Theories Don’t Have Probabilities: Or, Is The Multiverse Real?

Just one of several copies.
Just one of several copies.

There was in Munich last week a three-day workshop on the soul of science. According to Quanta Magazine, the conference was driven by George Ellis and Joe Silk who wrote a cri de coeur in Nature about defending the integrity of physics.

The crisis, as Ellis and Silk tell it, is the wildly speculative nature of modern physics theories, which they say reflects a dangerous departure from the scientific method. Many of today’s theorists — chief among them the proponents of string theory and the multiverse hypothesis — appear convinced of their ideas on the grounds that they are beautiful or logically compelling, despite the impossibility of testing them. Ellis and Silk accused these theorists of “moving the goalposts” of science and blurring the line between physics and pseudoscience. “The imprimatur of science should be awarded only to a theory that is testable,” Ellis and Silk wrote, thereby disqualifying most of the leading theories of the past 40 years. “Only then can we defend science from attack.”

Now there is much to discuss about this conference and about Ellis and Silk’s paper. But for today, let’s focus on one small item. There is this Joe Polchinski who is a “staunch” string theorist, who had a paper read for him in Munich. According to the magazine:

Polchinski concludes that, considering how far away we are from the exceptionally fine grain of nature’s fundamental distance scale, we should count ourselves lucky: “String theory exists, and we have found it.” (Polchinski also used Dawid’s non-empirical arguments to calculate the Bayesian odds that the multiverse exists as 94 percent — a value that has been ridiculed by the Internet’s vocal multiverse critics.)

The critic is Peter “Not Even Wrong” Woit. Woit quotes Polchinski on the this 94%-calculation:

To conclude this section, I will make a quasi-Bayesian estimate of the likelihood that there is a multiverse. To establish a prior, I note that a multiverse is easy to make: it requires quantum mechanics and general relativity, and it requires that the building blocks of spacetime can exist in many metastable states. We do not know if this last is true. It is true for the building blocks of ordinary matter, and it seems to be a natural corollary to getting physics from geometry. So I will start with a prior of 50%. I will first update this with the fact that the observed cosmological constant is small. Now, if I consider only known theories, this pushes the odds of a multiverse close to 100%. But I have to allow for the possibility that the correct theory is still undiscovered, so I will be conservative and reduce the no-multiverse probability by a factor of two, to 25%. The second update is that the vacuum energy is nonzero. By the same (conservative) logic, I reduce the no-multiverse probability to 12%. The final update is the fact that our outstanding candidate for a theory of quantum gravity, string theory, most likely predicts a multiverse. But again I will be conservative and take only a factor of two. So this is my estimate for the likelihood that the multiverse exists: 94%.

Whew! Everything so far was merely introductory, both for today’s meat and for discussion later. Without taking any opinion on the existence of the multiverse, let the theory, i.e. the very complex set of premises, which include a vast array or metaphysical, physical, and mathematical propositions, from which we can deduce the multiverse be called T. T is a complex proposition, and we are interested in whether T itself is true. Why? Because we know the multiverse is true if T is: the multiverse is a deduction or theorem of T. Polchinski wants to bring in Bayesian theory to answer whether T is true. That was mistake number one.

Mistake two is this statement, “I will start with a prior of 50%.” This makes no sense. Theories do not have probabilities. And since theories are nothing but (complex) propositions, neither do propositions have probabilities. Indeed, no thing has a probability. Probabilities are measures of knowledge, therefore they have to come equipped with gauges, i.e. conditions. In other words, all probability is conditional.

Many think one natural gauge is the proposition W = “T might be true”, which is logically equivalent to W’ = “T is true or it is false”. Both of these are tautologies, which we know are true conditional on our knowledge of logic and understanding of English grammar. But it makes no sense to say, as Polchinski said, Pr(T | W) = 50%. Tautologies are non-informative. The best we can do, as I pointed out earlier, is to deduce T’s contingency, which gives it a interval probability (0,1). Of course, Polchinski may not have had the tautology in mind, but some other gauge. Call this G, which relates to some complex proposition in Polchinski’s head. Then it might be true that Pr(T|G) = 50%.

But what would this G have to look like? Well, it would have to be directly probative of T itself, which means of the propositions of which T is composed. And if Polchinski really had such a G, it is more plausible these G-propositions would already be in T to give it support. Why withhold from T knowledge relevant to multiverses? It doesn’t make sense. But then G might have nothing probative to say about T except its contingency like W, in which case 0 < Pr(T|G) < 1.

According to the rules of probability, Pr(T false | G) = 1 – Pr(T| G). But what does it mean to say T is false? Just that at least one of propositions within T is false. And if we knew that, then we would never entertain T. We would instead modify T (which really means making a brand new T) to remove or transform these troublesome propositions. If G told us which part of T was wrong we would fix it.

Put all this another way. If all we had in contention for the multiverse was T, then T is all we have. We can’t judge its truth or falsehood because we have nothing to compare it to. T is it. It’s T or bust.

I’m sure (though I didn’t check) Polchinski’s numerical calculations are on the money, but the end result is meaningless. T has to be compared not against some internal gut reaction, because there is no such thing as subjective probability, but against the predictions T makes or against rival theories, which provide the only natural comparators. That is, Polchinski might have some alternative theory M in mind, a rival to T such that, given M, the multiverse is not a theory of M. Now Polchinski’s G makes a little more sense.

There may be, and almost certainly are, overlapping elements of T and M, sub-propositions which they share. Nevertheless, T is not deducible from M, nor vice versa, else they would be the same theory. We’ve already seen that it makes little sense to have in G propositions which duplicate the multiverse-predictability propositions in T, and the same objection applies to M. That means G is something else. The simplest would be the “freshman” G, which is “There are two rival theories, T or M, and only one of which can be true”. Therefore, Pr(T|G) = Pr(M|G) = 1/2, via the statistical syllogism. But that’s as far as we can go without additional evidence, such as observations of the multiverse (which won’t be had) or via observables deducible from T or M. Other G are possible, but it is easy enough to see, since there is no such things as subjective probability, we’re up against the unquantifiable. Gut feeling as a decision takes the place of probability. In other words, it’s better to go out and find proof of T or M.

Naturally, everything said holds for theories of any kind. Clever readers will see in the criticism of Polchinski the standard argument why hypothesis testing, whether by wee p-value or Bayes’s rule, is based on the fallacy of the false dichotomy.

More to come…Incidentally, none of what I wrote has any bearing on whether the multiverse actually exists.

Summary Against Modern Thought: On God’s Happiness

This may be proved in three ways. The first...
This may be proved in three ways. The first…
See the first post in this series for an explanation and guide of our tour of Summa Contra Gentiles. All posts are under the category SAMT.

Previous post.

We start Book Two today. Only three books to go! We have so far learned that God necessarily exists, and from that we deduced some limited properties about God. We now move on to what God does.

Chapter 1 Connection of the foregoing with the sequel (alternate translation)

[1] IT is impossible to know a thing perfectly unless we know its operation: since from the mode and species of its operation we gauge the measure and quality of its power, while the power of a thing shows forth its nature: because a thing has naturally an aptitude for work according as it actually has such and such a nature.

Notes This, and ancillary arguments, should be how science is introduced. Science is the search for essence, for natures, for the proper understanding of powers and capabilities. Raw equations, i.e. the mathematization of science, has it place, but equations do not contain maps of natures and powers. Equations can be determinative but not causative. Thomas is after true understanding of the nature of our subject, and not just in making predictions. The nature here are the works of God, since we pushed about as far as raw philosophy absent direct revelation

[2] Now the operation of a thing is twofold, as the Philosopher teaches (9 Metaph.); one that abides in the very worker and is a perfection of the worker himself, such as to sense, to understand, and to will; and another that passes into an outward thing, and is a perfection of the thing made that results from it, such as to heat, to cut, and to build.

Notes If you’re just joining us, or have forgotten, “the” philosopher is Aristotle.

[3] Now both of the aforesaid operations are competent to God: the former, in that He understands, wills, rejoices, and loves; the latter, in that He brings forth things into being, preserves them, and rules them. Since, however, the former operation is a perfection of the operator, while the latter is a perfection of the thing made, and since the agent is naturally prior to the thing made and is the cause thereof, it follows that the first of the aforesaid operations is the reason of the second, and naturally precedes it, as a cause precedes its effect. This is, in fact, clearly seen in human affairs: for the thought and will of the craftsman is the origin and reason of the work of building.

[4] Accordingly the first of the aforesaid operations, as a simple perfection of the operator, claims for itself the name of operation, or again of action: while the second, as being a perfection of the thing made, takes the name of work, wherefore those things which a craftsman brings into being by an action of this kind are said to be his handiwork.

[5] Of the former operation of God we have already spoken in the foregoing Book, where we treated of the divine knowledge and will. Wherefore in order to complete our treatise of the divine truth, it remains for us to treat of the latter operation, whereby, to wit, things are made and governed by God.

[6] We may gather this order from the words quoted above. For first he speaks of meditation on the first kind of operation, when he says: I meditated on all Thy operations, so that we refer operation to the divine intelligence and will. Then he refers to meditation on God’s works when he says, and I meditated on the works of Thy hands, so that by the works of His hands we understand heaven and earth, and all that is brought into being by God, as the handiwork produced by a craftsman.

Notes Nothing at all disagreeable in any of these entries; neither in Chapter 2. The real meat starts next week.

Chapter 1 Connection of the foregoing with the sequel (alternate translation)

[1] THIS meditation on the divine works is indeed necessary in order to build up man’s faith in God.

[2] First, because through meditating on His works we are able somewhat to admire and consider the divine wisdom. For things made by art are indications of the art itself, since they are made in likeness to the art…

[3] Secondly, this consideration leads us to admire the sublime power of God, and consequently begets in men’s hearts a reverence for God. For we must needs conclude that the power of the maker transcends the things made…

[4] Thirdly, this consideration inflames the souls of men to the love of the divine goodness. For whatever goodness and perfection is generally apportioned among various creatures, is all united together in Him universally, as in the source of all goodness, as we proved in the First Book. Wherefore if the goodness, beauty, and sweetness of creatures are so alluring to the minds of men, the fountainhead of the goodness of God Himself, in comparison with the rivulets of goodness which we find in creatures, will draw the entranced minds of men wholly to itself…

[5] Fourthly, this consideration bestows on man a certain likeness to the divine perfection. For it was shown in the First Book that God, by knowing Himself, beholds all other things in Himself. Since then the Christian faith teaches man chiefly about God, and makes him to know creatures by the light of divine revelation, there results in man a certain likeness to the divine wisdom…

This Week In Doom: The Demands And Ravages Of Equality

Image from this site.
Image from this site.

Progressive beasts

We had fun with the foolish Vox explaining that animals “in the wild” suffer from being eaten, from disease, from neglect, from the lack of personal recognition, and so forth, but what was perhaps not obvious was that the demand that we step in and do something was perfectly consistent with the Theory of Equality. Accept as a premise that all can and must be Equal, then it necessarily follows that wild animals should be put under the same strictures, supervisions, and burdens of human animals.

Given Reality as a premise, we are forced to conclude that animals eating each other, and we eating them and them sometimes eating us, is because of the nature or essence of the world. It is the Way Things Are and cannot be changed. Indeed, it also follows that it is insane to wish to change it via human efforts. We cannot alter our nature, nor can we alter the nature of beasts. If we could alter our nature, then the result, if such a thing were even possible, would not be human, because, of course, it is our natures which define what it means to be human. And the same is true for other animals.

Equality demands animals cease misbehaving, but since that is a large program, instead look for increasing demands for vegetarian diets. Of course, it remains to be proven, under Equality, that plants are people, too. But it is true that any systematic harvesting of plants causes the death of a multitude of animals. Hence Equality should lead to the conclusion that human animals should cease being. And, indeed, we see such calls. The difficulty is that once we are absent, there will be nobody left to police the animals. This paradox ought to start some interesting discussions among true progressives.

Unfair parenting

As we all know, the same-sex attracted were unhappy that they could not marry one another. This was because the nature or essence of marriage—holy matrimony, if you will—is constrained to be between just two people, one male, one female, united in “one flesh” toward the final cause of reproduction (just as not all people have two legs, the natural condition, not all marriages produce offspring, the natural condition). The nature of marriage cannot, of course, be altered, just as human nature cannot. But the government, recognizing the earnest and pained calls for Equality, stepped in and created gmarriage so that, currently two, though it is expected to be more, men, or two (or soon more) women could simulate marriage. Equality also demands, and the government is enforcing the requirement, that everybody pretend gmarriage and marriage are identical. This is no surprise, because Equality is and must be an enemy to Reality.

Very well; so much water under the bridge, etc. Now since gmarriage is to be simulation of marriage, in order to be complete, offspring must needs be produced. This is, because of human nature, impossible. But once again the government has heard the pleas and are cooperating with scientists to eliminate, to the extent possible, parents. The nature or essence of parent is the biological mother or father. So if babies are not to be produced by parents, they must come from other means.

Enter “multiplex parenting”, in the news this week and the scientific Equality-driven name for the mixing of DNA from any number of humans, including just one, to create new life—in principle, anyway. The name is Equality-driven because parents can only be the biological mother and father, regardless of what courtesies we extend to some non-parents. The technical term for this marvel-to-be is in vitro gametogenesis. Now whatever the engineering achievement or detriments—nobody expects this to be a flawless process; there will be much “waste”—it is still the case that a human female must volunteer to carry this creation to term. Unless, of course, it is decided midstream to kill it, which a visit to the now well-funded (thanks, Paul Ryan!) Planned Parenthood will “fix”. Regardless, this female might not be the mother, since none of her DNA is required.

Whatever else this process is—and we are edging ever closer to the prophesied Bokanovsky process, about which there is much more to day another day—it is a triumph of Equality.

Incidentally, the Irenist reminds us of this apropos quotation: “Their real children they fabricate by vile arts in a secret place.

Michael Moore’s a Muslim

Equality demands that all religions are equal. Thus this (possibly Photoshopped) image, presented with comment (why progressives are angrily and defiantly embracing Islam waits for another day).


I’ll vote for that

Twelve-year-olds got to do something unusual last week in Cambridge, Mass. They were allowed to vote on how the city spends its money.

Those who wish to congratulate me on predicting this form of Equality (here and here) may do so.

It’s going to take more than two aspirin

Dr. Church loses final appeal at hospital. Board of Directors upholds physician’s expulsion for telling the truth about high-risk LGBT behavior to colleagues. If you close your eyes, disease can’t find you.

Animals Are Killing Animals And We’re Doing Nothing To Stop It

Sealaphobia being passed on from one generation to the next.
Sealaphobia being passed on from one generation to the next.

Social justice warriors have opened a new front in their continuing war against Reality: animal suffering. They’ve noticed it, they hate it, and they will no longer abide it. (H/T to @Outsideness where I first learned of this.)

It has long been an argument from Yours Truly that animals are viciously ripping each other apart, and that if vegetarians and vegans were seriously serious about their positions, they would take steps to stop the slaughter and enforce a vegetable diet on all beings.

Well, Vox has heard me. Yes, in “Wild animals endure illness, injury, and starvation. We should help” Vox explains, or rather paints, a terrifying picture of an unregulated animal kingdom. Wait. Kingdom? Equality is not attainable in such an archaic, medieval political system. This is the first hint that change we can believe in is needed.

You have no conception of the daily horrors animals face. Vox explains—ladies, now is the time to avert your eyes—“Gulls peck out and eat the eyes of baby seals, leaving the blinded pups to die so they can feast on their remains.” It gets worse: “A shrew will paralyze his prey with venom so he can eat the helpless animal alive, bit by bit, for days.”

I myself have witnessed hawks disemboweling rabbits, big fish swallowing little fish, and crows doing things to bodies of the dead that can’t be printed in a family blog. Once I saw a wolverine, with every evidence of pleasure, mercilessly hunt down a squirrel and separate it from its noggin. Mea cupla, though. I like these other animals have killed, gutted, skinned, and eaten many, many animals, having been bred in the far north where such behavior was not then known to be evil.

Vox explains: “The natural suffering of wild animals is real and breathtaking in its enormity, but incredibly little is being done to reduce it…little thought has gone into the question of how to help wild animals avoid natural agonies.” To the progressive, every evil is a problem which must be solved. He believes this axiomatically, just as he believes that because he believes every evil should be solved, that therefore every evil can be solved.

Hence, “Unfortunately, wild animals lack the power in society to speak out and relieve their own suffering like humans, so it’s harder to recognize the urgency of their needs. But we should act on their behalf.”

Vox explains that one of the best ways to reduce suffering is the very method they recommend for humans: birth control; which is to say, birth prevention. “[W]e might be able to humanely reduce population numbers using contraceptives.” I don’t know, though. Can you imagine brigades of SJWs roaming the woods trying to strap condoms on bears? Experience with human animals shows it might be easier, and would be certainly far more effective, to convince grizzlies that sex is meant for pleasure and not procreation.

Reducing births can’t be the only solution, though, as the picture which heads this article proves. Violence is passed on generation after generation. But SJWs have many tactics, the most popular being Screech Shaming. How do we stop seagulls from gruesomely blinding seals? Twitter campaigns, primarily. We get people to hold placards reading “I stand with the #BlindSeals.” Or we get pictures of ocularly deprived seals with their cute little canes and have the New York Times run op-eds denouncing racist gulls. Make that speciest gulls.

Students traumatized by the sudden comprehension that the early bird gets the worm actually means the appalling death of another creature can release lists of demands to cowardly administrators, demands which might include free tuition for all minority animals, creation of departments of seal studies, official recognition that seals are an oppressed group in need of coddling, etc. You know the drill.

Objections? “Some might argue that we shouldn’t intervene in nature because it could cause harmful ripple effects elsewhere in the ecosystem, like through extinction or overpopulation of some species.” Some might. But, Vox explains, “Unfortunately, wild animals lack the power in society to speak out and relieve their own suffering like humans, so it’s harder to recognize the urgency of their needs. But we should act on their behalf.”

The progressive mind can see no rebuttal to this argument.