Matt Ridley ends his excellent Julian Simon Award Lecture with a criticism:

Having paid homage to Julian Simon’s ideas, let me end by disagreeing
with him on one thing. At least I think I am disagreeing with him, but I
may be wrong. He made the argument, which was extraordinary and
repulsive to me when I first heard it as a young and orthodox
eco-pessimist, that the more people in the world, the more invention…

Now there is a version of this argument that – for some peculiar
reason – is very popular among academics, namely that the more people
there are, the greater the chance that one of them will be a genius, a
scientific or technological Messiah.

Occasionally, Julian Simon sounds like he is in this camp. And if he
were here today, — and by Zeus, I wish he were – I would try to persuade
him that this is not the point, that what counts is not how many people
there are but how well they are communicating.

A strange claim.  Isn’t the correct position clearly that both population and communication matter?  A two-person world linked by Skype wouldn’t be very creative.  Neither would a world of a trillion people in solitary confinement.  Creativity requires minds to generate ideas, and mouths to share them.

Ridley continues: 

I would tell him about
the new evidence from Paleolithic Tasmania, from Mesolithic Europe from
the Neolithic Pacific, and from the internet today, that it’s trade and
exchange that breeds innovation, through the meeting and mating of
ideas. That the lonely inspired genius is a myth, promulgated by Nobel
prizes and the patent system.

The importance of rare geniuses is an interesting question for discussion.  But who ever even hinted that lonely geniuses are the crucial ingredient?

This means that stupid people are just as
important as clever ones…

This is frankly an absurd leap.  Geniuses are overrated?  Maybe.  Stupid people are “just as important” for progress as clever ones?  Come on.  Question for Ridley: Whose the most creative person alive with an IQ under 100?  Under 80?

…that the collective intelligence that gives us
incredible improvements in living standards depends on people’s ideas
meeting and mating, more than on how many people there are.

If “meeting and mating” are so important, doesn’t that suggest that creativity will be more than proportional to population?  If so, isn’t population even more important than it seems?

That’s why a
little country like Athens or Genoa or Holland can suddenly lead the
world.

Can?  Sure.  But is it typical for little countries to lead the world in innovation?  Hardly.