Muireall

Karma: 219

Muireall 18 Sep 2023 2:39 UTC
6 points
2
on: Memory bandwidth constraints imply economies of scale in AI inference
Whether this imbalance can possibly be cheaply engineered away or not might determine the extent to which the market for AI deployment (which may or may not become vertically disintegrated from AI R&D and training) is dominated by a few small actors, and seems like an important question about hardware R&D. I don’t have the expertise to judge to what extent engineering away these memory bottlenecks is feasible and would be interested to hear from people who do have expertise in this domain.
You may know this, but “in-memory computing” is the major search term here. (Or compute-in-memory, or compute-near-memory in the nearterm, or neuromorphic computing for an umbrella over that and other ideas.) Progress is being made, though not cheaply, and my read is that we won’t have a consensus technology for another decade or so. Whatever that ends up being, scaling it up could easily take another decade.

Muireall 18 Sep 2023 1:59 UTC
5 points
0
on: Muireall’s Shortform
Since Raemon’s Thinking Physics exercise I’ve been toying with writing physics puzzles along those lines. (For fun, not because I’m aiming to write better exercise candidates.) If you assume an undergrad-level background and expand to modern physics and engineering there are interesting places you can go. I think a lot about noise and measurement, so that’s where my mind has been. Maybe some baseline questions could look like the below? Curious to hear anyone’s thoughts.
Pushing a thermal oscillator
You’re standing at one end of a grocery aisle. In your cart, you have a damped oscillator in a thermal bath, initially in equilibrium.
You push the cart, making sure it moves smoothly according to a prescribed velocity profile, and you bring it to a stop at the other end of the aisle. You then wait for the oscillator to reach equilibrium with its bath again.
The final temperature is
1. Cooler than before
2. Exactly the same
3. Hotter than before
4. Not enough information. More than one of the above may be true because of one or more of the following:
  1. You can only answer in expectation.
  2. It depends on the properties of the oscillator.
  3. It depends on the cart’s trajectory.
Thermal velocity and camera speed
You’re observing a particle undergo thermal motion in a fluid. It’s continuously bombarded by fluid molecules that effectively subject the particle to a white noise force and velocity damping. You estimate that it tends to lose its momentum and change direction on a timescale of 1 millisecond.
You want to get some statistics on the particle’s velocity. You know the average velocity is zero, but there will be some variance that depends on temperature. You recall that in equilibrium that the particle should have velocity $v$ with probability proportional to the Boltzmann factor $e^{- m | v |^{2} / 2 k_{B} T}$ , giving a root mean square thermal velocity $v_{t h}$ .
You calculate velocity by taking pairs of pictures at different times, then dividing the change in position by the time step. Your camera has an effectively instantaneous shutter speed.
In experiment 1, you use a time step of 0.1 milliseconds to measure velocity. In experiment 2, you use a time step of 10 milliseconds.
You collect distributions of measured velocities for each experiment, giving root mean square velocities $v_{1}$ and $v_{2}$ , respectively. What do you find?
1. $v_{1} = v_{2} = v_{t h}$
2. $v_{1} < v_{2} < v_{t h}$
3. $v_{2} < v_{1} < v_{t h}$
4. $v_{2} < v_{t h} < v_{1}$
5. $v_{t h} < v_{2} < v_{1}$

Muireall’s Shortform

Muireall18 Sep 2023 1:59 UTC

3 points

1 comment1 min readLW link

Muireall 8 Sep 2023 12:29 UTC
9 points
2
in reply to: dr_s’s comment on: Measure of complexity allowed by the laws of the universe and relative theory?
Stochastic thermodynamics may be the general and powerful framework you’re looking for regarding molecular machines.

Muireall 9 Aug 2023 1:13 UTC
1 point
0
in reply to: Raemon’s comment on: Exercise: Solve “Thinking Physics”
I enjoyed it, although I’m already the sort of person who thinks Thinking Physics is fun—both the problem solving and the nitpicking about what constitutes a correct explanation. It seems worth doing at least a handful of problems this way, and more broadly deliberately practicing problem solving and metacognition about problem solving. Thinking Physics could be a good complement to Problem Solving Through Problems or How To Solve It, since in my (limited) experience you get quickly diminishing returns to anything but competition math with collections like that.

Muireall 9 Aug 2023 0:13 UTC
11 points
0
on: Exercise: Solve “Thinking Physics”
OK, a shot at Challenge I, with Poof and Foop, Steam Locomotive, and Expansion of Nothing. Felt like all three are in the sweet spot. I personally dislike Expansion of Nothing.
Poof and Foop:
The problem statement is a bit leading: there’s some kind of inversion symmetry relationship between the two cases, so it should go the opposite direction, right?
Initially, definitely. The puncture means that there’s less pressure on the right side—instead of colliding with the can, some particles go inside.
But those particles end up colliding with the interior left side anyway. So it seems like it should even out, and at the end the can won’t be moving.
So my guess is (c). Can I make myself more confident?
Why doesn’t an inversion argument go through? Well, the compressed air can is drawn in vacuum, but the vacuum can doesn’t empty the environment.
So it’s not simply time reversal. If the compressed air can were in air, then we might have some kind of symmetry between air particle and absence of air particle,
but then the compressed air can would slow down due to drag and stop in the limit. So that still points to (c). That also works as a thermodynamic argument—the first can isn’t equilibrating with anything, so none of the work goes to heat. 95% confidence feels good.
*checks* OK, looks like I was thinking about it right, and my explanation for why the naive inversion is wrong is equivalent to sketch II.
Reflection: The main interesting thing here is the fake symmetry argument. My favorite problems have tempting solutions that don’t work for subtle reasons. I think it’s important not to count problems solved until you can pinpoint why those solutions fail.
What did I use here? If you’re dealing with pressure, you can probably get an answer with forces or with thermodynamics. A net force can be thought of as a single force or as lack of a balancing force. That’s the symmetry idea.
I’m not very good at babbling. I’m basically looking over what I wrote and renarrating it. Words to words.
Steam Locomotive:
We might want to think about torque and the height of the axle.
Or maybe it’s about wheel radius. One cycle takes you further with bigger wheels.
I think these both point to (b).
I’m a little confused because thinking about the wheel heights of sports cars and trucks would push me towards (a). But cars have gears. Directly driving small wheels is basically low gear.
Not sure how I’d know if the answer were (c) or (d). Seems like you’d need background knowledge not in the question.
I should think about actual forces to get to 95% confidence.
Let’s say the engine puts out the same force in both cases. Then, in II, each wheel sees half as much force from the engine,
but the ground exerts force on twice as many wheels, so that part’s a wash. But because the wheels are smaller, the ground
needs to exert more force per unit engine force to keep the wheel from slipping (same torque).
So for the same engine, II seems to give more accelerating force, while I gives higher top speed. I’d put 95% on (b).
*checks* OK, seems like I had the right thought. Could I have been as confident from the distance-per-cycle argument alone? Rather than look at forces,
the author’s answer argues that we know the locomotive that goes a shorter distance in the same number of engine cycles must
be putting more energy into each mile it travels. I considered that, but I wasn’t sure it was a valid step.
Why couldn’t you just be getting less work from the engine? Well, it’s the same piston with the same motion.
My force calculation already needs that assumption, it just makes the final connection with the acceleration.
Reflection: I feel like I don’t know much about automotives. (Is a locomotive an automotive, by the way? I think so, it’s just locomotives involve a track.) I can describe transmission and gears and engines and so on if I think about it, but I don’t have much intuition. Like, I can’t explain why it’s one way and not another, or how different cars solve different problems.
I just feel like I should have been able to answer the question immediately. If I could drive stick, would that help? Probably not. I already ride a bike and didn’t immediately see the analogy.
What did I use? Qualitative personal experience. I picked a misleading experience but reasonably didn’t weight it above thinking through the problem. Identifying relevant considerations. Didn’t stop at the first idea.
Expansion of Nothing:
Oh, this one’s nasty. It has to expand, right?
If you took an iron disk and drew a circle where the hole is, the circle would expand.
If you cut that disk out and heat up the cutout, the disk expands the same amount.
So everything outside the circle can’t be exerting any net force at the boundary, and the hole has to stay the same size as the disk.
I don’t see any problems with this argument, but can I explain why other arguments don’t work? Why can’t thermal expansion generate stress instead of allowing uniform expansion? I guess in a sense I just gave the reason, but why does the gap shrink if you cut a gap in a rod instead? Well, when you have only one piece, it’s like applying a magnification transformation, which requires an origin. But the origin is arbitrary—you can just recenter. With two separate pieces, the two origins of magnification are no longer arbitrary.
*checks* Yeah, the author’s answer doesn’t go there, unfortunately.
Reflection: This problem feels really annoying to me. Maybe I saw it a long time ago and got it wrong? Or maybe it’s that you never have anything that’s free to expand uniformly. It’s braced against something, or it’s sitting on something with a different coefficient of thermal expansion, and you do get stress and it does matter how the thing is patterned.
This feels like a problem where you’re supposed to think about limiting cases. Like, if you have an atomic ring, obviously it expands. I don’t know if you can justify jumping to the right answer from that, though. If the disk is thick and the cutout doesn’t go all the way through, it expands. Ehh. You still need an argument that it expands the same.

Muireall 8 Aug 2023 23:07 UTC
1 point
0
in reply to: Raemon’s comment on: Exercise: Solve “Thinking Physics”
For context if anyone needs it, the Physics GRE is (was?) a multiple-choice exam where you get penalized for wrong answers but not for blanks. It works out so that if you eliminate one answer there’s no harm in guessing, in expectation. There’s also considerable time pressure—something like 90 seconds per question on average.
how much deliberate effort you put into calibrating yourself on “how much effort to put into multiple choice questions”
Enough to get through all questions with some time left over, even if that meant guessing on some I could fully solve. I’d mark the questions I’d guessed on with different symbols that let me go back at the end and prioritize solving them. For three or so practice tests, I systematically went over every problem that I missed, guessed, or spent a long time on and did the metacognitive thing including questions like “how long did I think this would take? when was I 50% confident? when should I have decided to move on? how could I have decided faster?” (Using purely retrospective judgment—I wasn’t actually timing individual questions or anything more complicated.)
whether you put any deliberate effort into transferring that into the PhD experience
Not really. I think I had some notion that being able to solve small problems quickly could lead to a sort of qualitatively better fluency, but in the end there just wasn’t enough in common between test content/conditions and research (or even coursework) to prioritize that. I definitely didn’t learn the lesson that I was generally underconfident.
what did you actually do in your PhD experience?
Pretty normal experimentalist route, maybe heavier on math and programming than typical. Coursework for 1-2 years shading into helping with senior students’ experiments, then designing and running my own.
what do you think would have better prepared you for PhD experience?
In the end I was reasonably well prepared in terms of technical knowledge, problem solving, [meta]cognitive skills, and so on (irrespective of the GRE). I think I mostly lacked perspective, particularly in terms of choosing problems and working with a supervisor. I’d guess, starting with most helpful, one or more of these:
1. Industry experience with a good manager
2. More research experience in other subjects
3. Research in the same subject
4. Other industry experience
As far as things I could have done instead with the time I used to study, I don’t know. Make friends with grad students?

Muireall 8 Aug 2023 21:16 UTC
1 point
0
on: Exercise: Solve “Thinking Physics”
I only ever flipped through Thinking Physics for fun, but what I remember is that I tended to miss easier problems more often. If I spent time thinking about one, really making sure I got it right, I’d probably get it. Outside those, there were some that really were elementary, but I’d often find myself thinking I’d looked at the author’s answer too soon—a self-serving “well, I would have gotten this, if I were really trying.” I might say the problem was that I couldn’t tell when I needed to really try.
This does remind me a bit of how I studied for the physics GRE (do people still take that?), particularly getting calibrated on multiple-choice confidence and on how long to spend on problems. Unfortunately, but perhaps not surprisingly, very little of that study transferred to my PhD experience.

Muireall 2 Aug 2023 12:56 UTC
3 points
1
in reply to: Liam Donovan’s comment on: My current LK99 questions
From the six-author paper: “In the first region below red-arrow C (near 60 °C),
equivalent to region F in the inset of Fig. 5, the resistivity with noise signals can be regarded as
zero.” But by “noise signals” they don’t mean measurement noise (and their region C doesn’t look measurement-noise limited, unless their measurement apparatus is orders of magnitude less sensitive than it should be) but rather sample physics—later in that paragraph: “The presence of noise in the zero-resistivity region is often attributed to phonon vibrations at higher temperature.”
The other papers do seem to make that claim, but for example the April paper shows the same data but offset 0.02 Ohm-cm on the y-axis (that is, the April version of the plot [Fig. 6a] goes to zero just below “Tc”, but the six-author arXiv version [Fig. 5] doesn’t). So whatever’s going on there, it doesn’t look like they hooked up their probes and saw only the noise floor of their instrument.

Muireall 2 Aug 2023 3:44 UTC
37 points
2
on: My current LK99 questions
I did a condensed matter experiment PhD, but high Tc is not my field and I haven’t spent much time thinking about this. [Edit: I didn’t see Charlie Steiner’s comment until I had written most of this comment and started editing for clarity. I think you can treat this as mostly independent.] Still, some thoughts on Q1, maybe starting with some useful references:
Bednorz and Müller, “Possible High Tc Superconductivity in the Ba—La—Cu—O System” (1986) was the inciting paper for the subsequent discoveries of high-Tc superconductors, notably the roughly simultaneous Wu, Ashburn, Torng, et al. (1987) and Cava et al. (1987) establishing superconductivity in YBCO with Tc > 90K. The first paper is more cautious in its claims on clearer evidence than the present papers. The latter two show dispositive measurements.
I might also recommend Ekin’s Experimental Techniques for Low-Temperature Measurements for background on how superconductors are usually measured (regardless of temperature). It discusses contacts, sample holders, instrumentation, procedures, and analysis for electrical transport measurements in superconductors, with a focus on critical current measurements. (I don’t think skimming it to find a graph or statement that you can apply to the present case will be very helpful, though.)
One person alleges an online rumor that poorly connected electrical leads can produce the same graph. Is that a conventional view?
It’s well understood that a jump in the I-V curve does not imply superconductivity. Joule heating at high currents and thermal expansion, for example, can cause abrupt changes in contact resistance. I’m not sure exactly what it would take to reproduce that graph, but contact physics is gnarly enough that there’s probably a way, together with other experimental complications.
If this material is a superconductor, have we seen what we expected to see? Is the diminishing current capacity with increased temperature usual?
In the roughest sense, yes. The critical current density for a superconductor decreases as temperature increases and as magnetic field increases. Quantitatively, maybe. There are evidently other things going on, at least. (In another sense, the papers aren’t really what I’d expect a lab that thought they had a new superconductor to present. But I think that can be explained between reproducibility issues, the interpersonal issues rushing publication, and the fact that they’re somewhat outside the community that usually thinks about superconducting physics.)
How does this alleged direct measurement of superconductivity square up with the current-story-as-I-understood-it that the material is only being very poorly synthesized, probably only in granules or gaps, and hence only detectable by looking for magnetic resistance / pinning?
In an impure sample you would see high residual resistance below Tc (I think the authors do, but I’m not confident at a glance particularly given paper quality problems) and broad transitions due to a spread of transition temperatures over superconducting domains (it seems to me that the authors see very sharp transitions, although data showing the width in temperature from the April paper is omitted from the arXiv papers). The worse these are, the more mundane explanations are viable (roughly speaking), which is part of why observing the Meissner effect is important. But this is a good question. To some extent people are “vibing” rather than getting a story straight.

Muireall 30 Jul 2023 0:20 UTC
5 points
3
on: If I showed the EQ-SQ theory’s findings to be due to measurement bias, would anyone change their minds about it?
I hope you don’t mind my piling on. This is one of those things (along with moral foundations theory) where it really frustrates me that people seem to believe it has much better scientific backing than it does.
My concern is that people didn’t start believing in the EQ-SQ theory based on statistical correlations found with Simon Baron-Cohen’s scales. They presumably started believing in it based on fuzzy intuitions arrived at through social experience.
It’s hard to gloss empathizing-systemizing/extreme male brain as a theory that Baron-Cohen himself arrived at in a principled or scientific way.
As presented in The Extreme Male Brain Theory of Autism (2002), researchers do find apparent sex differences in behavior and cognition. It’s possible to frame many of these as female-empathizing and male-systemizing. Then there are a bunch of other, mostly unrelated studies (and a few citation-free stereotypes) of behavior and cognition in autistic people, which can also be framed as low-empathizing and high-systemizing. The authors draw this figure, classifying brain types by the difference between empathizing and systemizing dimensions in “standard deviations from the mean”:
But the first, key quantitative paper I’m aware of is Empathizing and Systemizing in Males, Females, and Autism (2005). The actual plot of EQ and SQ looks like this:
The authors write, “In this particular case, it was possible to see immediately what combination of EQ and SQ govern the data, but in general this might require using a principal components analysis.” By this they mean the C and D axes (sum and difference of normalized EQ and SQ), writing, “The combination of the normalization steps and the rotation represents a principal components analysis of of this correlated bivariate data set.” This paper doesn’t quote standard deviations of EQ and SQ scores, but it’s “possible to see immediately” that (1) the male-female differences on both axes are much less than two standard deviations (as indicated by the earlier, schematic figure, which also appears in later publications), and (2) the male-female difference in EQ+SQ (C Axis) is insignificant, while the autistic group has much lower C-Axis scores. This should not have passed review.
Clearly, I’m not someone whose mind you’re trying to change, but I think your concern is on target. EQ-SQ is a bad measure, but even taken seriously it provides about as much evidence against the “extreme male brain” idea as it does in favor. I doubt that highlighting more problems with EQ-SQ is going to move people very much.

Muireall 12 Jul 2023 12:24 UTC
1 point
0
in reply to: tailcalled’s comment on: I think Michael Bailey’s dismissal of my autogynephilia questions for Scott Alexander and Aella makes very little sense
I’m speaking from memory of reporting here, but my understanding is that there was a specific turning point in 2019/2020 when one of these orgs focus tested a bunch of messages and found that trans youth issues worked well, particularly as a wedge. (That is, the opposition were split on it.) US Americans, when polled, have a bunch of weirdly self-contradictory answers to questions on trans issues but are generally more supportive than not, depending on how they’re asked. My guess is they mostly don’t think about it too much, since there are plausibly a million or two trans people in the US, many of whom pass or are closeted.
In the previous cycle, “bathroom bills” had failed and generated backlash. In the current cycle focused on trans youth, there’s more uncertainty among people who think of themselves as liberals, and for a variety of reasons large news media organizations like the NYT have been happy to play along with conservative agenda-setting. There’s some decentralized, populist opposition, but it’s largely activated by forces far out of proportion to the number of trans athletes or minors getting gender-affirming surgery.
No idea what Musk’s deal is. Unrelatedly, I’m also very skeptical that Libs of TikTok is primarily motivated by sincere concerns.
Edit: here’s a handful of sources just from looking around again.
NYT (2023): How A Campaign Against Transgender Rights Mobilized Conservatives (“it was also the result of careful planning by national conservative organizations to harness the emotion around gender politics”)
Axios (2023): The forces behind anti-trans bills across the U.S.
NBC News (2017), on ADF and bathroom bills: This Law Firm Is Linked to Anti-Transgender Bills Across the Country
The Guardian (2020), on other ADF activities and the new focus on student athletes: The multimillion-dollar Christian group attacking LGBTQ+ rights
Fairness and Accuracy In Reporting (2023): NYT’s Anti-Trans Bias, by the Numbers
I don’t endorse everything that’s written in these, but this is more or less the thing I’m talking about.

Muireall 11 Jul 2023 20:27 UTC
10 points
1
in reply to: tailcalled’s comment on: I think Michael Bailey’s dismissal of my autogynephilia questions for Scott Alexander and Aella makes very little sense
I don’t know if “decentralized” is quite right. For example, the Alliance Defending Freedom specifically has been an instrumental driving force behind legislative pushes in many states in the last few years. Legislation, election messaging, and media cycles more generally tend to be driven by a handful of conservative/evangelical nonprofits with long-established national operations, also including, for example, the Independent Women’s Forum and the Family Research Council. I would also characterize it as more of a wedge issue than a resonant one, although that’s more complicated.

Muireall 11 Jul 2023 16:32 UTC
6 points
9
in reply to: TracingWoodgrains’s comment on: Blanchard’s Dangerous Idea and the Plight of the Lucid Crossdreamer
Poorly constructed public narratives, though, make for bad policy and bad culture.
Do they, though? I’m honestly not too worried about this. That’s one reason I mentioned “born this way”. Of course, I think even just going by self reports “internal sense of gender” is a reasonable first approximation with wide coverage, I think the current policy and cultural agendas for trans rights are pretty much the right ones, and I think that’s true pretty much regardless of “underlying truth of the phenomenon”.
“My body, my choice” has already been thoroughly absorbed by the abortion debate, but a similar approach encapsulating the essence of morphological freedom is an easy case to make and a hard one to reject.
You’d think so! But people are really weird about sex, and I think it’s going to be a tough fight without addressing that head on. Also, related to Ben Smith’s comment, the political/medical aspects are generally more material.
Regarding
The idea of gender as an essence separate to sex, intrinsic to all, is a much steeper request, one that demands people realign their view of what is rather than what ought to be. If they cannot or will not realign that view, whatever their perspective on morphological freedom, they are placed in the role of Enemy Of The Cause.
and
to assert it becomes a threat and to examine its implications or propose it as a basis for policy is to all but declare war on the most vocal progressive trans activists.
This seems hyperbolic? Both in terms of the hostility and the “demand” to accept truth claims. I’m sure you can get that reaction from some people, but they don’t speak for everyone; and you only have to live in a society with the most combative activists, not make them think you’re a good person. Outside of prominent Twitter figures and what gets amplified in certain media circles, people tend to be willing enough to talk in good faith and accept you as an ally of convenience if you’re respectful. They’re just (understandably!) wary. (Edit: This is just my perspective. I don’t speak for anyone else—I just don’t see this kind of melodrama on everyday scales.)
a consistent approach as I wrestle with phenomena like trans-species identity that seem closely connected
I wouldn’t expect any underlying consistency here. Honestly, I think “underlying truth of [transgender identity]” already presupposes too much consistency and leads to bad predictions.

Muireall 9 Jul 2023 3:45 UTC
3 points
on: Taboo Truth
It’s often hard to get a good handle on a proposition if you don’t feel able to talk about it with people who disagree. I’ve offered in the past to privately go over any potentially dangerous ideas anyone thinks they’ve found.

Muireall 9 Jul 2023 3:20 UTC
4 points
1
in reply to: Raemon’s comment on: Blanchard’s Dangerous Idea and the Plight of the Lucid Crossdreamer
There aren’t really novel thoughts and arguments to preserve nuance from—most of what the summary misses is that this is a story of the author’s personal psychological journey through the bullet points. I understand why it’s been downvoted, but I’m glad someone was forthright about how tedious it is to read more tens of thousands of words of variations on this particular theme.

Muireall 9 Jul 2023 3:04 UTC
12 points
11
on: Blanchard’s Dangerous Idea and the Plight of the Lucid Crossdreamer
I’m not sure how much of the narration is about you in the present day, or exactly what you’re looking for from your audience, but there’s a bit I still want to respond to.
I’m a transhumanist. I believe in morphological freedom. If someone wants to change sex, that’s a valid desire that Society should try to accommodate as much as feasible given currently existing technology. In that sense, anyone can choose to become trans.
The problem is that the public narrative of trans rights doesn’t seem to be about making a principled case for morphological freedom, or engaging with the complicated policy question of what accommodations are feasible given the imperfections of currently existing technology. Instead, we’re told that everyone has an internal sense of their own gender, which for some people (who “are trans”) does not match their assigned sex at birth.
Okay, but what does that mean? Are the things about me that I’ve been attributing to autogynephilia actually an internal gender identity, or did I get it right the first time? How could I tell? No one seems interested in clarifying!
I have some sympathy here. It’s certainly frustrating when it seems no one has the patience to engage thoughtfully, even if no one is obliged to answer your questions. For things like this, it’s especially common to be tired of explaining or justifying oneself, or to be wary after getting drawn in by people asking similar things who turn out to lack genuine curiosity, or just to not want to speak for others.
Some trans people might be interested in making a principled case, but I think most just want to live the way they choose. That’s the outcome “the public narrative of trans rights” serves and (I think) ought to serve. I agree that morphological freedom is wonderful, but even if one thinks the public narrative makes bad philosophical commitments, I don’t see a way to get there from here that doesn’t go through pragmatic trans acceptance.
Some people feel they can choose whether to cultivate homosexual attraction or not. Some find that (real or illusory) choice liberating and meet new partners, while others find in it reasons to expect conversion therapy to work. “Born this way”, as a slogan, leaves some people out and raises objections from those who note that it shouldn’t matter whether it’s nature, nurture, or choice. But within my lifetime it seems to have become common knowledge that trying to force someone to change their orientation is ineffective and harmful.
Similarly for “man born in a woman’s body”, a distinction between sex and gender, or “anyone who wants can be trans”. Some trans people embrace one narrative or another with the relief of finally finding a description of their experiences. Many find ways to understand themselves in more nuanced terms, some philosophical, some psychological. These may try to steer the narrative, or they may publicly amplify the simplest available explanation that lets them get by rather than add nuance that they expect will be rounded off, misunderstood, or used against them. Some don’t really worry about it one way or another. Many do all of these at different points in their lives.
It seems part of your frustration comes from wanting the public discourse to do more than serve a purpose, perhaps to be more internally consistent or more uniformly settled. I don’t see you finding satisfaction here, and even less likely on your terms. Also, frankly, it sounds like your friends who egged you on, particularly in grandiose language, were not acting in your interests. I hope you have more stabilizing people in your life these days.
I also imagine it’s difficult to have your understanding of yourself rejected as a misinterpretation of your experiences or as politically inconvenient, and meanwhile to see people around you as so much like you while they deny fellowship, as it were. I’m sure you’ve heard this before, but I suspect your picture of others’ internal processes is misleading you. I don’t think you’ve stumbled on a taboo truth so much as on one of those nuances that get misunderstood or rounded off too easily to serve their purpose. As far as there’s a need to talk about it, it seems reasonable to be particularist and not immediately bring in the baggage that “autogynephilia” carries.

Muireall 23 Jun 2023 21:25 UTC
13 points
5
in reply to: jacob_cannell’s comment on: My side of an argument with Jacob Cannell about chip interconnect losses
Thanks for replying. This is a lot clearer to me than prior threads, although it also seems as though you’re walking back some of your stronger statements.
I think this is still not quite a correct picture. I agree with this:
For electronic devices at maximum packing density where you naturally represent bits with single electrons, and the de broglie wavelength is then quite relevant as a constraint on maximum packing density due to quantum tunneling etc.
However, at maximum packing density with single-electron switches, the energy requirements per area of interconnect space are still not related to dissipation, nor to irreversible-bit-erasure costs from sending signals tile by tile. Rather, the Cavin/Zhirnov argument is that the extra energy per area of interconnect should be viewed as necessary to overcome charge shot noise in the bit-copy operations required by fan-out after each switch. Abstractly, you need to pay the Landauer energy per copy operation, and you happen to use a couple interconnect tiles for every new input you’re copying the switch output to. Physically, longer interconnect reduces signal-to-noise ratio per electron because a single electron’s wavefunction is spread across the interconnect, and so is less likely to be counted at any one tile in the interconnect.
Thinking of this as accumulating noise on the Landauer scale at each nanoscale transmission step will give incorrect results in other contexts. For example, this isn’t a cost per length for end-to-end communication via something other than spreading an electron across the entire interconnect. If you have a long interconnect or coaxial cable, you’ll signal using voltage transmitted at the speed of light over conduction electrons, and then you can just think in terms of resistance and capacitance per unit length and so on. And because you need 1V at the output, present devices signal using 1V even though 1mV would overcome voltage noise in the wire. This is the kind of interconnect people are mostly talking about when they talk about reducing interconnect power consumption.

Muireall 22 Jun 2023 21:40 UTC
22 points
2
in reply to: Muireall’s comment on: My side of an argument with Jacob Cannell about chip interconnect losses
The “tile”/cellular-automaton model comes from Cavin et al., “Science and Engineering Beyond Moore’s Law” (2012) and its references, particularly those by Cavin and Zhirnov, including Shankar et al. (2009) for a “detailed treatment”. As @spxtr says in a comment somewhere in the long thread, these papers are fine, but don’t mean what Jacob Cannell takes them to mean.
That detailed treatment does not describe energy demands of interconnects (the authors assume “no interconnections between devices” and say they plan to extend the model to include interconnect in the future). They propose the tiling framework for an end-of-scaling processor, in which the individual binary switches are as small and as densely packed as possible, such that both the switches and interconnects are tile-scale.
The argument they make in other references is that at this limit, the energy per tile is approximately the same for device and interconnect tiles. This is a simplifying assumption based on a separate calculation, which is based on the idea that the output of each switch fans out: the output bit needs to be copied to each of around 4 new inputs, requiring a minimum length of interconnect. They calculate how many electrons you need along the length of the fan-out interconnect to get >50% probability of finding an electron at each input. Then they calculate how much energy that requires, finding that it’s around the minimal switching energy times the number of interconnect tiles (e.g. Table 28.2 here).
For long/”communication” interconnects, they use the same “easy way” interconnect formula that Steven Byrnes uses above (next page after that table).
The confusion seems to be that Jacob Cannell interprets the energy per tile as a model of signal propagation, when it is a simplifying approximation that reproduces the results of a calculation in a model of signal fan-out in a maximally dense device.

Muireall 22 Jun 2023 14:03 UTC
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in reply to: Steven Byrnes’s comment on: My side of an argument with Jacob Cannell about chip interconnect losses
Oh, no. I just meant to highlight that it was a physically incorrect picture. Metallic conduction doesn’t remotely resemble the “electronic cellular automata” picture, any version of which would get the right answer only accidentally, I agree. A calculation based on information theory would only care about the length scale of signal attenuation.

Even for the purposes of the cellular model, the mean free path is about as unrelated to the positional extent of an electron wavefunction as is the de Broglie wavelength.

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