Wednesday, March 29, 2017

Leprechauns and fairies

Why aren’t multiverse—or large universe—hypotheses that imply that there very likely exist fairies and leprechauns dismissed as mere sceptical hypotheses?

17 comments:

Red said...

They are incredulous but whats "sceptical" about likely existence of fairies and leprechauns?

Scott Hill said...

Maybe because the multiverse hypothesis has explanatory power that more mundane hypotheses do not. Some one might reason that the multiverse hypothesis can explain the fine-tuning data. And in that case its explanatory power allows it to rise above a mere skeptical hypothesis.

Alexander R Pruss said...

Idealism also has a lot of explanatory power.

IanS said...

My understanding (purely from consuming popular science) is that physicists’ multiverse hypotheses arise naturally from the physics required to describe this universe (admittedly with a lot of speculation thrown in). They are not dreamed up just, for example, to explain fine tuning. Philosophers’ multiverses may be different…

Unknown said...

Assuming you DO gain explanatory power (rather than just posit an equally-problematic request for explanation), you do so with not only fairies and leprechauns, but with Three Amigos having been a documentary.

SMatthewStolte said...

The reason such theories are not dismissed as mere skeptical hypotheses is that they are false. For if they were true, they would be so dismissed.

IanS said...

Multiverse hypotheses may be untestable, but are they strictly sceptical? To be sceptical in the usual sense, it is not enough that an hypothesis be untestable. It must also propose that things are not as they seem. The hypothesis that leprechauns exist in a universe that we will never be able to visit is untestable. But there no suggestion of delusion or misperception.

Scott Hill said...

I guess I don’t think of Idealism as a *mere* skeptical hypothesis. I’m pretty confident that its false. But I’m not nearly as confident that its false as I am a BIV or evil demon hypothesis. I would say the same thing about the simulation hypothesis. I find that I can’t quite dismiss idealism, the multiverse hypothesis, or the simulation hypothesis in the way that I can easily dismiss the BIV and evil demon hypotheses. I feel that ai have to take them seriously in a way that I don’t have to take mere skeptical hypotheses seriously. Though I do think they might be on the borderline between skeptical and serious hypotheses.


At the very least, I don’t see that the BIV or evil demon hypotheses have any explanatory advantage over more mundane hypotheses. But I do see how multiverse theories might. So, even if Idealism counts as a mere skeptical hypothesis and has lots of explanatory power, the appeal to explanatory power is a way to mark out a difference between the multiverse hypothesis and a common class of skeptical hypotheses even if it can’t mark out the difference between the multiverse hypothesis and *all* types of skeptical hypothesis. Thats at least a bit of progress on the question you raise. Or so it seems to me.

entirelyuseless said...

Common sense says that fairies and leprechauns don't exist in the world around us, and the multiverse theory does not say that they do. Common sense has nothing to say on the question of what you might find if you take a space probe a googolplex miles out. So large universe theories are not skeptical because they are not against common sense, but they simply speak about things that common sense never considers.

In other words, if you want to call large universe theories "skeptical," you should do the same about religious accounts of the world, or the theory of evolution, or quantum mechanics.

Alexander R Pruss said...

These are all really interesting comments.

Ian: *Some* highly speculative physics gives rise to multiverses. But physicists are also attracted to the theories that have multiverses in them because of finetuning considerations. I don't know which line of thought is more dominant.

Ian and entirelyuseless:

If I merely said that there exist yetis according to multiverse theories, then I think your responses would be right. It seems that, and common sense says, there are no yetis *around here*. But fairies and leprechauns aren't merely strange looking kinds of animals: they are *magical* animals. They wave wands around or utter spells, and weird stuff happens, like flowers turning into butterflies. We might say: It seems to us, and common sense says, that weird stuff like that doesn't happen *anywhere*. But on a large enough multiverse theory, there are universes where such things happen. (Quantum mechanics tells us there is a tiny but non-zero chance that each time you wave a wand, a flower turns into a butterfly. Given enough universes, a chance like that will be realized.) In fact, on infinite multiverse theories, there are infinitely many universes where such things happen. (In fact, the same infinite count as the ones where it does not happen.)

(Technical caveat: Maybe nowhere do wand-wavings *cause* flowers to turn into butterflies. But it seems bad enough that somewhere flowers do turn into butterflies each time a fairy waves a wand, and fairies often wave wands (the last clause is needed to rule out the trivial case where there are no wand-wavings).)

Scott:

Brain in vat theories seem to have very similar explanatory power to simulation theories. Both suppose that our complex set of perceptions arise from someone in a "more physically real" universe doing experiments.

Let me be a devil's advocate. :-) An evil demon theory can be an explanatory supplement to idealism: it explains why we have such coherent sensations as of a material world--because a demon wants the evil of error to be widespread. Both evil demon idealism and theistic idealism have an explanatory advantage over a "pure" atheistic idealism. And evil demon idealism has an advantage over Berkeley's theistic idealism, because it better explains why a perfect God allows us to be deceived about the material world--basically, the evil demon idealism can give a free will theodicy for error (the demon freely chooses to deceive us).

Also worth mentioning among sceptical scenarios are Boltzmann brain stories, by the way.

Scott Hill said...

Alex:

I was thinking of solipsistic or near-solipsistic Cartesian versions of the BIV and evil demon cases as the standard skeptical positions. So, in the BIV case, the only things that exist are my brain in a vat and a computer zapping my brain in various ways. And in the evil demon case the only thing that exists is just me and an evil demon causing me to have the sensory experiences that I'm having.

If you go with a version of the BIV case that is matrix like, I agree that it isn't relevantly different than the simulation hypothesis. And I find that I can't dismiss it as mere skepticism. And if you go with a version of Idealism supplemented by an evil or indifferent creator, I can't dismiss that as mere skepticism either.

Although, now that its made explicit, I'm wondering why I think the solipsism matters so much.

For what its worth, I don't share the intuition that we are being deceived about reality if idealism or the simulation hypothesis is true. So in that case I don't think theistic idealism is any worse off in explaining evil relative to demon idealism than regular theism is relative to regular evil demonism.



Alexander R Pruss said...

There is also the variant of the simulation hypothesis that, in order to save computational resources, only your brain is fully simulated. Brains of people in contact with you are simulated less fully -- just enough to produce a pretty good appearance of humanity -- and the billions of people you never come in contact with are only simulated in rough mass outlines. This greatly saves memory and CPU time, so we would expect that if scientists were running computer simulations to study brains, they would do stuff like that, instead of simulating billions of brains.

Scott Hill said...
This comment has been removed by the author.
Scott Hill said...

Yeah that sort of simulation hypothesis and the Boltzmann Brain stories do sound more like skepticism to me. But I still find that I can't dismiss them quite as easily as more Cartesian-like skepticism. Or, at the very least, I think the problem with them seems to require a different diagnoses than more traditional forms of skepticism.

Red said...

Why Theories of Time which seem to deny change, not skeptical hypothesis?

Alexander R Pruss said...

Theories of time that deny change are sceptical theories. Theories of time that merely seem to....

Scott Hill said...

I'd be curious to hear what you think about mereological nihilism. As I recall, you're a nihilist (at least about artifacts). Do you classify such a view as skeptical?