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The_Sympathizer

 Discussion on answer by John: Can sel…

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The_Sympathizer
Oct 25, 2023 08:38
@KerrAvon2055: Yeah, I removed the comment now because I'm not sure that that term conveyed what I wanted to say. I meant "elite, as in what would be elite in today's population, which might not be considered so in a population where it is far more prevalent, owing simply to its prevalence". Nothing about accepted bodies of theory, but the "raw ability" (if that is even a thing).
 

 Discussion on answer by Flater: Is Pa…

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The_Sympathizer
Jul 12, 2023 12:19
@Kaia : The interesting part/question here is how far beyond strictly "rolling your own crypto" does that go? Because this suggests even using a well-trusted library, alone, would not be sufficient.
 

 Discussion on answer by Flater: Multi…

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The_Sympathizer
Jun 29, 2023 13:56
@Flater : Yes. I wish I'd understood that much longer ago, though.
The_Sympathizer
Jun 29, 2023 13:56
@Flater: Sure. Though I'll say for comment 5, in my experience of having been "absent of" experience, I found the extreme stricture on guidelines to lead me very often to seemingly-insuperable contradictions resulting in never producing a finished product at all.
The_Sympathizer
Jun 29, 2023 13:56
(Which produces no code [that gets used], and no code is worse than bad code [often]. The "proper" attitude, then, to guidelines, in my experience both with traps of extensive rewrite hells and literalism, should be - follow them until you see a contradiction. When contradiction appears, sacrifice one for a "more important" others to restore logical consistency and thus possibility to implement. Learn by experience whether the resulting design is good. Refactor/improve if it is not. In any case, make sure you are moving forward with the code. Iterate, rise, repeat, and iterate some more.)
The_Sympathizer
Jun 29, 2023 13:56
@Flater: (to clarify on my original question, what I mean by "guideline isn't to be taken absolutely tightly" vs. "stick to the guideline" - the point I'm trying to make there is that it is unreasonable to expect code will ever be "perfectly designed" out of the box, esp. when guidelines tart to contradict each other; there, you have to make a choice, and then see by retrospect and consequence [trial and error] what the "correct" design is. So rewriting/refactoring code is normal and essential part of programming. The trick is how you can avoid getting into "rewrite/refactor hell".)
The_Sympathizer
Jun 29, 2023 13:56
That said, I would agree the inversion of control method helps something else - it makes the method more extensible without modifying it, i.e. the "open/closed principle" for the method - which you may or may not need, but given the fact there are almost surely many more such filters out there, one likely will need to extend this. Now, if this is the answer to the second "why", then it should be made more overt/explicit in the answer post, I think. I.e. say, "this [labeling/etc.] solves the readability problem - BUT there is a second design problem here, which is extensibility ...".
The_Sympathizer
Jun 29, 2023 13:56
If the main concern is the readability, then a struct with labels makes the parameters legible. Since the concern is addressed, why are we continuing to question the design? If the design now must continue to be questioned, we must then have something else, beyond just the readability, that is motivating that ongoing questioning - and/or the readability is still not as good as it could be.
The_Sympathizer
Jun 29, 2023 13:56
@Flater : But we can and should again ask the "why" (perhaps 4 more times!). Why would, say, simply going and passing a single extra parameter with labels be still an unadvisable design, in the same spirit as to asking why the original one was? Moreover, as you point out, the guideline isn't to be taken absolutely tightly, so how or what can you absolutely call "sticking to the clean coding guidelines" vs. "not"?
 

 Discussion on answer by Flater: Can a…

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The_Sympathizer
Jun 20, 2023 13:04
@Flater : I just came up with an explicit example and now edited it right into the original post.
The_Sympathizer
Jun 20, 2023 13:04
@Flater: Yes, you're right, and I don't have that example on hand at this very moment, but I've encountered such a situation before. Thus, I can't discuss further at this time.
The_Sympathizer
Jun 20, 2023 13:04
@Flater: So then, as described ,this would not preclude, say, going back at a later time to add additional state getting methods in the event the persistence is required, right? That is, "not knowledge of persistence" simply means you don't need to know about persistence to write a functioning MyObject.
The_Sympathizer
Jun 20, 2023 13:04
@Flater: Ah I also see you posted two comments in succession. What then does "know about persistence" actually mean in this context? If what I describe (adding a method to reveal more state because persistence is possible ) is not "knowing about persistence" then I don't need to argue further because I misunderstood what was being advocated for and would much rather use the proper understanding so long as I can be confident it is the proper understanding.
The_Sympathizer
Jun 20, 2023 13:04
@Flater : One possibility - you have a configurable factory object where the configuration settings are passed in via constructor and then its only other method is one (say "produce()") to churn out many copies of some other objects. If you want to save the state on this object, you will need to explicitly add another method to dig that out or else somehow try to reconstruct/guess at it from the returned objects, which may or may not be possible - or maybe it is possible, but the "produce()" is very compute intensive or else not something you just wanna do "for fluff".
The_Sympathizer
Jun 20, 2023 13:04
But the point is you keep this to the minimum, and in particular you do not include any details of how the persistence operates or that persistence will be done. But you still do have to "inform" that it can be done, and that's not (or shouldn't be) a "no no".
The_Sympathizer
Jun 20, 2023 13:04
@Flater: I think something in the vein of Steve's point could still be made that the way that this has been written and talked about, though, does not easily give a clue as to what leeway actually can or cannot be assumed. As it seems you've obviously pretty much said what I've thought - the domain layer does (likely) need to "know" about persistence in any case where you want both a) encapsulation and b) there is any state that cannot be both arbitrarily accessed and mutated from public methods (i.e. get/set method or via constructor).
The_Sympathizer
Jun 20, 2023 13:04
@Steve: You bet. Seems there's no "perfect" design; you either trade off whether encapsulation or "ignorance" is more important (or get lucky that the DO's natural design just happens to be fully persistible), and that would be the most honest/"correct" possible answer. The tradeoff really is there, and you then choose the balance that maximizes the design goals of the particular application in question.
The_Sympathizer
Jun 20, 2023 13:04
But, then, each domain object is being designed to produce/map into those DTOs, or so to say in less literal language, it "has knowledge" of the fact it can be turned into DTOs. And since those DTOs are a persistence concern, that means it "has knowledge" of persistence. Or else, there is a different interpretation of "has knowledge" intended here than this one, and if that is so, then what is that? What is the "correct" interpretation of "does not know at all about persistence" if it doesn't mean "domain is designed as though persistence did not exist"?
The_Sympathizer
Jun 20, 2023 13:04
So some kind of code has to be present to tell it to take all that "private" stuff and write it down in a fully recoverable form, somehow, somewhere. That means either you break the encapsulation using reflection (etc.), or else you design explicitly into the domain layer code to feed the persistence layer "bits and pieces" of objects, e.g. DTOs or something that are pure data with no methods, in some encapsulation-preserving way.
The_Sympathizer
Jun 20, 2023 13:04
@Flater - Your "I disagree. The persistence layer should only be interested in persisting that which you give it." seems to miss the point of what I'm saying. It is logically impossible for the persistence layer to persist something without accessing the bits (as in 1/0 of data) that make it up. So whatever you give it, it better have all the relevant bits totally laid bare and public. Computer objects are made of data; you have to tell the computer to take that data and write it down on the hard drive (or whatever).
The_Sympathizer
Jun 20, 2023 13:04
@Steve : Yes, that's my point. If you are building interfaces into the domain to control what gets persisted, you are explicitly involving persistence in the domain design. The question is basically "how strictly do you take 'ignorant' (i.e. 'absent')" in the statement of this design pattern?
 

 Discussion on answer by J. Murray: Wh…

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The_Sympathizer
Oct 27, 2022 15:22
Worth pointing out that there is the Wigner formulation which lets you put quantum mechanics toe-to-toe with the classical mechanics you describe. Basically, $W$ is just like $\rho$, but it cannot be measured to arbitrary resolution or else it gives negative probabilities, and the Poisson bracket $\{\cdot,\cdot\}$ becomes "deformed" into the Moyal bracket $\{\{\cdot, \cdot\}\}_\hbar$ by the deformation parameter $\hbar$.
 

 Discussion on answer by ACuriousMind:…

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The_Sympathizer
Oct 23, 2022 01:06
@hft: The big problem with RQFT specifically, though, is it doesn't appear to have such a thing as a position operator. (Non-relativistic multiparticle QM-as-QFT does not suffer from this problem, so the problem really is relativity, not the "field" concept; QM, by itself, thus effectively provides a duality between fields and particles).
The_Sympathizer
Oct 23, 2022 01:06
Then QFT, or the second quantization, simply layers on top of this a mechanism for dynamically creating and destroying objects, which again does not change any of that preceding discussion (if anything, relativity is the one that really problematizes things more because it dinks in a lot of fraught ways with the idea of ascribing a "position" to a field quantum that is not present in non-relativistic QM-as-QFT).
The_Sympathizer
Oct 23, 2022 01:06
Of course, we certainly can make a mathematical description of a moving shape, it just isn't usually "covered". And this leads to an important but missable point about quantum mechanics: when we talk of the wave function, $\psi$, of a particle in even the first quantization, it actually doesn't stand in the theory at the place where the "shape" would be if we included it, it stands in the theory at the place where the kinematic attributes would be, namely position (and momentum).
The_Sympathizer
Oct 23, 2022 01:06
For what it's worth, the shape of an object does not appear explicitly in at least classical presentations of kinematics of a rigid body either, and only appears when interactions (collisions) are to be considered. The motion of a free object is basically the motion of its center of mass. So in this regard, saying it is "only" relevant for scattering isn't really as much of a "diminuition" as one might think it is.
 

 Discussion on question by Richard C: …

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The_Sympathizer
Oct 9, 2022 23:41
@niels nielsen: I don't have access to any of the links beyond what I've said, so that doesn't help. Can you explain though how a chemical explosive can generate conditions like that under this configuration (millions of times the detonation pressure, thousands of times the temperature)? Otherwise, it seems to me like there's a systematic confusion here similar to saying that because paper ignites at about 233 degrees C, then the flame is only 233 degrees C hot, or conversely that because a flame is much hotter, then you need that much to ignite paper.
The_Sympathizer
Oct 9, 2022 23:41
@Jon Custer : Yes, of course. That's the point. We're thus talking about igniting what would, in that configuration, constitute a "primary" here. And you're saying to do even that would require Sun-like conditions.
The_Sympathizer
Oct 9, 2022 23:41
@Jon Custer: Tell me how that a chemical explosive manages to equal the conditions inside the Sun, then, since that's how you ignite plutonium in a real fission (not fusion) bomb. If we could do that, seems fusion would be a lot easier than it actually is. Detonation pressure of chemical explosive is maybe around ~10 kbar from a quick google search (I looked up RDX, can't imagine there's something many OoM higher that's still chemical), which is just 1 GPa. If that is enough to do it, then definitely it seems deep Earth pressures should be far more than enough.
The_Sympathizer
Oct 9, 2022 23:41
(Note though this pressure can, in effect, be converted to implosive pressure with a suitable bomb design - that's how a fission-ignited fusion bomb, better known as the "hydrogen bomb", works. But we're just talking here about making a sphere of plutonium go boom by dropping it into the abyss.)
The_Sympathizer
Oct 9, 2022 23:41
@Jon Custer : This is the only article that comes up with a graph showing "pressure" - link.springer.com/chapter/10.1007/978-3-030-61373-0_2 - though the picture appears only in the Google result, else you need a pass. That plot does indeed show a peak around ~$10^{16}$ Pa, which is "like the center of the Sun" alright, but that is also at the maximum of fission, which means the pressure is being generated by fission, i.e. it is explosive, not implosive, pressure. I.e. the core is already very much lit at that point. OP is asking about lighting the core.
The_Sympathizer
Oct 9, 2022 23:41
@Jon Custer: Then it would be impossible to ignite a nuclear fission weapon with ordinary chemical explosives at all. We're talking fission, not fusion, here, remember.
The_Sympathizer
Oct 9, 2022 23:41
@niels nielsen: I'd tend to agree for the ocean, but the Earth's core? It is several times larger than the the Young's modulus of plutonium (Earth core ~ 360 GPa, Pu Young's modulus ~ 96 GPa). I imagine there would thus be significant compression of that plutonium core - and given it's symmetrical static pressure, that just might do the trick, no? Though the heat at depth may pose problems in that it might melt that core before it got deep enough if the melting point doesn't rise fast enough with compression, which would then disperse it by mixing with mantle and/or outer core material.
 

 Discussion on question by The_Sympath…

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The_Sympathizer
Jul 16, 2022 23:39
@Andrew: Yes. But if we are measuring to some finite mutual precision which we represent as an extended phase space region $R$, then can we create a distribution function so that the probability to obtain that $(x, p) \in R$ is given by $\iint_{(x, p) \in R} f_{xp}(x, p)\ d\mu$ where $\mu$ is phase space area/volume measure? Obviously this probability will be meaningless if $R$ is too small, but if $R$ is large enough (e.g. $\mu(R) > \hbar$, or even just in a limiting sense i.e. as $\mu(R) \rightarrow \infty$), it should be meaningful.
The_Sympathizer
Jul 16, 2022 23:39
@Andrew: For example, do we have some limiting effect such that, if $\hat{X}$ and $\hat{P}$ are two pseudo-position and pseudo-momentum operators in the sense of the referenced thread, that the probability assigned to the proposition $(X, P) \in R$, when $R$ is suitably large (i.e. measure much greater than $\hbar$), is at least "mostly" (i.e. bounded to a small subinterval of $[0, 1]$ for a given fixed quantum state) independent of the choice of the two operators?
The_Sympathizer
Jul 16, 2022 23:39
@Andrew: If the two are simultaneously measurable for a region with size much larger than $\hbar$, then what joint PDF is being measured or, at least, what probability measure on regions $R$ of phase space? How does this thing start to fail when the size of $R$ shrinks to approach 1 $\hbar$?
The_Sympathizer
Jul 16, 2022 23:39
@Andrew: So then, "what is happening" when you "look with your eyes" that allows for some combination of the two that does not involve order?
The_Sympathizer
Jul 16, 2022 23:39
@Andrew: As the thread is saying (or at least @pglpm), though, you can make such measurements, but the implication seems to be they are not repeatable (beyond the limits set out by the Heisenberg principle). I.e. there is no way to prepare a system that reliably give you the same $(x, p)$ every time. But that's just what you'd also get from a pdf with nontrivial spread that can never be made trivial, no?
The_Sympathizer
Jul 16, 2022 23:39
@Andrew : I know about the Wigner distribution function (though it seems like a hack, and the formalism becomes way more difficult to tract than the neat linear-algebra formalism of Hilbert QM). But why can't a true PDF $f_{xp}$ be defined? Just because there is a limit to the simultaneous "resolution" you can have for both doesn't mean you can't have a pdf: it could just be you'll never reduce that pdf to a delta spike, meaning serial measurements would not be repeatable beyond a point, which I believe is what was also mentioned somewhere in the given thread or a link from it.
 

 Discussion on answer by Ruy: Basis-fr…

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The_Sympathizer
Jun 24, 2022 02:52
@WillG : agreed, this is awesome!
 

 Discussion on answer by Paul Ross: Na…

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The_Sympathizer
May 28, 2022 23:55
@Logikal: The problem missed is that even if the claim is true, the argument being used to support it is still a fallacy - i.e. it provides us with no knowledge of any such supposed truth. A claim can be true and yet reasoning used in support of that claim still be fallacious. Simple example: "Believe me that 2+2=4 or else!" This is an appeal to threat, which is a fallacy, but the claim, 2+2=4, is still true.
 

 Discussion on answer by Mark Saving: …

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The_Sympathizer
Sep 1, 2021 08:40
@Mark Saving: So what happens when we consider simple "three valued logics" like mentioned here?: en.wikipedia.org/wiki/Three-valued_logic#Logics One might at first think these work okay because they do not validate the principle of contradiction - for example in the simple Kleene logic $\neg (A \wedge \neg A)$ can be "unknown" (U), not necessarily "true" (T). But on the other hand, it seems $\neg A \wedge \neg \neg A$ is never true - it is at most "unknown" (U). So does this mean the "U" value here is not a "real" truth value and so in a sense it fails to achieve its mission?
The_Sympathizer
Sep 1, 2021 08:40
@Mark Saving: What then, would a logic need to internally have a "third truth value"?
 

 Discussion on answer by Stilez: Does …

Imported from a comment discussion on skeptics.stackexchange.c...
The_Sympathizer
Aug 11, 2021 15:48
@Stilez : Yes, but if evaluation of what is and isn't "good" vs. "junk" science requires this much in-depth knowledge - and it only makes sense it should, after all, that's why people get Ph.D.s - then it seems it is pretty much impossible to do that for every field that one may encounter claims in. We can't have a Ph.D. (or similar) in everything, and if we could reliably evaluate the quality of research without (the level of knowledge conferred by) one, there'd be no need for peer review.
The_Sympathizer
Aug 11, 2021 15:48
@J.Hrisch : Which makes one wonder then, how can the "majority of people" avoid being duped by these kinds of arguments?
 

 Discussion on answer by Pieter Geerke…

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The_Sympathizer
Aug 4, 2021 13:52
I also think to conceive of the missing part here as "where does the ounce come from, then?" is not right - what's missing is "where does 5760 or 7000 grains come from?"
The_Sympathizer
Aug 4, 2021 13:52
@Pieter Geerkens : Yes, but 5760 evenly divides by 12 into 480, i.e. a whole number of grains to the ounce, so my guess is that it provides a divisible number that approximates the weight of some object, such as perhaps, a loaf of bread as suggested. The question is, what exactly was that object, or is that unavailable from existing historical evidence?
The_Sympathizer
Aug 4, 2021 13:52
(Of course, it could also be that there is no specific object - that the number was chosen because it divides into 12s and also happens to be "just the right" magnitude for many small but substantial objects of the time.)
 

 Discussion on answer by Nihar Karve: …

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The_Sympathizer
May 17, 2021 13:47
So then would a reasonable way to put it be this?: The "unified quantum field" (to the extent of electroweak theory at least) has two phases, like water has a fluid phase and solid phase, and when you heat it up to the phase change temperature, or cool it below, it shifts. In the hot phase, it can manifest 5 massless particles, while in the cold phase, it manifests 4 massive (including the Higgs) and 1 massless particle (the photon). The cold phase particles don't have mass because the Higgs particle is in this bunch, they have mass because that's a property of that phase, just as rigidity is
The_Sympathizer
May 17, 2021 13:47
a property of the solid phase of water, but not of the fluid phase.