Let’s end the review of Sabine Hossenfelder’s book. We did some already: Emergence, Entropy, and Many Worlds. With this post, we’ll have covered the most interesting topics.
Old Hoss, and many like her, find it pleasing to think the universe is purposeless, that everything means nothing, that humans have no preferred role, and so their existence is ultimately empty.
What strange beliefs! Do the attitudes underlying them lead their holders to other errors in thought? Should we trust anything they say? Is this a permanent condition?
Funny how people who make “anthropic” arguments like these below never realize they can be turned around:
We quite literally don’t matter: most of the matter in the universe—about 85 percent—is dark matter, not the stuff we are made of, and in any case, whatever we achieve, it’ll be wiped out by entropy increase eventually.
Some find comfort in this insignificance; others find it disturbing. They’d rather humans play a preferred role. Certainly our own existence must mean something, they insist.
Now I am a tall strapping man, and Old Hoss is a diminutive woman. So, in just the same we are nothing next to the larger mass of dark matter, Old Hoss is nothing next to me: I am more important. The realization that size matters may account for why everybody is getting so fat: they want to matter more—by accumulating matter.
That’s the bad. Now the good. Let’s see where Old Hoss gets it right.
It turns out that in the current models, or theories, favored by physicists there are a handful of “constants”, numbers which cannot be derived but which have to be measured. One of these is called the fine structure constant, which says something about electron charge and the electromagnetic field.
Physicists would like to be able to derive these theory-dependent measures from first principles, but they can’t. And maybe some of them aren’t theory-dependent, and are really part of The Way Things Are.
If that’s so, then there has to be a reason the measures take the values they do. There has to be a cause of them. What is it?
The most interesting answer being forbidden as “ascientific” (Old Hoss’s word), physicists seek for others. One answer is to suppose a multiverse of universes were created, one for each possible value and combination of the “constants”—which aren’t then constant, but let that pass.
How many combinations is this? Well, if you allow any value in the continuum, there is an uncountable infinity of universes, a number unimaginably larger than a countable infinity of them. This situation immediately falls under the same Overseer objection we gave for Many Worlds, because there has to be a cause to separate and control and create all the possibilities. And this is so even if the distribution of universes is “random”—which only means unknown.
Some physicists—not Old Hoss—think they can get around this fatality by positing a “probability distribution” over “not-so-constants'” values.
If [physicists] then try to calculate the probability for some observation [of “constants’s” value] in our universe, that merely rephrases whatever they postulated, so one doesn’t learn anything from it—garbage in, garbage out. But it creates a new problem, namely that now they have to explain what the probability is that someone observes something in the multiverse in the first place.
This is right. Can simulations find the right answer? Only if the programmers know them in advance. Simulations are models, and all models only say what they are told to say.
We already knew, of course, that not all values of the cosmological constant are compatible with out observations, because this constant determines how fast the universe expands, and if it expands too fast, galaxies are ripped apart. It is certainly nice to see how this happens in a computer simulation, but elaborations about dolphins in the multiverse don’t bring further insights; they just add an arbitrary, unobservable probability distribution over unobservable universes.
Amen.
She tarnishes this triumph later by demonstrating an incomplete knowledge of probability. Her ideas seems to match those of David Deutsch, whom we’ll meet later. Both don’t hold truck with subjective Bayes, which is good because in it arguments often become circular, but both think probability can only apply to observed frequencies, which is false. There is a Third Way, which is logical probability, also called objective probability (or objective Bayes, though that has ambiguities). We’ll return to this another day.
Old Hoss skirts around the Dog The Didn’t Bark, only hinting distantly at the problem. Why is there something rather than nothing? Why indeed! She teases Lawrence Krauss, who wrote A Universe from Nothing, and then proceeded to call quantum fluctuations “nothing”.
But she never tackles The Question herself, thinking it ascientific. What’s amusing is that many have given the question considerable thought, and their answers conclude the opposite of the Great Bluff that all things are merely particles bumping into each other, that we are insignificant, and that the universe is purposeless.
Wonder why she didn’t explore those.
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