Steve is incredibly thoughtful about the art of programming. He has written a lot of insightful commentary over the years. A highly recommended read.

Steve inspired us to build a val.town-like platform Gitlip (https://gitlip.com/) in early 2025. We quietly stopped working on it about a year ago because it was difficult to get paying customers.

It could have military applications; it's hard to imagine any civilian applications.

in theory it could avoid car crashes in practice the dudes that buy these cars will probably cause more crashes;)

At least the fans will allow for really short breaking distances.

I historically argued for a sort of horror-vehicle that would achieve autonomous driving "early" by exploiting downforce from powerful fans, but I mostly imagined it being used for autonomous deliveries and never imagined there being people inside it.

idk about the safety of involving jumping cars into car crashes, I'd still prefer the brakes (obviously not always enough time). The one useful situation I could see is if you're driving (accidentally I hope) off a cliff.

Beautiful writing style. So light, still eloquent.

Really? The writer seems like a piece of work to me. Half the post is bragging, a big chunk is insinuating bad qualities at peers and superiors.

> "so I asked the chatbot like my friends recommended, and, again, it said some bullshit"

And I'd give this a pass without the self aggrandising, since ChatGPT is a bot, but IMO downplaying something that was said without the original wording being available it is a very bad sign in a person. It pays to be specific when complaining about something someone else said. In a bot, I mean OK but I predict the author does this with humans too.

EDIT

> ...to which she accused me of trying to plagiarize her work and started ignoring me completely, and telling other people I was trying to copy her. Our friendship was never the same after that.

Yeah, like what she does here. I'd like to know what this friend said. I suspect there is a missing chunk to the story.

The existence of an undiscovered soundness bug doesn't make everything proven in Lean illicit. The proof would have to exploit the bug. People build houses on sound foundations even though the tectonic situation under them might not be sound.

> Because of these properties, the final backstop has to be humans...

The post has clearly stated that the work on Lean's underlying metatheory is not done, and requires more work. It's not inconceivable that computer formal verification could reach the trustworthiness of math itself.

> The existence of an undiscovered soundness bug doesn't make everything proven in Lean illicit. The proof would have to exploit the bug.

Yes, correct. The proofs would have to be checked to make sure they don't exploit the bug.

> computer formal verification could reach the trustworthiness of math itself.

Yes, it could. I don't think that is currently the case.

It's just turtles all the way down. This is not different than the fact we know as programmers there are bugs in the tools and compilers we use, they get fixed over time but more bugs remain. It is frustrating to realize that we aren't on solid ground like we want to be.

Do you trust the result of your c++ program is correct? Because there are bugs in every compiler, language. You passed that million test correctness checker on the new version of the compiler, but it didn't catch everything.

When a bug is fixed, you don't immediately retry all existing results from your application program. Maybe you would if the bug was in some area you know was important and exercised by your code, say you were adding and multiplying numbers and bugs were found in that area.

The checker has a bug, the compiler the checker was testing had a bug, your own code that was compiled by the compiler had a bug probably. There can be bugs at any layer.

> not inconceivable that computer formal verification could reach the trustworthiness of math itself

Not entirely sure what you mean by this, but every interpretation I can think of is AFAIK (I am not a mathematician) indeed inconceivable by Gödel's incompleteness theorem. As the article says the only thing it's mathematically possible for us to get out of formal verification is a proof of consistency relative to (i.e. assuming the soundness of) some other system. As far as formal verification of "math itself" is concerned it's turtles all the way down.

Edit: Oh, do you mean that we could come to trust formal verification as much as we trust (well established) maths generally? That's a different speculation entirely and not an objective or well specicified one. There are plenty of people on this site who already trust a Lean proof more than a traditional one, without understanding either.

Isn't it the case that planes mostly fly because the wing has an angle of attack? (a fighter jet has no problem flying upside down)

Yes. The point of the airfoil shape is to make flying more efficient, i.e. the engine would need to generate much more power if the wings were flat slabs, but the plane could still fly given a big enough engine.*

*Assuming the "big engine" wasn't so heavy that it made flight impossible because of its weight.

It may be. Indeed how do helicopters even fly.

But the point is that Lean formalisation is a new bar for engineering and for physics and abstract math.

Your probability distribution should be flatter at least.

Ridiculous CC bug I encountered, that others have encountered as well: I asked Fable to review a commit. Suddenly my Fable quota for the week was at 100%, while a moment ago it was at 55%. A few days pass (1 day before the weekly reset) the quota resets back to 55%. ?!?!?!?!