human-like intelligence (if that is what we mean by 'smartness') is interesting and different and something worth searching for (see his words from the paper below).

I understand Charley's point is that we should not expect 'big brained' life forms elsewhere in the universe because it does not look like life always evolves towards this phenotype to fill a 'radio-telescope / spacecraft building niche'.

If Charley responds, I shall post his reply here. 


From his paper on this topic:

If human-like intelligence were so useful, we should see many independent examples of it in biology, and we could cite many creatures who had involved on independent continents to inhabit the "intelligence niche". But we can’t. Human-like intelligence seems to be what its name implies - species specific.

I have argued that the fossil record strongly suggests that human-like intelligence is not a convergent feature of evolution. The evidence is indirect and suggestive, but it is, I think, the best we have. Despite this evidence, I am a strong supporter of SETI - because I may be wrong about how the evidence is best interpreted, and because SETI is relatively cheap science. SETI is the exploration of new parameter space with new instruments – a proven recipe for scientific discovery. However, we do not need to misinterpret the fossil record to justify this inspiring research.

If we should not expect 'big brained' E.T. to be common then I guess this leads to the question of what features we should expect to be common to life beyond Earth. Okay, Avatar is only a movie but how reasonable is it for us to expect humanoid Na'vi on planets around Alpha-Cen?

In another paper, (, we suggest that the features which are common to all life forms on Earth are the most likely features of terrestrial life that could be shared by life elsewhere in the universe. For example, features such as: liquid water as the solvent, carbon as the scaffold for biochemistry, the stoichiometry of the major bioelements, the LEGO principle, homochirality, free energy from thermodynamic disequilibria and the Darwinian evolution of inheritable molecules. Other frequently espoused candidate features such as multicellularity and sexual reproduction are less secure because they are based on subjective notions of universal fitness.

Of course, watching the activities of multicellular and sexually reproducing Na'vi makes for entertaining viewing, especially in IMAX 3D ;-)

Liquid water as a solvent was also what I thought was a key property of life, and others with much stronger biochemistry knowledge than I (not hard to do :) ) have said so too, so I was shocked to listen to Loren Williams on "Talk to an Astrobiologist" (on autopilot on SAGANLive) that water was likely not a key property of life. What was your take on this?

Yeah, Loren's comment about liquid water as solvent not being a key requirement for life took me by a little by surprise too, but I am glad that chemists and biochemists like Loren are starting to become more conscious about not simply assuming water is a necessity.

Whether life elsewhere can be based on liquids besides water is an open question. Authors such as Benner, Bains and Baross (B-cubed?) have questioned water as the only solvent and discussed alternative biochemistries.

If a liquid solvent is a necessity so that biomolecules/ions can move freely and interact with enough frequency then one could contemplate life in ammonia, ethane, methane (or mixtures of solvent) (see Wiki's entry on Non-water solvents) . However, in terms of abundance in the universe and more importantly around regions where planetary systems form, I think water is the most abundant molecule with potential to be an abundant liquid solvent.

Whilst some have suggested that water's unique proprieties (e.g. polarity, relatively high heat capacity, hydrogen bonding, floating ice) makes it the "best" solvent for life, we should be very careful with such an argument because as Sagan himself noted, we could be accused of behaving as carbon chauvinists and water chauvinists.

Nevertheless, if we are searching for extraterrestrial life that is like life on Earth (and as we know it), then it is probably safe to assume that liquid water will be a key requirement and therefore the "follow the water" strategy is worthwhile.

I would also like to point out that I got fired from being the book review editor of Astrobiology Journal because I was trying to publish Charley's essay on this very topic.  Editor didn't like it and I insisted that, even though I didn't agree with the conclusion, it was well-written and interesting and should be published.  I insisted so emphatically that I was removed from being book-review editor!!!

That's crazy! Fired for wanting an alternative taste? The McDonaldization of science has begun...

Charley writes:


Hi David,

The last time we met was, I think, at an astrobiology meeting in Houston. You were wearing all black and you told me that Richard Branson sure knew how to throw a party.

I'm very glad that you stuck up for my book review  of "Scientists Debate Gaia" ( even though you didn't agree with it. You're a man of Jeffersonian principles and I appreciate your allowing my "clever sophistry" to appear in "Dr G's Astrobiology Bookshelf".

Maybe we could have a constructive discussion about what parts of it you disagreed with.
I'll defend your right to disagree with me.
I'm sorry that you lost your book review editor job. You were a good editor.

In your comments about my TEDxCanberra talk you write "The Fermi paradox does NOT necessarily assume that smartness is selected for. It assumes that smartness is interesting and different and something worth searching for."

I disagree. I think the Fermi paradox does necessarily assume that "smartness" is selected for.

As Wikipedia and I understand it:

"The Fermi paradox (or Fermi's paradox) is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilization and humanity's lack of contact with, or evidence for, such civilizations."

It seems to me that the paradox depends on making "high estimates of the probability of the existence of extraterrestrial civilization". This seems reasonable. If you don't see any reasons for civilizations to be out there, then you don't have much of a paradox. If Fermi thought that the probability of the existence of extraterrestrial civilizations was very low, he wouldn't have asked "Where is everybody?"

So maybe our disagreement comes down to the question: Does the existence of extraterrestrial civilizations depend on "smartness" being selected for. I think it does since I can't think of another way in which ET civilizations could come about.

I suspect that Grinspoon's version of the Fermi paradox would not necessarily depend on a high estimate of the probability of ET civilization. It would go something like this:

"Contacting an ET civilization would be incredibly interesting and different and well worth searching for. And even if the probability of ET civilization is very low, we should still ask, and keep asking  "Where is everybody?" Not because we believe they are common, but because the search is so worthwhile."

This is slightly different from the Fermi paradox that Wiki and I are used to. So let us call this Grinspoon's version of the Fermi paradox. But even in this version where the probability of ET civilization can be low, ET civilization still had to evolve and this (I think) would involve being selected for "smartness".
So, I'm at a loss to understand your reasoning.

On another issue, if you are interested in whether (or why) complexity increases with time have a look at our new book:


yours for a better understanding life in the universe,
and best regards to your beautiful cats,

Who else wants to see Charley Lineweaver  as the next Talk to an Astrobiologist speaker?? :)

Well, we could do that if we found a time which worked out (for example late afternoon /evening LA time). Let me know if you have a date / topic in mind and I ask Charley or feel free to email him directly at

Cheers, Adi.



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