Apr. 25th, 2017

jack: (Default)
I realise I've had *another* shift in habits.

Now I'm keeping a daily/weekly todo list more as standard, any emails I need to reply to on a specific timescale get duplicated into that system.

But that means I've shifted to starring emails that need a reply, and going through them occasionally, and the rest of my inbox has gone back to being "everything I've received recently0-ish that might be relevant". But mostly without the problem of "agh the important emails got lost".

Of course, gmail divides that into five folders: primary; social media notifications; corporate mailing list type stuff, and a couple of others. I could do something similar with filters. But it would be harder to cope if those were all muddled together. Non-starred mail in primary tends to be "conversations which are relevant in the next few days but don't need a reply right now". I tend to use social media notifications for marking comments I'd like to reply to, although that's fiddly. And the others rarely need any action (if they do, it's usually important and I move it into primary).
jack: (Default)
After running a couple of roleplaying sessions with quad & family, I would like to try to run something regularly in addition to whatever I run with them. I'm probably going to aim for once a month depending on interest.

I'm going to start by running a lightly revamped version of the DnD 5e one-shot I ran for quad before.


Passengers on a ship, driven far out to sea in a storm and beached for repairs on an abandoned island. 30 years ago it was home to a pirate lord, Erik Twicecursed and his BFF Grignir Hammerhead. While repairs succeed, the captain asks for volunteers to explore the abandoned and reputed-cursed pirate lair.

There may be treasure. There will almost certainly be combat encounters. Hilarious misunderstandings of the skill system and trigger happy party wizards are not guaranteed, but likely.

DnD 5e. For people new to roleplaying I will give you a pregenerated 1st level character sheet but suggest you invent a character who's more interesting to you, and change any specifics accordingly. If you're familiar with the system you're welcome to generate a 1st level character however you like.


This Saturday 2pm. It may run into the evening, in which case we'll probably have pizza.

If you're interested, comment here or email me by midnight Fri, and I will send you directions. (North cambridge, but may be lifts available if transport is an issue.)

You don't need to bring anything. If you're excited to do so anyway, things that could be useful: bring 5e books if you have them; read a little about 5e online; think about a character concept, not so much detailed background, as what they like doing and how they might be connected to other characters (member of ships company? bodyguard? relatives?)

Also let me know if you'd be interested in future one-shots or campaigns.


I have a campaign in mind following this session, but think it makes sense to schedule several one-shots and see which people are interested in coming back to.

People were very enthusiastic about my putative vorkosigan campaign, and I would really, really like to run that, but it will not be this weekend, it needs more prep time. But if you're interested and think you could actually make time to come, please let me know. (If it happens I plan a series of connected stand-alone sessions, so I might well be able to run one if I'm in london for the day, even if other sessions take place with people in Cambridge.)
jack: (Default)
This has so much I love.

An interesting space empire, full of detailed calendrical minutae, customs, etc, etc.

A mathematically gifted protagonist struggling to serve loyally as a minor officer in the infantry.

A legendary rogueish maybe-monster.

The empire is built on basically mathematically-based magic, following particular social codes (both on an "infantry formation scale" and a "society as a whole" scale) allows various exotic technologies to work that wouldn't otherwise, including more powerful weapons and other tech that enables the empire to function at all.

I had some reservations too, which may contain spoilers, so will be moved into a follow-up post. Please make any comments which contain spoilers on that post too.
jack: (Default)
You should be able to select multiple pokemon from your reserves when choosing which pokemon to fight with.

When you're training a friendly gym, the default pokemon selection should avoid pokemon very slightly higher CP than the ones you're fighting that automatically reduce the prestige gained by 40%.

"Vaporeon used hydropump" should always come slightly before the special move takes effect, rather than slightly after.

If your pokemon is on 5% health and you switch to another pokemon and that one is knocked out, its default replacement should be the *next* one, not the one which will be knocked out instantly. (Is there a shortcut for "next pokemon" without going through the pokemon select screen?)

If your switch pokemon and while you're in the pokemon select screen, your previous pokemon faints or you forget which pokemon you started with, and you click frantically click a pokemon again and again trying to select it and nothing happens, it should select that pokemon even if it's the one already selected.

If you select "run away" there should be a quick gesture to do so in a single click, without needing to get to the "yes" button before your next pokemon is knocked out too.
jack: (Default)
Last post, I decided that what's "really there" for fundamental particles is typically a quantum thing, specifically, a probability wave of possible values a particle can have which appears to collapse into one particular place only when its interacted with.

However, this "collapse" sounds very suspicious. If two different particles emitted from the same particle decay (or something?) are known to have opposite spins, but not what those are, do you get all the usual wavelike behaviour, can each self-interfere, etc? Yes, of course. And yet, when you finally measure them, lo, the spins are still conveniently opposite.

Something that looks like collapsing to a single answer seems to happen, because when we measure them, we always do get a single answer. But that's not an event. If you measure one, does a spooky force reach out across the room to force the other to collapse at the same time? Does it collapse the value you measure, but still allow other properties of the particle to continue being multiple? That looks awfully like what happens, but it should seem wrong to start with, even before you ask "if you measure one particle, does the other know to wait until you interact with it, but store the answer you're going to find until then" and "if you measure them both a long way apart, does the collapse rush faster than the speed of light (aka backwards in time) to make sure both answers agree with each other?"

Any theory involving particles "knowing" or "waiting" or "choosing" depending on how you measure them sounds very unlike physics.

And yet, the particles go on behaving like probability waves until you measure them, and if they came from a shared source, then when you measure them, they DO agree. Just as if this spooky shit was happening. What might be going on?

Hypothesis 1

Whenever one particle collapses, a spooky force travels faster than the speed of light to the other particle, and then hangs around telling it what value it will have when it's finally measured.

This *works*, but hopefully you can see why it doesn't seem correct.

Hypothesis 2

Just like hypothesis 1, but we try to avoid thinking about it. This is not really satisfying, but it works and is a pragmatic default for many physicists. (Sort of Copenhagen interpretation?)

Hypothesis 3

Even while a particle is still smeared out across a probability of many potential positions/values, it has a hidden property which tells it how it's *going* to collapse when something interacts with it. Like, not necessarily "hidden", but basically some sort of determinism.

This is roughly Hidden variables interpretation (right?)

This would be fairly satisfactory except that it turns out it's impossible.

This is not very mysterious or controversial, but involves more simple probability than I can manage to wade through. Look up the EPR paradox or the Bell inequality. The idea is, you choose something like polarisation angle that could be measured at many different angles. You randomly choose to measure at different angles for two particles known to have opposite polarisation. There are various correlations between the probabilities when you measure the two particles at an angle to each other (the detectors neither parallel nor orthogonal). You can prove that no possible hidden value would make all those correlations true at once, but QM does and that's what's actually observed.

I can't really prove this to myself, let alone anyone else, but AFAIK no reputable physicists doubt that it's correct, only maybe what it means, so I'm willing to accept it as true.

There are still edge cases, like, people argue whether the experiments have ABSOLUTELY DEFINITELY proved this spooky collapse effect would have to go faster than the speed of light, rather than going at a possible speed (but depending what exact moment sets it off, etc). But I don't find any of that very persuasive. A spooky collapse effect which is triggered by measuring a particle and goes at the speed of light or below, while not ABSOLUTELY DEFINITELY ruled out, doesn't sound at all likely. I don't think anyone seriously expects that if they make the distance apart in those measurements a bit bigger, they'll suddenly get difference results: that's not how you expect physics to happen.

Hypothesis 4

Those weird quantum probability waves don't only exist for tiny particles, they happen just the same for everything including macroscopic objects, humans, etc, but you can't observe the effects except for tiny things (because to see interference you need something isolated from other particles, and you need to be able to detect its wavelength, which is way too small for anything bigger than a molecule).

I'm still working on understanding *why*, if that's true, it produces the effects we see. But most physicists, even ones who don't like this line of reasoning, seem to agree that it *would*.

This makes everything above non-mysterious. How does the collapse effect move around? It doesn't. Every "collapse" is just another probability thing of a scientist (and all the other macroscopic stuff) interacting with a particle and becoming two never-interacting possible scientists, one observing A, one observing B. We know both happen. We know, when we measure things light-hours apart and then compare notes, that we will be comparing notes with the version of the other scientist who observed the opposite polarisation to what we saw, while our shadow twin will be comparing notes with the other scientist's shadow twin.

The multiple non-interacting versions of the macroscopic world are called "many worlds" or "parallel universes" which admittedly makes them sound very implausible.

It seems like, this leaves some things to ponder, but resolves a very large part of the things people find mysterious. And yet, many physicists really don't like it. I need to read the bits of Scott Aaron's book about different interpretations[1], because I trust him to know more about this than me and he doesn't seem convinced.

Footnote [1]

The hypotheses above are called interpretations. I don't know if my ones exactly map onto the real ones. The name is because they all predict the same results, and yet seem quite different.

You can argue, "they're the same", but I don't quite agree. See for instance space outside our light cone -- we have no way of observing it, so the hypotheses "it's got physics just like ours but with different stuff there" and "it's all purple unicorns" are both possible, and yet, the first one seems a lot more like actual reality.

In both cases, it sort of doesn't matter, but you can imagine (a) which answer is most plausible, most useful, easiest to work with, or least ridiculous (b) if we're wrong and there IS some difference, which one would actually be found to be the one that exists.