Physics is about discovering what the laws
of nature are.
And we've gone some distance towards that.
We're not done but we've gone some good distance
towards that at the present time.
But once you know what the laws of nature
are, another kind of question unfolds itself
which is why are those the laws and not other
laws.
For example, the laws that we understand -- the
standard model of particle physics describes
all the fundamental particles and their interactions
-- has about 30 numbers which you just have
to put in as the result of measuring them
by experiment.
The masses of the different particles, the
quarks, the electrons, the neutrinos, the
strengths of the fundamental force -- various
numbers like that.
And the model works dramatically well as the
recent experiments the Large Hadron Collider
show.
Why are those numbers what they are in our
universe?
Why is the mass of the electron what it is
and not 12 times larger or half the size?
There are dozens of questions like this.
So I developed cosmological natural selection
to try to give an evolutionary account of
this so that there would be a history back
before the Big Bang in which these numbers
could change and evolve through a series of
events like the Big Bang.
And there could be an explanation akin to
natural selection.
Just like you want to know why do people have
two legs and not three legs or five legs or
four legs or six legs.
There's an evolutionary reason for that.
A certain kind of fitness has been improved
over many, many generations and similarly
there could be a notion of fitness of the
laws of nature through approval of many generations.
And cosmological natural selection was an
example of the theory of that kind.
I realized that the only methodology we had
in science, or the best methodology we had
in science for explaining how choices have
been made in the system to all lead to a lot
of structure because one of the mysteries
is why our universe is so structured as it
is on so many scales from organic molecules
and biomolecules up to vast arrays of clusters
of galaxies.
There's enormous structure on such a wide
range of scales.
And that turns out to be tied to the values
of these constants of the standard model of
particle physics.
And so why is that?
And I realized that the only methodology that
was really successful for explaining how choices
were made in nature such as to lead to an
improbable amount of structure is natural
selection.
So for natural selection we need reproduction.
And there was a hypothesis lying around that
universes reproduce through Black Holes, that
inside Black Holes rather than there being
singularities where time ends, there were
basically the births of new regions of space
and time which could become new universes.
And I took over that hypothesis and took over
the hypothesis that maybe the laws of nature
changed slightly which has been made by Johnny
Wheeler in the 1960s, and just added a little
bit which is that those changes should be
very small so that there can be an accumulation
of fitness.
Which leads to a prediction or an observation
that after many, many generations the population
of the universes should be fine-tuned to maximize
the production of Black Holes.
And that has further implications for things
that we can actually try to measure and disprove
experimentally.
So that's, very briefly, the idea of cosmological
natural selection.
