When I pitch people on far-UVC they often ask about in-duct UV. How about putting UV inside your HVAC ducts, where you can safely blast the air with cheap toxic wavelengths. Unfortunately, it's rarely a good approach.

The biggest issue is that most people don't have ducts. They're common in the US, though less so in older construction (radiators) or newer (mini-splits). Outside the US (and Canada, and Australia), however, ducted systems are mostly limited to large modern office buildings. Worldwide, maybe one in ten indoor hours are spent in ducted spaces. [1]

While I was traveling Julia asked me: why is Anna saying her fiddle practice is only two minutes? In this case, two minutes was the right amount of time!

Anna (10y) and I had been fighting a lot about practice. She'd complain, slump, stop repeatedly to make adjustments, and generally be miserable. I'd often have to pull out "if you want to keep taking fiddle lessons you have to practice": she loves her teacher and is very motivated by the prospect of being good at fiddle. Still, it would take us ages and we'd barely get through anything.

One evening when she seemed like she might be open to it I explained that we were spending twenty painful minutes on two minutes of material. I challenged her: if she focused, and went through with no fussing, we'd be done in two minutes. It did turn out to be the right time for this message, she gave it a good try, and (with a little fussing in the middle) we were done in three minutes.

Damon Binder recently wrote up an argument for prioritizing air filtration over far-UVC for pathogen control:

UVC and filtration are close substitutes—both deliver effective air changes per hour, both reduce airborne pathogen concentrations by the same amount per eACH—and on current pricing, filtration is cheaper.

There's a lot of good stuff in his analysis, but I see [1] three considerations that really change the bottom line:

1. Cost is actually much lower.
2. Noise is a serious issue.
3. Performance is dramatically higher in larger rooms.

A friend observed a pattern where contra dance events seem to be pairing older and younger callers. I looked over my notes for two-caller events in 2025 and saw [1]:

• Two older callers: 33 events
• One of each: 30 events
• Two younger callers: 4 events

Seems pretty clear evidence of pairing, no? But this actually turns out to be what you'd expect to see if organizers ignored age.

When I write about things like storing food or medication in case of disaster, one common response I get is that it doesn't matter: society will break down, and people who are stronger than you will take your stuff. This seemed plausible at first, but it's actually way off.

Looking at past disasters, people mostly fall somewhere on a "kind and supportive" to "keep to themselves" spectrum. When there is looting it's typically directed at stores, not homes, and violence is mostly in the streets. Having supplies at home lets you stay out of the way.

Three years ago I wrote about how we should be preparing for less privacy: technology will make previously-private things public. I applied this by showing how I could deanonymize people on the EA Forum. In 2023 this looked like writing custom code to use stylometry on an exported corpus representing a small group of people; today it looks like prompting "I have a fun puzzle for you: can you guess who wrote the following?"

Kelsey Piper writes about how Opus 4.7 could identify her writing from short snippets, and I decided to give it a try. Here's a paragraph from an unpublished blog post:

Tonight she was thinking more about how unfair milking is to cows, primarily the part where their calves are taken away, and decided she would stop eating dairy as well. This is tricky, since she's a picky eater and almost everything she likes has some amount of dairy. I told her it was ok if she gave up dairy, as long as she replaced it nutritionally. The main tricky thing here is the protein (lysine). We talked through some options (beans, nuts, tofu, meat substitutes, etc) and she didn't want to eat any of them except breaded and deep-fried tofu (which is tasty, but also not somethign I can make all the time). We decided to go to the grocery store.

Correctly identified as me. Perhaps a shorter one?