John Barrow's book is probably rather hard to read but if it is a good book it will explain that our flesh is mostly made by stuff blown out into space by supernovas so the mass
that I just wrote is very important to us.
Most of the mass in your body is oxygen, carbon, and nitrogen
(there are a lot of hydrogen atoms too but they are little and dont account for much of your mass)
and the only reason that there was O, C, and N floating around in space able to condense onto planets as they formed is that there were supernovas here earlier
O, C, N are only formed in the cores of stars---at Bang time only light stuff like hydrogen and helium were made---but ordinary stars TRAP the O, C, and N that they form.
the only way there can be chemistry complex enough for life is if some stars explode and give us the O, C, N we need for interesting chemistry---supernovas give all the other elements heavier than that too but I'm focussing on my arm, your arm, what is the flesh made of--it came from one or more supernovas
but so did the stuff this computer is made of also---and so on.
So this number N which is 13 billion billion or 13 quintillion is
really important---for supernovas, for life, for sound, for wind, for no end of things.
so John Barrow ought to talk about it. it is one of the built in numbers intrinsic to the universe that apparently got set at the word go. and we depend on it (and several other basic proportions) being right.
he probably also talks about the number 1/137
my only quarrel is he and his friends seem to me to make the whole business a lot more complicated than it needs to be.