Sorry for the delay! Been busy!

I made the same point myself earlier in the thread but it received no response―which is probably understandable. — Janus

For me the problem with this 'variant' of Kantianism is that it can only explain the form of appearances, not that there are appearances at all. If Kant's 'idealism' asserted that appearances are mere mental contents then, it would be subjective idealism. However, Kant also asserts that there is 'something' about phenomena that it is not 'mental'. However, we are left with no clue on how that 'something' is related to appearances.

I do believe that the great merit of Kant (and epistemic idealism in general) is his view that mind isn't a 'passive' recorder of 'what happens' but that it actively interprets phenomena. I also believe that we can't easily differentiate what is 'mind-dependent' from what is 'mind-independent', an antinomy if you will.

Anti-realists, anti-materialists, anti-physicalists have a vested interest in denying the reality of things in themselves, because to allow them would be to admit that consciousness is not fundamental, and, very often it seems, for religious or spiritual reasons they want to believe that consciousness is fundamental, especially if they don't want to accept the Abrahamic god. One can, without inconsistency, accept the Abrahamic god and be a realist about mind-independent existents. — Janus

Well, I am sympathetic to theism, in fact. IMO, our mind can 'produce' the representation because the 'external reality' is itself intelligible. However, we can only know it by interacting with it and producing a representation of it, which is the 'phenomenal world'. It's not a 'deceptive' veil - at least, if we remember that it is also the result of the interpreteation that our mind makes of the 'external reality'. In fact, I think that the act of 'knowing' is always mediated. The 'external reality' is the 'known', our mind is the 'knower' and the 'phenomenal world' (or the 'representation') is the medium by which our mind can know the external reality. Such a knowledge, however, is imperfect and this is why we make mistakes. To make an analogy, when I read your post, I (the knower) imperfectly know your thoughts (the 'known') via the written texts I read and my own previous knowledge about the English language, what I have studied in philosophy etc (the medium).

Note, however, that I am positing that the 'external reality' itself is intelligible. And as I said elsewhere, I don't think that physicalism alone can explain that intelligibility. Its presence suggests to me that there is at least a 'fundamental mental aspect' of reality, which isn't my mind, our mind, or the 'human mind' in general.

Better to say D’Espagnat developed a more complete epistemic idealist theory grounded in transcendental realism, than to say Kant developed a less complete epistemic theory because it wasn’t. — Mww

Not sure what is your point here. I meant that I prefer d'Espagnat's view than Kant's because I find the latter's view lacking in a way the former's view isn't. So, yeah, d'Espagnat's view perhaps is better described as a (subtle) form of 'transcendental realism'. But despite preferring the view of d'Espagnat I think that Kant's has its merits.

But "interaction-free measurements" work because there is a physical change in the system behavior due to a change in the experimental context, analogous to closing a slit in the double slit experiment. — Apustimelogist

Agreed with that. But this doesn't change the fact that it seems quite different from the classical case. In fact, I believe that your example is perfect here. In de Broglie-Bohm, changing the experimental context has a nonlocal effect also on the measured system. In this, it is quite similar to Copenaghen. Bohm himself acknowledged that Bohr with his 'indivisiblity of the quantum of action' was quite close to his view. Of course, according to Bohm, Bohr's model was incomplete but not 'completely wrong'.

But where is the particle? Since the wave is uniformly spread throughout space, there is no way for us to say that the electron is here or there. When measured, it literally could be found anywhere. So while we know precisely how fast the particle is moving, there is huge uncertainty about its position. And as you see, this conclusion does not depend on our disturbing the particle. We never touched it — Brian Greene, The Fabric of the Cosmos

There are also Interaction-free measurement, which IIRC do not seem to require a direct interaction between the system and the measurement apparatus and yet they do bring an 'update' to the wavefunction.

To make an example: if you emit a particle and a detector detects it, you have a normal measurement, which involves an interaction, and you now know the position of the particle. If you, however, activate the detector and it doesn't detect the particle, you know where the particle is not. This suggests that you was able to 'update' the wavefunction of the particle in question without interacting with it.

If I am not mistaken, in de Broglie-Bohm's view, this involves some kind of nonlocal interaction between the detector and the particle. A QBist would say that no interaction occurred and the 'negative result' update our 'degree of belief' of where the particle is.

In any case, the so called 'interaction-free measurements' are ways to get new information without getting 'positive' results.

So again this lends support to some basic aspects of Kant's (as distinct from Berkeley's) form of idealism. The idea that 'the structure of possible experience constrains what can count as empirical knowledge' has had considerable consequences in many schools of thought beyond quantum mechanics. As for Berkeley, though, these kinds of developments provide a partial vindication - by bringing the observer back to the act of observation ;-) — Wayfarer

Thanks for the Bitbol reminder! In any case, as I said, I believe the great merit of epistemic idealism (of whatever form) is to remind us that the mind has an active role in give an 'order' to what we are experiencing. In other words, we can't neglect the role that the 'constraints of possible experiences' have on what we actually experience.

Still, I honestly think that epistemic idealists (like Bitbol, Kant etc) do go too far.

For instance, in order to avoid to imply that we create the 'empirical world' out of pure thought, Kant had to concede that there is a reality beyond of experience that provide our mind the 'matter', to use Arisostotelian language, for then 'building up' the 'forms' via the faculties of sensibility, intellect and so on. However, it seems to me that if the 'reality beyond/before phenomena' was structureless, it would not possible for us to give it a 'form'.

Personally, I think that D'Espagnat provides a good correction of epistemic idealism. The active role of mind is accepted almost to the degree of Kant etc but, at the same time, D'Espagnat's view accepts that the 'reality beyond/before phenomena' has its own structure that is 'veiled' for us (and by studiying the 'empirical world' we can know 'as through a glass darkly' to borrow again, out of context, St. Paul's famous phrase).

So, yeah, I guess that for me Kant's and Bitbol's approach is incomplete rather than being 'misguided', so to speak.

This is where his nominalism shows through. By designating universals purely mental or linguistic, Berkeley undercuts the possibility of a robust theory of lawlike regularities within his immaterialism. — Wayfarer

Yeah, I agree. That's one of his weak points. But I would also say that his 'immaterialism' by no means implies nominalism. In fact, I would even say that - at least for certain concepts (e.g. mathematics) - Berkeley's own system would actually make more sense with a 'realism about universalism' - as concepts present eternally in the mind of God.

Kant does acknowledge that there is a domain beyond our knowledge - so there is a reality beyond, or in a sense other than how it appears to us. But he avoided the weakness in Berkeley's argument by allowing that the forms of thought (categories) and of intuition are universal structures of cognition, not mere names — though still mind-dependent in his transcendental sense. — Wayfarer

The problem is that in order for our own categories and intuition to 'ordain' the empirical world, I believe you need to posit some structure onto the noumenal and this suggests that we do have some knowledge of the noumenal, i.e. one ends up to a form of 'indirect realism' or something like d'Espagnat's view.

//also consider that the ‘material substratum’ is nowadays regarded as being of the nature of fields in which particles are ‘excitations’. I think this is why Berkelian idealism keeps being mentioned in this context.// — Wayfarer

Well, 'excitations' could not be 'ideas', however. On the other hand, contemporary physics tells us that physical reality is quite different from what it seems to us at the most fundamental level anyway.

Berkeley, by contrast, accepts that there are regular sequences among ideas (what we might call “natural causes”), which God has ordained as the stable framework of experience. These patterns aren’t illusions; they’re effective causes in the world as God presents it to us. — Wayfarer

One might ask, however, how one that endorses an 'idealist' position that flatly denies the existence of some kind of material substratum can explain the regularites (and 'intersubjective agreement') without assuming the existence of God or some God-like being. Of course a theist would not have much problems but a non-theist would perhaps see this as a problem of idealism.
For instance, I always found Kant's arguments to explain intersubjectivity and regularities without appealing to some 'reality beyond phenomena' as insufficient. Of course, Kant posited some kind of unknowable reality beyond phenomena. But still IMO Berkeley at least gives an account on how we might explain the 'order' of phenomena.

This is why I think in another context he could have been something like a logical positivist. — Apustimelogist

It is not surprising IMO. Logical positivists actually are the result of a tradition that goes back to the Empiricists in the Enlightenment, especially David Hume. But Hume was inspired by Berkeley and Locke before him. Then, of course, we have the 19th century positivists like Mach and, finally, the logical positivists.

But note that empiricists, idealists and positivists till the 19th centuries were inspirations of many physicists in the 20th century who weren't logical positivists. These include the 'fathers' of QM but also someone like Einstein.

The OP mentioned that 'idealism' has been influential and a source of inspiration for recent scientific discoveries (even when criticized). I would say that on this point the OP isn't wrong.

But specifically for Berkeley, as an Immaterialist, he does not believe in a world of material substance, fundamental particles and forces, but he does believe in a world of physical form, bundles of ideas in the mind of God. — RussellA

I agree! I would add that then those ideas are also present in the minds of humans (and other created spirits) when the latter percieve the former. And God is the one who assures that our minds perceive the correct of those ideas at the proper times.

In many contexts physical and material are synonyms. Asserting that a mental content is 'physical' can be potentially misleading. I do understand why the SEP article does that but it is according to Berkeley everything is either minds or mental contents. I doubt that, say, also many physicalists would accept to call 'physical' something which is a mental content.

Yes, I agree that Berkeley's target were secular materialists of his day.
But IMO he used the empiricists' arguments (e.g. Locke) to show that phenomena are entirely mental and an external substratum was unnecessary.

However, it is quite different from what traditional theism says on matter. In that system we are acquinted with some features of the physical world. It is a type of direct (yet not naive) realism from our perspective. Of course, given that theism posits that everything is created by God, ultimately it is all ontologically dependent on the Mind of God.

Berkeley IMO took away the 'physical' using empiricist arguments. But in doing so he pointed to God as an explanation why there is intersubjective agreement, regularities in phenomena and so on.
IIRC, he also criticized other theists because, according to him, positing an external material substratum for phenomena 'weakens' so to speak God's role.

The problem is always that ‘mind’ is outside a Wheeler’s usual term of reference. But Andrei Linde doesn’t hesitate to speak about it. — Wayfarer

Agreed. Wheeler, Bohr, Dirac etc were all ambiguos. One feels like they didn't want to assign mind a role but it is not too difficult to see it as an implicit conclusion of their reasoning.

Others like Linde, the QBists etc are not. IIRC, even John von Neumann wrote that the 'self' was responsible for collapse.

QM itself is basically silent. You are free to consider whatever you want to be an observer IMO. But the formalism does suggest that while you can apply QM to anything, you can't describe everything at the same time quantum mechanically - something must be described classically (I believe some physicist made a famous quote that says this).

But I don’t think that the corollary of that is that non-perceived objects cease to exist. They exist in the sight of God — Wayfarer

IMO it is more like God 'sends' to our minds (spirits) the right phenomena (mental contents) we have to percieve in a given time.

I have always asked myself how Berkeley's position fits (if it does) with traditional theistic metaphysics. Maybe some resident expert of that traditional view could explain this but I can't. To me Berkeley's view is something like traditional theism minus the physical world (which becomes entitely mental contents) but I am not sure. But I read about him many years ago.

When one begins to say that 'measurement' is not a name for 'any physical interaction' (like RQM for instance does) but to mean something more complex, yeah it is not a stretch to think that 'mind' has some role.

I do believe for instance that Wheeler's view implies (perhaps unintentionally) a role of the 'mind'.

John Wheeler, 'Law without Law' — Wayfarer

IIRC John Wheeler is a good example of how sometimes physicists themselves provide writings that can be difficult exercises of exegesis, so to speak.

In the extract you quoted, for instance, Wheeler equates the terms 'registered' and 'observed' and this suggests that, according to him, mind is not necessary to 'collapse' the quantum statee. A registering device perhaps is also able to do that.

Two comments here:

(i) one can also say that the content of these 'recordings' become menaingful only when a mind gets to know them. If this is true, one would say that perhaps Wheeler's position implies idealism. Also, registering devices are human made so the activity of the mind actually might be considered a precondition for uniderstanding of their recordings.

(ii) even if (i) is wrong, however, the 'hard realist' objection of John Bell in his Against Measurement:

It would seem that the theory is exclusively concerned about ‘results of measurement’, and has nothing to say about anything else. What exactly qualifies some physical systems to play the role of ‘measurer’? Was the wavefunction of the world waiting to jump for thousands of millions of years until a single-celled living creature appeared? Or did it have to wait a little longer, for some better qualified system . . . with a PhD? If the theory is to apply to anything but highly idealised laboratory operations, are we not obliged to admit that more or less ‘measurement-like’ processes are going on more or less all the time, more or less everywhere? Do we not have jumping then all the time?

actually doesn't fare better if, instead of living or conscious beings, registering devices are those needed to collapse. In fact, it would be still quite strange that a complex inanimate physical object is necessary for the collapse. The world would still have 'waited' a lot to 'collapse'. If the world still had to wait in this case, why not waiting a bit more?

So, those views according to which a real collapse (not just 'decoherence') happens when some complex physical objects do not seem truly better for scientific realists than those which involve some kind of 'mind' (and as I said elsewhere, generally nowadays those who do say that mind has a role in collpase generally interpret collapse in a purely epistemic way, just as an update of knowledge/degree of belief and not that the mind has a 'causal effect' on a real object called 'wavefunction').

Kant doesn’t say our faculties impose order on “reality in itself” — only on the raw manifold of intuition as it is given to us. The in-itself is the source of that, but its true nature remains unknowable; what we know is the ordered phenomenal field that results from the mind’s structuring of the manifold of sensory impressions in accordance with its a priori forms and concepts. — Wayfarer

The problem is if you claim that the reality beyond/prior to phenomena is completely unknowable you have either to accept (i) that the activity of the mind in ordering experience is enough to explain the order we see in phenomena or (ii) that (i) is false and you can't explain how the order we see arises. (ii) would be a form of skepticism. Both are forms of transcendental/epistemic idealism but only in the first option you do have an explanation of the regularities we see.

I'm aware that D'Espagnat differed with both Kant and Berkeley, but he did mention both. Berkeley's idealism is often mentioned by physicists as representing a kind of idealism that they wish to differentiate themselves from. But the point is - he's mentioned! — Wayfarer

Yes, certainly Kant and Kantians did have an important role. They provided arguments that helped even those that, at the end, disagreed. As I said, I agree that also thanks to Kant and so on, we now are more aware about the interpretative role of the mind and we are more aware that 'what appears to us' might not be 'what is really there'.

What Berkeley objected to was the notion of an unknowable stuff underlying experience — an abstraction he believed served no explanatory purpose and in fact led to skepticism. His philosophy was intended as a corrective to this, affirming instead that the world is as it appears to us in experience — vivid, structured, and meaningful, but always in relation to a mind — although importantly for Berkeley, as a Christian Bishop, the mind of God served as a kind of universal guarantor of reality, as by Him all things were perceived, and so maintained in existence. — Wayfarer

Yes, according to Berkeley phenomena are mere appearances. There is nothing 'more' than 'what appears' to the mind. But notice that Berkeley explained things like (i) the intersubjective validity of empirical truths (e.g. scientific truths but not only that), (ii) persistence and stability of the 'world' (e.g. why, say, there aren't drastic changes of what we experience from a day to the following), (iii) the regularities of the 'world' (e.g. 'laws' of physics) and so on by appealing to God. God assures that we, both individually and collectively, have a consistent experience.

Kant, however, didn't want to explain any of the above by appealing to God. In fact, he said that it is the structure of our mental faculties that give us a structure, regulated etc phenomenal world becuase our minds condition appearances to have some characteristics. Since, however, appearances could not be generated completely by the subject, Kant still assumed that there is a non-phenomenal reality but it is unknowable. This unknowability is the reason why Kant isn't regarded as a 'realist' but as a 'transcendental idealist'.
The main problem with this, however, is that there is no sufficient evidence for us to claim that the stability, regularities etc can be wholly explained by the role that the mind has in 'ordanining' appearances. Same goes for intersubjectivity. It is not enough to say that we have 'similar minds' to wholly explain why the 'phenomenal world' appears similar to all of us. Furthermore, if the 'reality beyond/prior to phenomena' is unknowable, how could our cognitive faculties be able to 'order' appearances in the first place?

Notice that d'Espagnat disagreed with Kant here. In fact, he did believe that we can know, albeit partially and confusedly, the reality beyond phenomena (as 'through a glass darkly' to use a Biblical expression in a different context). Such a reality is veiled but not entirely inaccessible. Just like we can know in part and in a confused manner the features of a veiled statue by touching it, in the same way by studying phenomena, according to d'Espagnat, we can know the 'veiled reality'. So, while d'Espagnat's philosophy has many similarities to Kant's, they differ and, in fact, d'Espagnat's position is realist - a realism that, of course, share many things with transcendental idealism (and quite likely influenced by it) but still a realism (of a very paticular kind).

A similar thing is seen among cognitive scientists IMO. They recognize the ability of the mind to 'give a structure' to experience. The mind isn't a passive recorder of 'what happens' but an active interpreter. But IMO they do not go as far as Kant.
I agree, however, that transcendental/epistemic idealist philosophies did influece cognitive scientists (and not only them... undoubdetly they influeced also various physicists, especially starting from the 20th century). So, the importance of these philosophical approaches should not be understimated. In fact, I do believe that they can be (and had been) a source of inspiration for discoveries.


(Good OP btw)

You can see a pdf file of John Bell's article about 'local beables' here: https://cds.cern.ch/record/980036/files/197508125.pdf

No two experiences, whether NDEs or everyday perceptions, are ever exactly identical, even among people sharing the same event in the same moment. Even witnesses at a car accident: Their accounts vary based on vantage point, attention, emotions, and memory, yet the core facts often align. — Sam26

Yes, I agree. I was questioning if with NDEs we get the same degree of agreement that we can, confidently, assume that people witness the same 'experience'. But you are right, we can't expect to have perfect agreements between reports in any case.

This subjectivity is a hallmark of human consciousness, and it applies powerfully to NDEs. Research consistently shows that while NDEs share striking similarities (suggesting a possible universal mechanism), individual differences go beyond cultural backgrounds, influenced by personal psychology, expectations, neurobiology, and worldviews. — Sam26

Can all the differences in the actual experiences be explained by the differences among the subjects?

A 2024 Taylor & Francis review of NDEs across cultures and history found high similarity in features like out-of-body experiences (OBEs), encounters with light or beings, life reviews, and feelings of peace, appearing in approximately 60-80% of global reports. These similarities hold even when controlling for cultural expectations (e.g., Westerners might see Jesus, while Easterners describe Yama, but the "being of light" archetype persists). This is not unusual; it happens in our everyday experiences, too. — Sam26

Thanks for the reference, I'll try to check it.

To make an example to clarify my point... Let's say that Alice has a peaceful NDE where she has a life review, encounters some luminous spirits in a meadow which seems 'more real than real' and, then, encounters a 'supreme being of light'. The, Bob also reports a peaceful NDE where he gets the life review, encounters some spirits in a meadow that also he describes as 'more real than real' and, then, encounters a 'supreme being of light'. When, however, questioned further, Alice says that her review was also in the perspective of other people but this isn't true in the case of Bob. Also, let's say that you find out differences in the characteristics of the 'meadows' they 'saw'.

To me, even if we assume that they visited a 'realm' of sorts, they clearly had 'visited' different 'places'. It's not just that they identified the 'deity' according to their background but they had different experiences. So, I would not say that they are like two witnesses of a car accident or like two people that give an account of their journey to the same city (in the same time period).

Given these problems, can we consider the testimonies as reliable data to arrive, inductively, at some conclusions about, say, the presence or absence of an immortal soul, the characterstics of the afterlife and so on?

Note that I do not come from an 'a priori skepticism' or anything like that. But generally, I see an agreement about the themes (which of course might well be evidence of something important) but I have doubts that the 'harmonization' of these accounts gives a reliable 'theory' about 'how the afterlife looks like'.

Everett's thesis had to dumb-down the number of bases due to the finite but inexpressibly large actuality of the actual figure. — noAxioms

IMO not just for that reason, but also because he had to explain how 'classicality' arises.

Hence Rovelli saying that a thing cannot measure itself, it can only measure something sufficiently in the past to have collapsed into a coherent state. — noAxioms

Ok. I thought that he said that a thing can't measure itself becuase a thing can't interact with itself. Interesting.

'beable'. — noAxioms

The term 'beable' was introduced by John Bell as opposed to 'observable'. Basically, 'beable' were objects or properties that are definite (i.e. that can be represented mathematically with definite quantities) even if there is no measurement. Local realists, like Einstein, hoped to explain everything in terms of 'local beables' (like, say, point particles, local values of fields and so on) which interact with local interactions (i.e. interactions that aren't faster than light). Of course, what Bell proved is that you have either to assume that, ultimately, there are no 'beables' in the sense expressed above or that, ultimately, there are 'nonlocal beables' or at least beables that interact with faster than light interactions.

@Sam26, I also find NDEs fascinating and I am interested in your research.
Quick question... NDE reports show a remarkable convergence of 'themes' and descriptions among people of different cultures, life experiences and so on.
It seems to me, however, that there is no evidence that two NDEs can be exactly the same. That is, they can be very similar and this is quite interesting. But IMO from the accounts I have read, the reports show differences that can't be explained only by referring to their different cultural backgrounds. So, I would say this might raise skepticism for taking these reports literally as in the case of, say, two people that travel to the same city and then give you the account of that journey. A guess that my question is: do we have sufficient evidence that these experience give us 'faithful' descriptions of the same 'reality' and not dscriptions of similar yet ultimately different 'realities'? This doesn't seem to be a point that is addressed with sufficiently depth in other works on the topic I read.

Of course, this doesn't necessarily imply that NDEs are completely non-veridical and cannot serve as reliable testimonary evidences. Still, I wonder in your view how these subtle differences are to explained.

I don't understand any of that. There is no right/wrong basis under MWI. They all share the same ontology, but some are more probable than others, whatever that means. — noAxioms

No worries, as I myself said it is a quite secondary issue. Even if there is a counter-intuitive increase of number of 'bases' it is not a problem, I guess, for MWI-supporters as they already accept that there many more 'worlds' out there.

Thanks for the patience!

Ok, I see thanks for the clarification. To me, however, all this means that Nietzsche believed in some 'objective' morality of some sorts. If there are 'sick' and 'heal' ways in which the will can express itself and we can know this, it seems to me that an objective or at least 'inter-subjective' basis for ethics/morality (i.e. 'how to live'). This would mean that Nietzsche wasn't a relativist after all, despite what sometimes he claimed and what how some interpreters read him.

Also it is useful to remember that not all 'objective ethical theories' consider ethics as a purely extrinsic set of rules with no relation to our 'nature'. In fact, many of them regard 'ethical rules' as a way to 'heal' the will or to express the will in a 'healthy way'.

I think that many of Nietzsche criticisms apply to ethical systems where ethics is a purely extrinsic set of rules. It is questionable if they really apply to other ethical systems.

They are nowhere near sufficiently significant. I cannot think of a scenario, however trivial, where you'd see this. It would be the equivalent of measuring which slit the photon passed through, and still getting an interference patter. Interference comes from not knowing the state of the cat, ever. — noAxioms

Yeah, I was just wondering if their magnitude is small 'enough' after measurement/interaction. Some years ago, I read that there was some debate on this point.

Sure we do. You observe that by not measuring the spin, same as not measuring which slit. — noAxioms

I meant that the 'normal' basis is selected, after the measurement, due to the fact that our experimental apparatuses are structured in some ways. In other words, the reason why we observe things in the 'right' basis is that the the experimental apparatus has those properties it has. However, in principle, you could have that after the measurement the state vector 'collapses' to one of the vector in the 'wrong' basis.

But, again, it is perhaps an useless observation. No theory in physics, after all, explains why the world is structured in the way it is. So, MWI is perhaps also immune by this 'criticism'.

Well, sort of what you say about Schopenhauer.
By 'voluntarism', I mean a position that gives prominence to the will. So, for instance, the mere ability to excercise the will is 'freedom' in a voluntaristic system. I'll try to clarify what I meant by talking about the concept of freedom.

So, the mere ability to act in concordance with the will is what 'freedom'. Morality, according to Nietzsche, hinders that ability by constraining it with rules and this is why it is so bad. As I understand him, imposing on ourselves and others 'moral rules' suffocates disables the ability to act according to the will. Rather, Nietzsche would suggest, we should accept to live without putting constraints on the will and accept the suffering that such a way of life entails (due to, say, the conflict that inevitably happens).

This is clearly a different understanding on the ancient model of freedom (that you can find both in non-Christian and Christian philosophers of that time) according to which, in the case of rational beings, only a will that knows the 'good' is truly free and finds fulfillment. Nietzsche would say that such an understanding of freedom because all modes of willing, if they are not constrained by something else, are 'good'.

If this clarification didn't help, try to read my previous response ignoring the adjective 'voluntaristic'. I don't think that it is essential to understand what I wrote.

Why would you want interference removed? It is seen. Even a realist interpretation like DBB has the photon going through one slit and not the other, yet interference patterns result. We experience that. Perhaps we're talking past each other. — noAxioms

Yes, I think so. Probably it is because also I am muddlying the waters lol.

Anyway, my contention is that if the interference terms are too significant, in the Schrodinger's cat experiment, the version of the observers that sees the 'alive' cat should perceive in some ways the other 'world'. I get that decoherence explains that, due to the decoherence between the observer and the system you get definite outcomes but IMO one also needs that the interference terms become negligible to get the appearance of classicality (i.e. 'definitiness').

Hope I clarified a bit.

You don't know that, there being no evidence of it. Under MWI, there's no 'our', so every basis is experienced by whatever is entangled with that basis, with none preferred. — noAxioms

I disagree. In my example of spins, for instance, we observe either '+1/2' or '-1/2', but we never observe the state 1/sqrt(2)('+1/2'+'-1/2'). In other words, I am not sure how, in MWI, from 'first principles', without the assuming from the start that MWI must be consistent with our experience, we can derive the classical features that we observe.

Anyway, this is not an important point. I mean, perhaps it is asking too much.

Also, for the 'voluntaristic' part, I disagree but I admit that his voluntarism is quite strange as he questions the existence of the 'agents' that will or, as you say, see the agents as fragmentary.

In any case, he IMO was pretty clear that all geniune manifestations of 'life'/'will to power' were 'innocent', like an innocent play, and morality (whether religious, civil etc) was something that constrained the manifestion of that innocent play. Nietzsche was, of course, aware that in the world these 'plays' inevitably conflitct (both in the natural world and among humans). Conflict is inevitable but for Nietzsche this is not a bad thing. It is actually good (if it is not motivated by some kind of 'morality' or 'resentment' that constrains the will to power).

Clearly he was inspired by Heraclitus, e.g. (see here: https://en.wikisource.org/wiki/Fragments_of_Heraclitus ):

Time is a child playing draughts, the kingly power is a child's (fragment 52)

War is the father of all and the king of all; and some he has made gods and some men, some bond and some free. (fragment 53)

We must know that war is common to all and strife is justice, and that all things come into being and pass away (?) through strife. (fragment 80)

Already in 1873 in his unpublished work 'Philosophy in the Tragic Age of the Greeks' Nietzsche contrasted Heraclitus with Anaximander by saying that Anaximander thought that the conflict between extremes was an 'injustice' whereas Heraclitus viewed it as the expression of 'justice' (strife is justice).

Why I believe it is 'voluntaristic'? Because Nietzsche didn't distinguish between good ways in which life manifests itself and bad. Simply, whatever the will wills is good. The only bad thing is to hinder the manifestions of the will.

The ability to predict how everything will deviate from the proposition doesn't make the proposition true. That everything deviates from the proposition indicates that it is false. The usefulness of it, I do not deny. — Metaphysician Undercover

Or perhaps... it shows that it is approximately true. As I said, I think we have to just agree to disagree here. For me it is OK to say that some understanding of reality can be 'approximately true'. For you, apparently, either a statement has a perfect correspondence with 'reality' or it is simply false. I do believe, instead, that some statements can be 'partially right'.

The truth they say is 'I am false'. — Metaphysician Undercover

I disagree.

This didn’t mean that he abandoned all possibilities of distinguishing what is a better way of life from what is worse. What he did was to separate this issue from the particular content of meaning of specific value systems. — Joshs

Right. But what is the 'basis' of the 'better' or the 'worse'? Here's what, for instance, Nietzsche said in Beyond Good and Evil, 259:

259. To refrain mutually from injury, from violence, from exploitation, and put one's will on a par with that of others: this may result in a certain rough sense in good conduct among individuals when the necessary conditions are given (namely, the actual similarity of the individuals in amount of force and degree of worth, and their co-relation within one organization). As soon, however, as one wished to take this principle more generally, and if possible even as the FUNDAMENTAL PRINCIPLE OF SOCIETY, it would immediately disclose what it really is--namely, a Will to the DENIAL of life, a principle of dissolution and decay. Here one must think profoundly to the very basis and resist all sentimental weakness: life itself is ESSENTIALLY appropriation, injury, conquest of the strange and weak, suppression, severity, obtrusion of peculiar forms, incorporation, and at the least, putting it mildest, exploitation;--but why should one for ever use precisely these words on which for ages a disparaging purpose has been stamped? Even the organization within which, as was previously supposed, the individuals treat each other as equal--it takes place in every healthy aristocracy--must itself, if it be a living and not a dying organization, do all that towards other bodies, which the individuals within it refrain from doing to each other it will have to be the incarnated Will to Power, it will endeavour to grow, to gain ground, attract to itself and acquire ascendancy-- not owing to any morality or immorality, but because it LIVES, and because life IS precisely Will to Power. On no point, however, is the ordinary consciousness of Europeans more unwilling to be corrected than on this matter, people now rave everywhere, even under the guise of science, about coming conditions of society in which "the exploiting character" is to be absent--that sounds to my ears as if they promised to invent a mode of life which should refrain from all organic functions. "Exploitation" does not belong to a depraved, or imperfect and primitive society it belongs to the nature of the living being as a primary organic function, it is a consequence of the intrinsic Will to Power, which is precisely the Will to Life--Granting that as a theory this is a novelty--as a reality it is the FUNDAMENTAL FACT of all history let us be so far honest towards ourselves!

So, it seems to me, that for Nietzsche whatever 'favours' the expression of the 'will to power', which he equated with 'life', is 'good' and whatever 'hinders' the 'will to power' is 'bad'. Right here we have Nietzsche making quite an 'absolute' statement about what is 'good' and what is 'bad'.
Morality, religion and so on were wrong for Nietzsche becauese, according to him, they hindered 'life'. Due to the fact that 'life' is often difficult, there is conflict in the world and so on, according to Nietzsche many (all?) religious figures, for instance, sought and taught a 'way to liberation' or 'salvation'. For him this is 'bad' because, in fact, they were trying to hinder the expression of life.

So, I'm not sure that Nietzsche was actually a 'relativist' in the way he is often depicted. But, at the same time, he also thought that this world is in flux and there are countless ways in which the 'life'/'will to power' can manifest. So, the creative artist is a perfect example of how the 'will to power' can manifest and hindering the artist is hindering the will to power. But also the conqueror, the social reformer and so on can be manifestations of the 'will to power' (this doesn't imply that Nietzsche was a monist or a pantheist/panentheist of some sorts, as the 'will to power' might not be a single entity. Interestingly, however, in his notebooks made a statement that suggest precisely this*).

So, in any case, if what is 'good' for the life can change radically, why, say, some 'life-denying' morality could not, in some times, be a legitimate way of the expression of life? Same goes for resentiment?

Ironically, despite his 'relativistic' fame, Nietzsche seemed pretty convinced that some expressions of human life were just 'bad'. Yet, I agree this is inconsistent with his thesis that this world is a 'radical flux' where nothing is really fixed. But if this 'radical flux' was the 'ultimate truth' in Nietzsche, then this would made a lot of his philosophical analysis (think about his analysis of 'resentment' and the historical importance that it had according to him) at least questionable if not completely empty. There is a tension present in Nietzsche philosophy. I think that this is indicates a deep inconsistency in his thinking: on one hand he wants to affirm that 'good' is what what favours the expression of life and 'bad' is what goes against life. On the other hand, however, his thesis that nothing remains the same, renders such a statement, ultimately, vacuous IMO.

And we can get better and better over time at allowing the creative future to flow into the present. This seems to me to be a promising , growth-oriented way of life. If it is empty, it is only empty of content-based prescriptions, as I think it should be. — Joshs

Where does he say this? I think that one of his 'Untimely mediation' was actually against the idea of 'progress'. And also in later years he didn't think that the future will be 'better' than the present. Could you provide some references?
In fact, it seems the idea that we 'should' seek a 'better future' goes against many things he says. For him, the will to power doesn't have a 'purpose', it is like an innocent play (see the quote below).

*Here's the quote:

That the world is divine play [göttliches Spiel] beyond good and evil―for this, my predecessors are the philosophy of Vedanta and Heraclitus. (NF 1884)

(source, e.g.: https://api.research-repository.uwa.edu.au/ws/portalfiles/portal/49665695/TH19_143_THESIS_DOCTOR_OF_PHILOSOPHY_MILNE_Andrew_William_2019.pdf)

Perhaps. It's been said he has a nihilist view of Nāgārjuna, and this kind of mistaken interpretation is not infrequent even amongst expert readers. — Wayfarer

Ironically, in a sense the problem is the opposite, i.e. he still 'reifies' too much things and leans toward a physicalism that is not very compatible with the views of Nagarjuna. Ultimate truth is beyond concepts and it is also presented as saying that, ultimately, things 'do not arise'. Appearances aren't negated but they are seen as mere apperances, neither true nor false, like 'moon in the water' as Nagarjuna compared conditioned things in his Sixty Stanzas of reasoning.
I do believe that Rovelli's views are similar to the 'conventional truth' espoused in Buddhist traditions. Interdependence is central also in RQM but in Buddhism one goes beyond that.

Have you encountered the charming and ebullient Michel Bitbol? I learned of him on this forum and have read some of his articles. He is a French philosopher of science who has published books on Schrodinger, among other subjects. Also has an expert grasp of Buddhist philosophy. See for example It is never Known but Is the Knower (.pdf) — Wayfarer

Yes! Bitbol is an excellent source. Notice that he is also closer to QBism than Rovelli's RQM. I also believe that they are good friends.

There are convergences between Buddhism and physics, but they're nothing like what you would assume at first glance. It has to do with the ontology of Buddhism, which is not based on there being Aristotelian substances or essences, and also on the way that Buddhism understands the inter-relationship of 'self-and-world'. It has a relational, not substantial, ontology. Husserl sang high praises of it. — Wayfarer

Agreed!

Thanks for the clarification.

1. Life, in general, is eternal. Not life of one particular individual, but in general. — kirillov

This is a questionable premise. Scientific evidence, in fact, suggest that life 'in general' will end. But I am open to think that science might not tell us the whole story here.

So, for the sake of the discussion, let's say that you are right.

2. Life is suffering. One's life, by pure luck, can be pretty good in absent of pain in suffering. But that's not the case overall. — kirillov

Again, you are assuming that all instances of life are just like this. I believe that you reject those views that tell that there is a reasonable hope (for them) that there will be a better state.
Again, I'll grant you the validity of the premise to see where we go.

3. Life cannot be escaped. — kirillov

OK.

And the problem is: how one, given three premises above, affirms life as it is? — kirillov

OK. Honestly, I would say it depends on the ability that the 'living beings' might have to control and reduce the amount of purposeless suffering, i.e. suffering that doesn't lead to something postive.
If, however, life will be always in a situation where negative states overcome positive states and there is absolutely no hope to change that, I would say that one can't rationally affirm 'life'.

So if your three premises are right, then, no, I would not think that it would be rational to affirm life, as it is irrational to affirm a state dominated by purposeless suffering.

What about Nietzsche... I don't want to discuss him at this thread, because that's not the point of it.
And my interpretation of him radically differs from mainstream — kirillov

Ok!

For me, life (in general) isn't finite. In Buddhist word's, Samsara will make another turn. — kirillov

Ok. But notice that religions that accept samsara generally posit some kind of transcendence of the transitoriness, suffering, death present in it. They do not 'affirm life' by accepting death, suffering etc but they generally try to find a 'way out'. That's why detachment is generally a common attitude you find in them (as well as compassion for other beings trapped in the prison of samsara).

And there's situations where you can't avoid/moderate pain & suffering (that's what I'm dealing with) , so Epicurus is not for me. — kirillov

Agreed. But in a purely 'secular' worldview, I would say it is the best approach. Suffering can't be eliminated or even reduced in certain circumstances and, in fact, Epicurus also suggested to find way to make it more bearable.

I find Epicurus' philosophy depressing in a way but I do think that given the assumptions of his worldview is the most rational.


FWIW, I am sorry for your situation BTW. I hope it will get better.

I know that suffering is unavoidable. As I said: "life is eternal suffering".
My goal is to affirm it, accept it. To love this life despite all the suffering it entails. — kirillov

Well, as I said, religions that accepted samasara generally tried to escape and not 'affirm' samsaric life. If we are indeed in samsara and we can't transcend it, I think that 'affirming' it inevitably will make samsara worse. We can't transform samsara in a positive state.

There is a reason why historically the 'escape' from samsara was put in term of knowing a 'higher reality' and/or recognizing that is a sort of illusion and so on rather than try to see it in a more 'affirming' way.

It would just mean that the theory is completely useless. If a necessary condition of the theory is perfect conditions, and it is demonstrated that perfect conditions are impossible, then the theory can be dismissed as useless, because that premise can never be fulfilled. — Metaphysician Undercover

I feel that we are going to have to agree to disagree here. Perhaps there are no isolated systems but the law of conservation of energy had been incredibly useful and, in fact, you can deduce the deviations and confirm them experimentally.

It's not the law of conservation which produces consistent predictions, as is obvious from the fact that it is inaccurate. Predictions can be produced from statistics, and the statistics might concern deviations form the conservation law. Then the conservation law would not state anything true about the world, it would just be a useful tool for gathering statistics. — Metaphysician Undercover

Galileo discovered that, without the friction of air, falling object would move under the influence of gravity with an uniform rettilinean accelerated motion. Still, here on Earth we can't be without air (except in some void chambers) and, therefore, the conditions of free-fall are not met. Does this mean that Galileo was simply wrong?

Approximation is key in physics. Same goes for idealizations. The same goes for the awareness of the limitations due to them.

Isn't that exactly what we are debating, whether the conservation law is true or false? You've already decided that it is merely approximate, why not take the next step, and accept that it is false? — Metaphysician Undercover

Because I believe that even if there are no isolated systems, the usefulness of the laws prove to me that they do tell something true about the 'order of nature'. To use out of context St. Paul's phrase "we see through a glass darkly", but we aren't blind.

That's exactly what measuring the temperature is, work being done. The energy acts on the thermometer, and this is an instance of work being done. Therefore taking the temperature is an instance of work being done. — Metaphysician Undercover

Even if the thermometer responds due to the work that the particles of the constituent do on it, you can't convert all the heat transferred via e.g. friction in a thermometer and then use that stored energy to do work again. The second principle of thermodynamics just says that: it is impossible to have total control of energy.

QM doesn't have a reduction postulate, but some of the interpretations do. Each seems to spin the role of measurement a different way. — noAxioms

Yes. In order to get definite outcomes without interference you need that axiom (or some modifications of the mathematical apparatus of QM as in dBB)

It seems to be enough given an interpretation (MWI say) that explains it that way. — noAxioms

MWI was developed before decoherence. MWI supporters like decoherence because it seems to explain the branching. It doesn't IIRC remove interference however. I believe that it is legit to ask if it is 'enough' to explain our experience.

Interference is a statistical effect, so with no particle can interference be measured, let alone measured by the particle in question. But it can be concluded given hundreds of thousands of objects all being treated identically. So I suppose a really huge crowd of people (far more than billions) could collectively notice some kind of interference if they all did something identical. I cannot fathom what that experiment would look like or how any of those people could survive it. — noAxioms

Ok. But this still doesn't refute my point. It is conceivable to observe interference it it exists. So, perhaps, some versions of MWI are falsifiable?

So the cat is in superposition of the interior definite state of being dead and alive, but the cat is not in a exterior definite state, meaning it is still in superposition relative to the lab. And yes, they can measure interference in principle. — noAxioms

But in this relationalist view, the basis is selected via the experimental apparatus. In MWI one should IMO expect to derive everything from the universal wavefunction. I don't think that your view is affected by that argument.

There's no preferred basis in MWI. That much I know. Can't speak for MMI. — noAxioms

Yes, but there is a preferred basis in our experience. How does MWI account for that? Here what Schwindt concludes:

I have shown that it is always possible to factorize the global Hilbert space into subsystems
in such a way, that the story told by this factorization is that of a world in which nothing
happens. A factorization into interacting and entangling subsystems is also possible, in
infinitely many arbitrary ways. But such a more complicated factorization is meaningful
only if it is justified through interactions with an external observer who does not arise as
a part of the state vector.
The Many World Interpretation is therefore rather a No World Interpretation (according to the simple factorization), or a Many Many Worlds Interpretation (because each of
the arbitrary more complicated factorizations tells a different story about Many Worlds
[7]).

So, perhaps, there are 'Many-Many Worlds'...

(This has been explored by credible academic sources, moving beyond popular mysticism, to examine genuine philosophical parallels. Theoretical physicist Carlo Rovelli, founder of loop quantum gravity, has written seriously about how Nagarjuna’s philosophy of emptiness—the idea that phenomena lack intrinsic existence—resonates with quantum mechanics’ relational ontology, where particles and properties exist only through measurement relationships rather than independently. Academic journals have published rigorous analyses, such as SpringerLink’s examination of “Two Aspects of Śūnyatā in Quantum Physics,” which argues that both quantum mechanics and (Middle-Way) Buddhism suggest there are no intrinsically existing particles with inherent properties, but rather that all phenomena arise through dependent relationships. This philosophical convergence centers on the idea that reality is fundamentally relational rather than consisting of purportedly mind-independent objects, challenging the classical scientific assumption that the objective domain has fixed, determinate properties independent of observation. It dovetails well with aspects of the Copenhagen and QBist interpretation, not so much with classical realism.) — Wayfarer

Notice that Rovelli IMO overstates the similarities. Yes, his interpretation has a lot in common with Madhyamaka. But Madhyamaka has an (epistemic) 'idealistic' bent to it that Rovelli doesn't capture. Ultimately, all apperances are illusion-like or equivalent to illusions. I doubt that Rovelli would agree with that. QBism perhaps is closer to Madhyamaka but perhaps QBism risks to reify 'agents' in a way that Nagarjuna would not have approved.

Still, I am happy that physicists find inspiration in those views. It might mean something... not sure what but I don't think that it doesn't mean anything.

Yeah, I see that I also went on to comment excessively on Nietzsche's philosophy. Anyway, in the first paragraph of my response I pointed out that, in my opinion, kirillov sought to find a way to affirm life in the same degree as Nietzsche did if there is no possibility of transcendence and/or ultimate redemption. If that is what they were asking, I believe that a more rational way to approach life would be something like the Epicurean model. That is cherishing and delighting in life in moderation, i.e. we should remind ourselves that life is finite and try to avoid to attach to it too much importance. — boundless

Also, if death means the definitive separation between people that are dear to us, the rational way to process the separation is with grief. Because by grieving we recognize the intrinsic value of these persons and we recognize that value is now irrimediably lost. So, it would seem that without any hope of transcendence and/or redemption it is impossible to avoid to suffer and attain any kind of solid happiness.

Folks keep posting thoughts and comments about Nietzsche or Schopenhauer when the OP clearly stated that their philosophy no longer satisfies him. So, there is no solution for the moment. He just asked us what to read now, not what you guys think about these German boys. :grin: — javi2541997

Yeah, I see that I also went on to comment excessively on Nietzsche's philosophy. Anyway, in the first paragraph of my response I pointed out that, in my opinion, @kirillov sought to find a way to affirm life in the same degree as Nietzsche did if there is no possibility of transcendence and/or ultimate redemption. If that is what they were asking, I believe that a more rational way to approach life would be something like the Epicurean model. That is cherishing and delighting in life in moderation, i.e. we should remind ourselves that life is finite and try to avoid to attach to it too much importance.

I do believe that, if there aren't any kind of trascendence and/or redemption, ultimately, life is quite a tragic endeavour where death has the 'last word'.

To assume that one could impose a criterion for the goodness of a value system, the ‘best way’ to affirm life, from outside of all contingent perspectives, a god’s- eye view, view from nowhere or sideways on, is to impose a formula which is meaningless. In Nietzsche’s sense such aesthetic ideals are the definition of nihilism. And given the fact that most of the suffering in this world comes at the hands of those who act on behalf of supposedly perspective-free principles and criteria of truth and righteousness, it may be time to think differently. — Joshs

While I would say that there are some things that are always morally good or bad, I also think that in some cases it is context dependent. Anyway, my point is different.

If, according to Nietzsche, all manifestations of life are manifestations of the 'will to power', and there is no ultimate 'right' or 'wrong' way to manifest it (someone in the classical tradition would perhaps say that the 'right' way is what fulfills the nature of the will, but Nietzsche rejects that), it is somewhat inconsistent to write books glorifying some way of living and criticizing others. You would expect that Nietzsche would say something like: "ultimately, there are different forms of the will to power. There is no good or bad ways to express such a willing/power. So, do what you want to do without any 'moral' concern!". Instead, he wrote many books to show how inadequate were religions, especially Christainity.

Mind you, I think that Nietzsche had pretty interesting things to say (e.g. about how resentment works and can condition our thoughts, about creativity and so on). But his extreme 'voluntarism', expressed in his mature 'amoralism' and 'will to power' etc is IMO more consistent with an empty philosophy rather than a philosophy that can teach a 'way of life'. To put it differently, the 'pars destruens' was so pervasive than no 'pars construens' seems consistent with it, not his.

If there is no transcendence of and/or redemption from transitoriness, suffering and death, however, I don't see how and why we should 'affirm' life at the level that Nietzsche would like. We can certainly cherish life but it is also true that without any form of transcendence death has the 'last word' so to speak both for the individual and for our species. Life is a completely tragic phenomenon and the tragedy is amplified the more we affirm it. If we affirm it like 'tragic heroes', it doesn't change the fact that, however, 'death wins'.

Furthermore, the problem with Nietzsche's philosophy is that it is inconsistent here IMO. If the 'highest form of life' is a life where we impose our values and there is no critierion in which we distinguish, in a non-arbitrary manner what is the best way to 'affirm life' then a 'life affirming' stance is no 'better' than a 'life denying' one, as both are said to be manifestations of the 'will to power'. Why should a manifestion of the will to power be better than another if there aren't criteria to tell which is better? In other words, I do not see in Nietzsche's philosophy enough convincing arguments for avoiding a compeletely arbitrary stance of life where absolutely any stance is no better or worse than any other.

I do not think that your claim is reasonable. No experiment has provided 100% conservation, so it is actually unreasonable to say that results are consistent with conservation laws. For some reason, you think that stating that the law is an "approximation" makes the law reasonable. What if I told you that 9 is approximately 10, and so I proposed a law that stated 9 is always 10? Would it be reasonable to claim that this approximation justifies the truth of my law? I don't think so. Why would you think that approximation in the case of the law of conservation of energy justifies a claim that the law is true? — Metaphysician Undercover

I see what you mean. But suppose that a theory tells you that if the conditions are perfect you get 10 and if they aren't you get 9. You never get perfect conditions and you always get 9. This doesn't refute the theory, far from it!

So, if there is no 'isolated system' and you observe that energy isn't perfectly conserved it is hardly an objection of the law of conservation of energy if it gives consistent predictions also in the cases where it is expected that energy isn't conserved.

Yes, the use of conservation laws does "point to something true about the physical universe". The evidence indicates overwhelmingly, that conservation laws are false. That is the single most important truth that we can abstract from the ongoing use of conservation laws. — Metaphysician Undercover

I disagree. What your objection actually point to is that there are no perfectly isolated systems, except perhaps the universe as a whole. Which is BTW interesting, but it doesn't refute the laws of conservation.

Your objection however does raise the problem of how to interpet the fact that idealizations seem never to find a 'realization' in nature. That's a perfectly fine area of inquiry but is different from what we were debating.

The very act of measuring the temperature is in fact an instance of using that energy as work. — Metaphysician Undercover

Honestly, I am not sure of what you are saying here. When you measure temperature (or internal energy) you don't tranform it to work.

Yes. Enformationism*1 is similar in some ways to ancient World Soul and Panpsychism worldviews. But it's based on modern science, specifically Quantum Physics and Information Science. The notion of a BothAnd Principle*2 illustrates how a Holistic worldview can encompass both Mind & Body under the singular heading of Potential or Causation or what I call EnFormAction. Here's a review of a Philosophy Now article in my blog. :smile: — Gnomon

Interesting, thanks!

From a purely speculative metaphysical perspective, bottom line is, one’s decision on his relation to himself follows necessarily from whether or not the volitions of his will justify his worthiness of being happy. Clear conscience on steroids, so to speak. — Mww

I prefer thinking about these things in a virtue ethics framework, but I think we aren't say different things here. I would say that 'clear conscience on steroids' fulfills our nature...

You'd have to show where QM says anything like that. QM does not contradict empirical experience. — noAxioms

Yeah, I should have phrased it better. I meant something like 'QM without the reduction postulate'. If you do not accept collapse, you still have superposition and interference. So, you need to explain why we do percieve everything in a definite state. Many claim that the 'appearance of collapse' given by decoherence is enough. Others disagree.

Right. There's no cat experiencing superposition or being both dead and alive. There's (from the lab PoV) a superposition of the cat experiencing living, and of experiencing dying by poison. A superposition of those two experiences is very different than the cat experiencing both outcomes. Each experience is utterly unaware of the other. — noAxioms

I know. But I was questioning if decoherence is enough for the appearance of collapse. Interference terms remain, they become however very, very small. Is that truly enough to explain our 'definite' experience (same goes for the cat's experience)?

'Definite states' sounds awfully classical to me. MWI is not a counterfactual interpretation, so is seems wrong to talk about such things. — noAxioms

Definite means something like this. Consider a spin 1/2 particle. When we measure the spin (say) in the z-axis we obtain either '+1/2' or '-1/2'. So, '+1/2' and '-1/2' are 'definite states'. The general quantum state of that particle can be written as a linear combination of these 'definite states'. Let's call this basis 'basis 1'.
But again the same is true for the states '(1/sqrt(2))*('+1/2' +'-1/2')' and '(1/sqrt(2))*('+1/2' -'-1/2')'. These two states are an orthogonal basis but they do not correspond to anything in our experience. Still, a genral quantum state of the same spin 1/2 particle can be written as a linear combination of these two vectors. Let's call this basis 'basis 2'.

Here things go tricky, however. Why, when we make a measurement, does the quantum state collapse or appear to collapse in one state of the 'basis 1' instead of 'basis 2'? Certainly 'basis 1' describes the states that correspond to our experience. But if MWI-supporters do not want to make any reference to experience to explain how we have the quantum-classical transition, then why systems evolve as if they have to appear to collapse in a state of the 'basis 1', which happens to correspond to our experience?

This is a part of, as I understand it, the 'preferred basis problem'. MMI posits that 'basis 1' is selected by the mind. But 'pure MWI' claims to be 'QM without the collapse postulate' and no other additional axiom like the collapse/reduction.

I don't think that this objection is fatal, though. But to me it suggests that there is more in the story than just states in the Hilbert space and their evolution as MWI would claim.

Hard to read, lacking the background required, but it seems to say that there are no 'worlds' from any objective description of say the universal wave function. It has no 'system states', something with which I agree. There are no discreet worlds, which again, sounds like a counterfactual. I think the paper is arguing against not so much the original Everett paper, but against the DeWitt interpretation that dubbed the term 'worlds' and MWI and such. I could be wrong. — noAxioms

Yeah, the paper is a bit technical and also beyond my paygrade. Basically, however, it tries to reject MWI by adducing that if a MWI supporter doesn't add some postulate to 'pure QM without the collapse postulate' you can't explain how the universe decompose in subsystems, how the preferred basis is selected etc. So, I would say that it does apply to any Everettian interpretation with the universal wavefunction. RQM seems unaffected by the criticism.

Yet, QM taken literally tells us that we should perceive an interference of mutually exclusive states. For instance both states of the cat in Schroedinger's (in)famous experiment. In order to avoid that conclusion, decoherence is taken as an explanation of the appearance of 'definiteness'.

Any interpreter of QM must give an account of why we do not experience mutually contradictory states.

Also there is the preferred basis problem. Basically, in MWI the branching is explained by saying that there is a superposition of definite states. Yet, there seems no reason from 'first principles' that tells us that the branching should be between definite states. In fact, it seems an a posteriori assumption that is made in MWI. This is not a fatal objection to MWI but, if I am not mistaken, the fact that the branching happens in the way that is consistent to our experience is a ad hoc assumption that we need to add to MWI.
This problem is found in all interpretations that claim to not add any additional structure to the quantum state of the universe. This objection doesn't apply to de Broglie-Bohm due to the presence of particles and to Copenaghen-like views due to the presence of observers. Also perhaps MMI escapes this problem via the 'minds'.

See on this this paper: "Nothing happens in the Universe of the Everett Interpretation" by physicist J. Schwindt.

@noAxioms

Do you have a solid concept of what the experience of interference would be like? What kinds of experiences would you be expecting, if there were interference? — flannel jesus

I have no idea. That's might be taken as a suggestion that there is no interference in the world we experience. Hence, decoherence is not enough. In fact, I do agree with this.

Conversely, MWI supporters would say that our experience is not precise, has been proven wrong before and, therefore, should not be trusted here.

Yes that what MWI supporters point out. If interference is very, very small it is reasonable to say that it is negligible after all. You don't need a 'perfect classicality' when you have a classicality FAPP ('for all practical purposes' to borrow a phrase of John Bell used in a different context).

Note however that our experience does seem about definite outcomes without any interference, i.e. our experience suggests to us that there is no interference, period. Of course, it can be wrong.

Honestly, I think that it is one of those situations where you get a stalemate between two positions.

Interestingly, you find a similar problem in epistemic interpretations different from QBism vs QBism. Here, probabilities that have a value of 0 and 1 do not represent probabilities, rather they represent the situation when you get a certain knowledge. And from here you get the speculations about a supposed role of observations to bring 'into being' definite outcomes from an indeterminate state. In QBism, probabilities with a value of 0 and 1 still represent a 'degree of belief' like all other probabilities.

I have no disagreement with the idea that the law of conservation of energy is "a very good approximation. But the point is that it is not what is the case. Therefore it is not the truth. — Metaphysician Undercover

I would be careful here. Yes, it seems that there are no perfectly isolated systems, except perhaps the whole universe, but our experiments tell us that when the approximation is reasonable, the results are coherent with conservation laws. Also, when we know the deviations that we expect from a non-isolated system (i.e. when we know 'how much' the system is not isolated), we find a coherent result.
This certainly points to the fact that, at least, conservation laws do point to something true about the physical universe, even if the conditions where they hold without errors are never actualized. Or maybe they are valid when you take the entire physical universe all together.

Furthermore, the conservation of energy (and of linear and angular momenta etc) has been a very good source of discoveries. For instance, in particle physics, the neutrinos weren't observed initially. Some energy seemed to be missing. But the neutrino were discovered.

The point being that "a very good approximation", which leaves aspects of the concept of energy, such as "entropy", accounted for by unacceptable descriptions, is misleading, regardless of whether it is a good approximation. — Metaphysician Undercover

But note that entropy is not a form of energy. Even its physical dimensions (measurement units) are different. Also, there is nothing like an energy-entropy equivalence like there is a mass-entropy equivalence.
Entropy is more like how energy is distributed than a measure of the quantity of energy that is 'lost'.

The point is that if some energy cannot be controlled, then it cannot be detected, because detection is a type of control. And if it cannot be detected it cannot be called "energy". So "entropy" serves as a concept which consists of some energy which is not energy, and that is contradiction. — Metaphysician Undercover

Nope, you can measure the increase of temperature (and hence, internal energy) due to friction. But you can't recover it to use it again as work.

No, I am saying that a perfectly closed system is impossible and the law of conservation of energy is demonstrated as false because it requires a perfectly closed system for its truth. And, this is due to the nature of time, what is known as the irreversibility of time. — Metaphysician Undercover

This is an interesting, if contentious point. But it is unrelated to entropy. If there are no perfectly isolated systems, the law of conservation seem to never hold. But, again, note my points at the beginning of my response.