It sounds as if your physicist friend was engaging with the Strong Anthropic principle, which I'll try and do some justice to.
The Strong Anthropic principle
First, we should distinguish the “strong” Anthropic Principle from the “weak” one.
The weak one is roughly along the lines of “isn’t it lucky we live just far enough away from the Sun to live”. And similar arguments, like “lucky that humans got a chance to evolve when the Dinosaurs cacked it” etc. It’s weak because this argument can be countered by the “humans are simply self-selecting observers who live on one lucky ball of rock” argument.
The strong version of the Anthropic Principle is the observation that this Universe appears to have been designed to allow life to exist. In any form. At all.
Out of all the infinitely variable boundary conditions of the Universe (the Gravitational constant, the relative strength of the Strong and Weak forces, and many others) the Universe just *happens* to have, or to embody, the exact set of parameters which make matter, space and life itself possible.
Note the emphasis on “possible”. We are not talking about there being a universe which happened to give rise to humans, baboons and bacteria. That would be the weak Anthropic principle.
We are talking about there being a universe where life is possible in any form whatever. If one of the Universe’s constants were to change by a few decimal places then the Universe would consist only of hydrogen, or only of baryons - or it would have lasted only a few millenia before crunching back on itself. The prima-facie odds of getting even carbon-synthesis to work are extraordinarily remote, and everything else has to be “just right” as well
The odds are literally infinitesimal that our Universe just happened to get it right. The religious, supernatural theory that the Universe was designed - and designed for us - is strongly supported by the extraordinary unlikelihood of the Universe being able to support any kind of life.
The usual (materialistic or atheistic) counter-argument against the (strong) Anthropic Principle is the theory that there are quadrillions of parallel Universes, one of which is ours. Ours is only special in that we are in it to observe it’s existence.
This parallel universe theory (apart from being a tired Star-Trek trope) turns out to be a non-disprovable. Any “other” Universe would have to be completely orthogonal to this one, with no interaction of any kind. If a scientist could detect another Universe, he would have - by definition - simply have detected more of ‘the’ Universe. The so-called ‘universes’ of Brane theory, hyperdimensional regions of dark matter interacting weakly with our own - these are part of “the” Universe, which is revealed to be a multiply-connected region.
Strict materialists would therefore have to adopt the position that there exist unthinkable infinities of rigidly unknowable and undetectable Universes covering the gamut of all possible physical constants in order for us to have become self-selected observers of this “one” Universe - the one that happens to have the right conditions for life.
This position “might” be true - but by its very nature it cannot be proven (”Hey! I've detected a Universe which (by definition) is totally orthogonal from this one” is a statement that cannot be true). Materialists have to move to a position not readily distinguishable from religious belief in order to contest the logical consequence of the (strong) Anthropic Principle - which is that this Universe has been extremely precisely tailored to the existence of life.
Hope this is helpful/useful.
“Hope this is helpful/useful. “
It was. As long as helpful/useful means the same as ‘head exploded while reading’.
: )
Not useful!
Well, Godel would allow this statement.
Thanks for the post. I actually discussed this precise issue with the physicist. What annoyed him about the quadrillions of universe argument is that even if universes were being randomly created (that is random in terms of the constants of the General Model) at an unfathomably fast rate, the probability of one having constants that support life still makes our universe surpassingly improbable. We're talking probabilities in the range of, if I recall correctly, 10^-408. Those are silly small numbers--even if you created a new universe once a nanosecond for the entire life of our universe, you would only have shaved the numbers up to, maybe, 10^-400 (some handwaving on the numbers alert--these are WAG's to illustrate a point, not to be precise).
Who knows, the quadrillions of alternate universe thesis may be disprovable someday. But according to this fellow, it still doesn't get you to any reasonable chance that any life-supporting universe would ever occur.
I really cannot say much more his thinking about this subject without making it obvious who he was and this was a private conversation.