Jach's personal blog

(Largely containing a mind-dump to myselves: past, present, and future)
Current favorite quote: "Supposedly smart people are weirdly ignorant of Bayes' Rule." William B Vogt, 2010

Caches are evil

There's an old joke in programming culture: "There are two hard things in computer science: cache invalidation, naming things, and off-by-one errors."

Up until this year, I don't think I've fully appreciated the first issue of cache invalidation, or cache behavior in general. But over the last few months I keep running into issues caused by poorly thought out cache systems. Some of them my own fault, most of them other people's.

I'm at the point where I'm going to treat anyone who proposes a cache with suspicion, and make sure they can answer all of the following questions clearly. Depending on their answers, there might be no good reason to make a cache right now, or at least not to make the simplest cache with no control mechanisms. As one example, memoization is a neat trick to show off function decorators / macros, but it offers no control over the cache, so you need to know if you're just using it for a trick or for something useful! So, before making a cache of any sort, consider:

See Full Post and Comments

How you might see some of the dead again

The atheist position is that we won't see people who have died again. I don't disagree. But that's not the same as saying it's impossible, with or without the supernatural. There's an actual chance that's greater than epsilon. But it's still very small, I think it would be unwise to hinge any hopes on it, or to mislead (as I think Kurzweil can do) that it's almost assured given better technology.

The supernatural possibility is of course possible. Perfect souls might exist separate from the body and somehow encode all memories and thoughts separately from the brain, perfectly, so that even if the body is brain damaged and lives on another 30 years, the soul, while retaining that, is fully self-aware and has access to all memories and thoughts across all of its existence, and so is unharmed. And it may be that souls are reborn, or that they go have a party together after leaving their bodies, and remember each other (perhaps even across multiple lives if there is some rebirth before the party). Maybe that party's just the pre-party and once enough people arrive they all come back to Earth (some of them having just left!) in new bodies to have the real party. There are many ways, if you grant supernatural possibilities, for you to see the dead again, either while you're still alive or when you too die. Atheists could be wrong. But probably not. So that leaves us with the natural possibility. How might a form of resurrection work?

Is your grandparent the same person they were when they were in their late 20s? If your grandparent suddenly develops Alzheimer's and seems to lose many long term memories, but isn't all the way gone yet, are they still the same person? If they develop into full-blown unable-to-care-for-themselves Alzheimer's, brain cell death and all, are they the same person? If a cure is developed for Alzheimer's before they get to that point, and they receive the cure, so they stop losing long term memories and can form and retain new ones, are they the same person?

See Full Post and Comments

Irrationality is not necessarily bad

I'm slowly working through finishing The Waking Dream, which was assigned in a college class and I read maybe 70% of back then. The thing about it all that sticks with me is the idea of how differently our ancestors used to think about the world, and how remnants of that mode of thought in fact still are common today.

Rationality in the epistemic sense is about seeing the world as clear as you can, mathematically, given what you've seen of the world. This doesn't mean perfection. Rationality is about observing one white swan, then two white swans, then three, and therefore surmising that there could be more swans. And if there are more swans, you should expect the next one's color to be white, with odds of 80% (under Laplace's Rule, $$\frac{s+1}{n+2}$$) against not-white. A hundred white swans seen, you can expect the next to be white at 99%. This doesn't mean the next one won't be black!

Suppose you did make this into a bet, with two people and yourself as the intermediary. One of them only reasons rationally, the other one reasons in their own irrational way. Both have only seen 100 swans. The rationalist bets $99 that the next swan you bring out is white, the irrationalist bets $1 that it is black, not merely non-white. The rationalist should be pretty happy -- there's a 1% chance the next could be any other color besides white, thus there's even less than 1% chance that it's any specific color! Why is the irrationalist taking this poor bet? They claim because they saw a frog devour 10 flies that morning and that is a symbol that black is coming.

See Full Post and Comments


Finally got off my butt and used Let's Encrypt to add an HTTPS cert to this domain. Woot!

Non-HTTPS links should redirect to HTTPS ones, but this may change in the future if for some odd reason I think it should.

See Full Post and Comments

No longer bored of color

With thanks to Vox Day's theme that I shamelessly cribbed colors from.

The diff wasn't very much, the power of CSS. Only had to add a bit of new markup.

Still a bug with the first comment and last comment on a page with comments. They should have rounded borders. I thought first-child and last-child would work but it wasn't working, so maybe some other time I'll figure it out. Dumb with first-child/first-of-type. Anyway, PHP hack to the rescue.

See Full Post and Comments

Syria doesn't matter, but chemical warfare does

Suppose this whole drama in the news is a fabrication. Or at least that the use of chemical weapons is a fabrication. If so, then none of it really matters, Syria will still be in more or less the same state as it was a month ago. Even if Trump doesn't uncover the fabrication, it seems unlikely he would authorize a troops-on-ground war with the Syrian government. Tensions with Russia would increase, probably, but I also think war with Russia is unlikely at the moment. (If I'm wrong, I'll likely be dead, so nyah.)

Suppose the chemical attacks were ordered by Assad. This doesn't mean Assad must go, but the rest of the world (not just the US) must respond. Chemical warfare cannot be allowed to escalate.

Suppose the attacks were ordered by US state department employees, or Turkey, or some other government. This doesn't mean those employees or countries must go, but the rest of the world (not just the US) must, again, respond. Why not in the same manner?

See Full Post and Comments

Ghost in the Shell 2017 meets expectations

But I like to think my expectations were well-calibrated. So while I neither liked nor disliked the movie, it satisfied me.

I overheard someone leaving the theater they didn't like it. Too much focus on personal relations and nothing on philosophy. True, but why was anyone expecting a Hollywood flick to go full-GitS philosophy on its audience? Similarly I know some people were expecting Tachikomas, but did they ever see the first movie? Tachikoma-free. As was this one, so they'll be disappointed, due to their expectations.

Scarlett Johansson was a ridiculous casting for the Major. It's most prominent when she's paired up with Motoko's mother, an actual Japanese woman. But I'm also just kind of sick of her in things which is my main complaint about her. Still the actress not being Japanese is a valid criticism. While one might say the Major is a cyborg and it doesn't matter what she looks like on the outside (indeed she's had multiple designs in the animes), you're ignoring the anti-Western themes of the original material. Anyway my dislike of the lead is something I accounted for going in.

See Full Post and Comments