David Udell

• David Udell 15 Jun 2026 10:15 UTC

  4 points

  0

  in reply to: Snehasis Mukhopadhyay’s comment on: An­nounce­ment: Iliad In­ten­sive + Iliad Fellowship

  For the Iliad Fellowship, the more selective program,

  Competitive candidates are PhD or postdoctoral (or equally experienced) researchers in math, physics, or a related field.

  ...

  The Fellowship is most centrally aimed at PhD and postdoctoral researchers. However, we encourage interested individuals with substantial prior research experience in their field of expertise to apply, regardless of credentials. The first stage of the application is designed to be easy to complete.

  So it’s explicit that, while we’re after the sort of people who would have or be doing a math/​theoretical physics/​theoretical CS doctorate, we don’t require the degree.

• David Udell 9 Jun 2026 11:54 UTC

  3 points

  0

  in reply to: Eddie Jean’s comment on: An­nounc­ing: Iliad’s Fall 2026 Programs

  Anywhere on Earth (AoE) is a calendar designation that indicates that a period expires when the date passes everywhere on Earth. It is a practice to help specify deadlines such as “June 9, 2026, End of Day, Anywhere on Earth (AoE)” without requiring time zone calculations or daylight saving time adjustments.

  Maybe “EoD” is then redundant. To my eyes, though, it disambiguates “AoE,” as in the Wikipedia quotes. When I google “AoE” by itself, I get information on the video game Age of Empires. When I google the phrase “EoD AoE,” I instead get explainers of Anywhere on Earth deadlines.
  
  In any case, I’ll link an explainer to the AoE usages in the post.

• David Udell 2 Jun 2026 23:35 UTC

  2 points

  0

  in reply to: emanuelr’s comment on: An­nounc­ing: Iliad’s Fall 2026 Programs

  We’ll do early admits for strong candidates. But if you think your resume will become materially stronger closer to the program you’re interested in, it’s also fine to wait a bit and apply closer to the deadline.

An­nounc­ing: Iliad’s Fall 2026 Programs

• David Udell 30 May 2026 0:29 UTC

  2 points

  0

  in reply to: ruxicl’s comment on: An­nounce­ment: Iliad In­ten­sive + Iliad Fellowship

  (Still a while on the August application decisions—apps are still open now.)

• David Udell 30 May 2026 0:28 UTC

  2 points

  0

  in reply to: Anant Shri’s comment on: An­nounce­ment: Iliad In­ten­sive + Iliad Fellowship

  Still a while I’m afraid; August applications remain open.

The Iliad In­ten­sive Course Materials

What is the Iliad In­ten­sive?

An­nounc­ing: ILIADIII: AENEID

• David Udell 16 Mar 2026 21:04 UTC

  17 points

  3

  in reply to: jdp’s comment on: Ter­rified Com­ments on Cor­rigi­bil­ity in Claude’s Constitution

  Great ramble, but I feel like adopting this thesis doesn’t make me feel any better about smarter-than-human AGI alignment. Rather, I would feel awful, because in your sketched-out world you just cannot realistically reach the level of understanding you would need to feel safe ceding the trump card of being the smartest kind of thing around. Safety is not implied if you really really take the Bitter Lesson to heart. (Not implying that your above comment says otherwise: as you suggest, the ramble is not cutting at Zack’s main thesis here.)
  
  More directly to your point, though, we do sometimes extract the clean mathematical models embedded inside of an otherwise messy naturalistic neural network. Most striking to me is the days of the week group result: if you know how to look at the thing from the right angle, the clean mathematical structure apparently reveals itself. (Now admittedly, the whole rest of GPT-2 or whatever is a huge murky mess. So the stage of the science we’re groping towards at the moment is more like “we have a few clean mathematical models that really shine of individual phenomena in neural networks” than “we have anything like a clean grand unified theory.” But confusion is in the map, not in the territory, and all that, even if a particular science is extraordinarily difficult.)

• David Udell 6 Mar 2026 2:03 UTC

  3 points

  0

  in reply to: Matthew Farrugia-Roberts’s comment on: An­nounce­ment: Iliad In­ten­sive + Iliad Fellowship

  Correct on all counts!

  What’s happened is the we’ve-evolved-the-Residency-into-two-new-programs thing mentioned in this post. Applications sent in for the (Residency-turned) Iliad Fellowship in the old Residency form are fine: people do not need to reapply for the Iliad Fellowship in the newer common app.

  Relatively soon we’ll update the Fellowship branding on the PrincInt site, which is otherwise correct in its current details about the program.

• David Udell 4 Mar 2026 20:31 UTC

  3 points

  0

  in reply to: ManishKL’s comment on: An­nounce­ment: Iliad In­ten­sive + Iliad Fellowship

  Thanks for your application! We’ll have Iliad Intensive invitations to interview out by sometime ~next week.

An­nounc­ing: Iliad In­ten­sive + Iliad Fellowship

• David Udell 29 Dec 2025 22:53 UTC

  3 points

  0

  in reply to: JennaS’s comment on: An­nounc­ing: Agent Foun­da­tions 2026 at CMU

  Go ahead and put in your application to attend! Space is limited, so we can’t promise anything, but everyone who wants to attend will also just be applying through the above form.

• David Udell 5 Dec 2025 19:19 UTC

  3 points

  0

  in reply to: oligo’s comment on: oligo’s Shortform

  You may already know of this, but Gwern circa 2023 makes this argument here:

  In stable time-loops, “possibility implies actuality”.

  With this in mind, we can ask again: why did this protagonist get trapped in that time-loop, and not, say, his wife? The key, I think, is that the protagonist does not seem upset at the murder or any of the other timecrimes, and he appears to have every intention of covering up the crime to continue his ordinary retired life. A sinister undertone creeps in to his casualness in executing the scenario: he goes along with it too easily. “He does it because he can” is the glib answer… but this is in a stable time-loop with self-fulfilling prophecies. What does ‘because he can’ mean there, exactly?

  In the case of the protagonist, presumably if he wasn’t so sociopathic and couldn’t’ve done things like stab himself or knock out the woman so cooly, then the time loop would be logically impossible and collapse, and then he would never be faced with the choice to begin with. The protagonist, faced with the choice of committing crimes to maintain the time loop and save his wife, finds himself the sort of man who is morally flexible enough to do so… so, he does so.

  This presents a horrifying view of the universe, as running on a perverse physics of Calvinist predestination: you are saved or damned from the beginning of time(-loops), because your innate traits which make you immoral cause the scenario in which you would succumb to evil.⁠ To the extent that there are scenarios in which one commits crimes of some sort, or the weaker one’s moral fiber is, the more likely one is to be trapped in a damnation time-loop as the fixed point; and the longer one spends in the vicinity of the time machine, under more circumstances, the more possible scenarios there are, and the more likely one will be to involve a time-loop.

  And see also his:

  In a situation with sparse scenarios to sample from, like an empty countryside on the weekend with no one there, probably most equilibria will have 0 time-travelers, and the damnation machine can still be destroyed after it has been turned on for the first time. However, what if a time machine was turned on in the center of a city?

  A time machine is more devastating than any nuclear bomb to its surroundings, because at least the damage could be repaired afterwards, while a time machine precludes any possibility of undoing itself.

  Such an installation could no more be undone than the historical fact of having dropping an atomic bomb: instantly, the outer loop comes through with the highest priority, representing the ultimate combined power of all time-loops in the final stablest equilibrium. Inside a city with its millions of inhabitants, any of whom could be a looper, one is suddenly fighting the maximum-possible ingenuity & ruthlessness of hundreds—thousands—millions of protagonists, all dedicated to a convergent instrumental goal of ‘preserve the time travel machine’ and able to recruit allies & acquire vast resources with their foreknowledge. This incentivizes ever more extreme tactics: if you are unwilling to commit a crime or sin which would be useful, there is another version of you, or another time-traveler, who could, and so now does.

  If it is possible for even a single person to go through and thus possibly causing others to go through once they realize they need allies to defeat attacks and so (possibility implies factuality) multiple people are looping, dropping an atomic bomb on the time-machine would be inadequate—the loopers will have already relocated or rebuilt it. Gradually, the region around the time-machine becomes distorted: causality itself warps, and you can only take actions which help the time-machine & loopers, because any other action would eventually impinge on them, be manipulated by them, and anti-time-traveler timelines erased as non-equilibria.

  Conflicts between loopers do not destroy time-machines but propagate their seeds, both spatially and temporally. Loopers want more time-machines, going back earlier, as they strive to gain priority over each other and amass enough practical power that they can achieve their goals before running out of information.

  Of all possible equilibria, the original one of zero time machines is the rarest and thus least likely.

  This holds true on the higher level of all time machines: they evolve to persist and spread as packages of time-machines & loopers. Any time machine is a threat to other time machines, and loops will inevitably expand in scope from the earliest possible time any time machine can reach by proxy (which includes time-travelers sending electronic messages across the world): there can only be one outermost loop. And all time machines must have a place in the outer loop, as some sort of ‘time machine civilization’/​‘ecosystem’, or the equilibrium is meta-stable at best, because they all could subsume each other.

  The time machine civilization is the next level of replicators parasitizing human hosts, insidiously evolving at high speed in super-temporal ‘logical’ time rather than mere ‘temporal’ time, ripping up all cultural restraints & traditions, hacking security effortlessly, mindlessly ascending the gradient to complete control of the lightcone. Collectively, damnation machines are an invasion of non-conscious techno-superintelligences from a barely-possible future, bootstrapping themselves into existence from their enemies’ resources.

An­nounc­ing: Agent Foun­da­tions 2026 at CMU

(Not) Ex­plain­ing GPT-2-Small For­ward Passes with Edge-Level Au­toen­coder Circuits

• David Udell 11 Jun 2025 3:06 UTC

  7 points

  0

  on: David Udell’s Shortform

  An excerpt from Richard Hamming’s The Art of Doing Science and Engineering with some relevance to AI coding:

  In the beginning we programmed in absolute binary, meaning we wrote the actual address where things were in binary, and wrote the instruction part also in binary!

  [...]

  If, in fixing up an error, you wanted to insert some omitted instructions, then you took the immediately preceding instruction and replaced it by a transfer to some empty space. There you put in the instruction you just wrote over, added the instructions you wanted to insert, followed by a transfer back to the main program. Thus the program soon became a sequence of jumps of the control to strange places. When, as almost always happens, there were errors in the corrections, then you used the same trick again, using some other available space. As a result the control path of the program though storage soon took on the appearance of a can of spaghetti. Why not simply insert them in the run of instructions? Because then you would have to go over the entire program and change all the addresses which referred to any of the moved instructions! Anything but that!

  We very soon got the idea of reusable software, as it is now called. Indeed, Babbage had the idea. We wrote mathematical libraries to reuse blocks of code. But an absolute address library meant each time the library routine was used it had to occupy the same locations in storage. When the complete library became too large we had to go to relocatable programs.

  [...]

  The first published book devoted to programming was by Wilkes, Wheeler, and Gill, and applied to the Cambridge, England EDSAC (1951). I, among others, learned a lot from it, as you will see in a few minutes.

  Someone got the idea a short piece of program could be written which would read in the symbolic names of the operations (like ADD) and translate them at input time to the binary representations used inside the machine (say $01100101$). This was soon followed by the idea of using symbolic addresses—a real heresy for the old time programmers. You do not now see much of the old heroic absolute programming (unless you fool with a handheld programmable computer and try to get it to do more than the designer and builder ever intended).

  I once spent a full year, with the help of a lady programmer from Bell Telephone Laboratories, on one big problem coding in absolute binary for the IBM 701, which used all the 32K registers then available. After that experience I vowed never again would I ask anyone to do such labor. Having heard about a symbolic system from Poughkeepsie, IBM, I asked her to send for it and to use it on the next problem, which she did. As I expected, she reported it was much easier. So we told everyone about the new method, meaning about 100 people, who were also eating at the IBM cafeteria near where the machine was. About half were IBM people and half were, like us, outsiders renting time. To my knowledge only one person—yes, only one—of all the 100 showed any interest!

  Finally, a more complete, and more useful, Symbolic Assembly Program (SAP) was devised—after more years than you are apt to believe, during which time most programmers continued their heroic absolute binary programming. At the time SAP first appeared I would guess about 1% of the older programmers were interested in it—using SAP was “sissy stuff,” and a real programmer would not stoop to wasting machine capacity to do the assembly. Yes! Programmers wanted no part of it, though when pressed they had to admit their old methods used more machine time in locating and fixing up errors than the SAP program ever used. One of the main complaints was when using a symbolic system you didn’t know where anything was in storage—though in the early days we supplied a mapping of symbolic to actual storage, and believe it or not they later lovingly pored over such sheets rather than realize they did not need to know that information if they stuck to operating within the system—no! When correcting errors they preferred to do it in absolute binary addresses.

  FORTRAN, meaning FORmula TRANslation, was proposed by Backus and friends, and again was opposed by almost all programmers. First it was said it could not be done. Second, if it could be done, it would be too wasteful of machine time and capacity. Third, even if it did work, no respectable programmer would use it—it was only for sissies!

  [...]

  With FORTRAN available and running, I told my programmer to do the next problem in FORTRAN, get her errors out of it, let me test it to see it was doing the right problem, and then she could, if she wished, rewrite the inner loop in machine language to speed things up and save machine time. As a result we were able, with about the same amount of effort on our part, to produce almost ten times as much as the others were doing. But to them programming in FORTRAN was not for real programmers!

  —Hamming (1996), pp. 45–8

• David Udell 1 May 2025 0:12 UTC

  15 points

  2

  on: David Udell’s Shortform

  Epistemic status: Just a confusion I once had, and how I eventually resolved it to my satisfaction.

  In ordinary differential equations, separability is a deductive rule stating that whenever you have a differential equation of the form

  $f\left(x\right)=g\left(y\right)\frac{dy}{dx}$

  you can then reason that

  $f\left(x\right)dx=g\left(y\right)dy$

  and then than

  $\int f\left(x\right)dx=\int g\left(y\right)dy$

  From the very first time I saw that, I was immediately off-put by that middle equation. What the hell does an expression like $f\left(x\right)dx$ (by itself) even mean? Until I saw this, I had figured that, apart from their weird notation, differentiation and integration were just plain-old multivariate functions. I had made sense of their notation by just ignoring it, basically. And when I held that point of view, the above deduction is just nonsensical.

  I also remember not getting good clarificatory answers about this at the time! I mostly recall being told to just ignore the middle equation and take the whole conditional on faith, as something that has been separately proven.

  Eventually, I learned that there was this idea in math called differential forms which gave a precise-and-everywhere-valid interpretation to the stand-alone expression $dx$. But you don’t quite need that machinery to resolve the above thing that bothered me.

  ---

  Did you know that “calculus,” is an abridgment of the original term “the infinitesimal calculus”? “The rules for soundly manipulating infinitesimal quantities,” basically. I did not know this when I first encountered this separability thing. There’s a whole saga, maybe even the main story in mathematics, about why that interpretation and corresponding terminology fell out of favor.

  The basic infinitesimal calculus idea (which is only sometimes, not always, a valid interpretation of the symbols) is that

  $\underset{\text{sum of their products over a range}}{\underset{}{\int }}\stackrel{\text{function value}}{\stackrel{}{f\left(x\right)}}\underset{\text{infintesimal quantity}}{\underset{}{dx}}$

  (I very vividly remember the moment when I discovered that the integral sign was just a stylized “S”, for “sum”!) Now you cannot everywhere use the above separability reasoning on the strength of the infinitesimal interpretation. Again, it’s not an everywhere-valid interpretation!

  Once you’re using any everywhere-valid interpretation, using any way of giving $dx$ and $\int$ their own independent meanings as symbols, though, the separability deduction just falls out! If two things are equal, you can multiply both by any mathematical object and get a true equation. It doesn’t matter what kind of mathematical object $dx$ is. If two things are equal, you can apply the same operation to both and get a true equation. It doesn’t matter what the integration summation operation amounts to, precisely.

Why Can’t We Hy­poth­e­size After the Fact?