[kerkeslager]

Bullshit like this is exactly why I think scientists are better philosophers than philosophers are. The text you've quoted, is, frankly, not the writings of an intelligent person.

The reason I'm being very blunt about this, is because bullshit like this is actively harmful. Science is fucking important. Science is what resulted in the technology you're using to read this. Science is, with non-negligible probability, the basis of medicine that prevented you from dying before the age of 5 to be able to read this. When philosophers posit that they can inspect the their own navels and find deep truths about the world, they are undermining one of the fundamental pillars of society that holds up so much of the positive changes humans have been able to make.

We need to call this what it is--nonsense and misinformation--and stop amplifying its signal.

> By ‘Bayesian’ philosophy of science I mean the position that (1) the objective of science is, or should be, to increase our ‘credence’ for true theories, and that (2) the credences held by a rational thinker obey the probability calculus. However, if T is an explanatory theory (e.g. ‘the sun is powered by nuclear fusion’), then its negation ~T (‘the sun is not powered by nuclear fusion’) is not an explanation at all. Therefore, suppose (implausibly, for the sake of argument) that one could quantify ‘the property that science strives to maximise’. If T had an amount q of that, then ~T would have none at all, not 1-q as the probability calculus would require if q were a probability.

Of course "the sun is not powered by nuclear fusion" IS an explanation, it's just not an explanation of a phenomenon we observe, which is why most scientists don't believe "the sun is not powered by nuclear fusion". If we observed something about the sun that was not consistent with the hypothesis that it is powered by nuclear fusion, "the sun is not powered by nuclear fusion" would indeed be an explanation of what we were observing.

This is all sidestepping the absurdity that Deutsch doesn't seem to understand that "none at all" has a mathematical representation, 0, meaning that if p = 1 - q = 0, then q = 1. This is not difficult math here, folks.

> Also, the conjunction (T₁ & T₂) of two mutually inconsistent explanatory theories T₁ and T₂ (such as quantum theory and relativity) is provably false, and therefore has zero probability. Yet it embodies some understanding of the world and is definitely better than nothing.

Uh sure, which is why nobody with a brain takes the conjunction of those two things. This isn't a criticism of Bayesian philosophy of science, it's a straw man argument.

> Furthermore if we expect, with Popper, that all our best theories of fundamental physics are going to be superseded eventually, and we therefore believe their negations, it is still those false theories, not their true negations, that constitute all our deepest knowledge of physics.

Deutsch apparently doesn't know what an approximation is, and instead thinks of correct/incorrect as a binary. Relevant https://hermiene.net/essays-trans/relativity_of_wrong.html

[n4r9]

Deutsch is primarily a physicist, not a philosopher. I'm not a fan of his philosophical takes either but he is not as stupid as you infer. He invented the Deutsch-Josza algorithm along with Richard Josza, the first example of absolute quantum speedup.

[kerkeslager]

Doctor Oz was at one time a doctor, too, but he's also been a blight on society, spreading medical misinformation for decades.

A lot can go wrong with a person's brain between the publication of Deutsch-Josza (1985, 1992) and the writing of the linked post (2014).

I'd also note that the algorithm described is more a work of math than an example of experimental science. It's not creating a hypothesis and testing it, it's writing an algorithm for a (then-theorized) computer system. So I wouldn't say that this lends credence to his ideas on the validity of hypotheses.

[n4r9]

Perhaps, but I don't think that's what happened. He continued publishing good quality research in quantum theory and quantum computation until I was doing my PhD, which is just before 2014, and likely still does.

As I say, I also disagree with his philosophical (and political) viewpoints. But your dismissal above is based on a pretty shallow reading alongside unfounded personal attacks.

[kerkeslager]

Did you read past the first few paragraphs? I think I explained why I disagree with Deutsch pretty thoroughly.

[BlandDuck]

I agree entirely. As a professional scientist who routinely uses Bayesian methods to solve complex computational and statistical problems, with actual real world applications, I cannot stress enough how irrelevant such philosophical musings about the foundations of Bayesian Statistics are for getting actual science work done.

[parodysbird]

Because the use of Bayesian models does not require Bayesian epistemology, which, unfortunately, a lot of people conflate.

Here is a decent paper by a statistician about this issue: https://arxiv.org/abs/1006.3868

[kerkeslager]

That's missing the point--philosophy as a whole is not required for science. Invertebrates were adjusting their beliefs to observations (science) long before the first philosopher. I'm not confusing Bayesian models with Bayesian epistemology.

What this is at its essence is that science has allowed us to evolve, learn to kill lions and bears, create agriculture, build ships, cure diseases, travel to the moon, build AI, etc. And all this time while science has been empowering humans and saving lives, science has been under attack by philosophy. You have a scientist saying, "I observe that solar and lunar patterns are more consistent with the earth revolving around the sun" and a philosopher saying "ackchyually the bible says the sun revolves around the earth". When evidence (collected through scientific methods) for a hypothesis becomes overwhelming, the last refuge of ignorance is the philosopher saying, "ackchyually, you don't know that because nothing is truly knowable".

Epistemology is an attempt to understand how we know things, and Bayesian epistemology is probably the best description of how we know things based on science. It's a description, based on observation of how scientists practice science, of how science works.

So when philosophers come in and say Bayesian epistemology doesn't work, they're saying science doesn't work. It's yet another attack on science by philosophers.

And as I said in my other post, Popper's criticism of Bayesian epistemology is actually smart: he does understand what he's talking about, it just doesn't, ultimately, matter much, because the practice of science de facto works, in practice, even if the philosophical model says it doesn't. If all the nuance of Bayesian epistemology and Popper's ideas isn't captured, it's easy for it just to become a straw man argument for philosophers to say that science doesn't work. When it comes down to it, the way people talk about Popper and Bayesian epistemology is just a more sophisticated version of "ackchyually, you don't know that because nothing is truly knowable".

I'm not defending Bayesian epistemology, per se. I'm defending science, as it's practiced, because as I said, science is fucking important. Now, more than ever, in the era of anti-vaxxers and climate change denial, we desperately need people to believe in science.

[parodysbird]

> Invertebrates were adjusting their beliefs to observations (science) long before the first philosopher.

To underscore the bad science you are led to in terms of assumed truth, let alone hypothesis: there is very little evidence or justification or explanation that any of the processes used by the invertebrate here execute calculation that obeys the very specific axioms of probability and updates to a state in accordance with Bayes' theorem. Stimulus response is not Bayes' theorem. Updating a state from new inputs is not Bayes' theorem.

[kerkeslager]

Learning from observation is the basis of science, and invertebrates certainly do that.

A lot has changed since invertebrates started doing that. Not only have we evolved more senses than the first invertebrates, we've also developed methods such as Bayesian inference to combine the results of multiple observations, as well as numerous methods for removing confounding variables such as control groups and regression analysis. Unsurprisingly this has led us to discover a lot more with science, with a lot more accuracy, than invertebrates.

And yes, updating a state from new inputs is not literally Bayes theorem, which is why nobody said it was. However, the process of updating a belief confidence from new inputs as it is done today can be modeled today using Bayesian inference. No, invertebrates don't do that--which is again, why I never said they did.

It's a bit tiresome to be corrected by people who clearly don't seem to understand that Bayes theorem, Bayesian inference, and Bayesian epistemology are all named after the same guy because they're all built on each other in that order. Yes, they aren't all the same thing, but if you're jumping in with that as if it's a correction, you certainly don't understand the concepts.

[n4r9]

Could you give an example of where a philosopher has impeded science in the way you describe? Where it has been not just irrelevant, but obstructive? Irrelevant is fine - science and the philosophy of science have different goals. You might as well say that chemistry is irrelevant to mathematics.

[parodysbird]

> Bayesian epistemology is probably the best description of how we know things based on science.

This is wrong, and it's a bit ironic you are so adamant on a point that is bad philosophy and leads to bad science as a way of insisting that philosophy has no relevance for science.

[kerkeslager]

Okay, what's your explanation for how we can trust science?

[namaria]

You're grossly misrepresenting both science and philosophy. Science is a conscious and self referential effort, it has nothing to do with animals learning how to survive in their environment. Philosophy is definitely not bible thumping.

[kerkeslager]

> Science is a conscious and self referential effort

Is this supposed to be a meaningful sequence of words?

> it has nothing to do with animals learning how to survive in their environment.

As an animal who would have died in childbirth and taken my mom with me were it not for science, I disagree.

[parodysbird]

I don't think you know what you're responding to, but in any case, regarding Deutsch, he "laid the foundations of the quantum theory of computation, and subsequently made or participated in many of the most important advances in the field, including the discovery of the first quantum algorithms, the theory of quantum logic gates and quantum computational networks, the first quantum error-correction scheme, and several fundamental quantum universality results."

[PunchTornado]

you should really try to think and understand what the other is saying, because your text doesn't show that you've put the effort.

[cubefox]

> Bullshit like this is exactly why I think scientists are better philosophers than philosophers are. The text you've quoted, is, frankly, not the writings of an intelligent person.

Which instantly refutes your position, because the alleged "bullshit" he quoted was written by a scientist, David Deutsch, not a by philosopher. Meanwhile, the defenders of "Bayesian philosophy of science" and (largely synonymous) "Bayesian epistemology" are mainly philosophers.

Am I correct in assuming you will now account for the above mistake and change your opinion to "Bullshit like this is exactly why I think philosophers are better philosophers than scientists are"?

[kerkeslager]

If you look up what Deutsch actually did, I think you'll find that he worked on quantum algorithms, making him more of a mathematician than a scientist since he never actually did any experimental work that I can see. But it's sort of irrelevant unless you're trying to make an appeal to Deutsch's authority as a scientist. You wouldn't commit such a logical fallacy, would you?

If you insist on calling Deutsch a scientist, fine, go ahead. That doesn't change my argument in any way, but you'll have to actually read the post you're responding to to know that.

> Am I correct in assuming you will now account for the above mistake and change your opinion to "Bullshit like this is exactly why I think philosophers are better philosophers than scientists are"?

Probably the better thing to do would be to simply remove that paragraph since people like you don't read past the first thing you can find to disagree with. The rest of the post stands on its own fine, but I can't edit it now.