Wednesday, June 8, 2022

The Zen of Feeding the Birds

A gentleman on the cambridge subreddit is annoyed by his neighbour throwing stale bread into a public garden. My reply:


I found that when I lived in London, I used to get annoyed by the regular rapes and murders. When I moved back to Cambridge, I got annoyed by parking permits and traffic and tourists. When I hid out in Wicken Fen in the perfect peace and stillness of the pandemic, all alone for weeks with nothing to do but read and play chess, I eventually developed an almost magical-seeming ability to get annoyed by birdsong and the sound of the wind in the trees.

There is always something to get annoyed by. Usually the best way to deal with it is to find a way to deal with your habit of getting triggered, which is something that slowly develops like any other habit.

And you can fix that like you can fix any other habit. When rational and calm, work out what someone who wasn't annoyed by that sort of thing would think about your trigger (oh, how kind of that nice man to feed the birds!) , and then practice exposing yourself to the trigger and automatically starting off your desired new thought pattern.

It takes practice, but if you work at it, you'll eventually stop being annoyed. And then you'll have the superpower of being able to live free and calm in a place where annoying things happen.

Thursday, May 19, 2022

Assisted Suicide

Scott Adams wished his father dead: (https://www.scottadamssays.com/i-hope-my-father-dies-soon/)

And this paragraph stuck out for me:

If you're a politician who has ever voted against doctor-assisted suicide, or you would vote against it in the future, I hate your fucking guts and I would like you to die a long, horrible death. I would be happy to kill you personally and watch you bleed out. I won't do that, because I fear the consequences. But I'd enjoy it, because you motherfuckers are responsible for torturing my father. Now it's personal. 

I absolutely endorse this sentiment. If you are such a politician, I would very much enjoy gutting you with a rusty fruit knife. And I'm not even angry yet. My parents are still alive, still in good shape, still happy; for now.

I would nevertheless like to recognize the honourable behaviour of Lord Rix, who fought against assisted suicide his whole life, and then, right at the end, facing the horror himself, admitted he was wrong and publicly changed his mind. 

That is a very brave thing to do. He still deserved everything he went through, but I would pray for his soul if I thought it would help. 

The rest of you can go to Hell and stay there. For a lengthy, yet finite, time. I am not as evil as your God.

Saturday, May 14, 2022

Favourite Science Fiction

r/scifi asks us:

"What are your alltime top five science fiction novels"

https://www.reddit.com/r/scifi/comments/upaxq8/what_are_your_alltime_top_5_scifi_novels/

** Top Five (in no particular order):

  • A Deepness in the Sky
  • Protector
  • Permutation City
  • Blindsight
  • The Sparrow

** Runners Up for Top Five (again in no order, but none of these displace one of the top five for me):

  • Children of Time / Children of Ruin
  • Foundation (and the rest of the trilogy)
  • Dune
  • Flowers for Algernon
  • Seveneves
  • The Worthing Saga
  • The Mote in God's Eye
  • Anathem
  • Marching through Georgia (and sequels)
  • Most of Larry Niven's early stuff, none of his later stuff, plus several of the Man-Kzin Wars stories 
 
** Not novels, but nicely mind-blowing in the way that good novels are:
  • That Alien Message (Eliezer Yudkowsky) 
  • Lena (by "qntm")

** Interpreting SF rather broadly to include fantasy series that are nevertheless set in worlds with consistent rules

  • A Song of Ice and Fire / Game of Thrones and sequels.
  • Lord of the Rings / Fellowship of the Ring and sequels
  • Liveship Traders / Ship of Magic and sequels

** And finally, on the basis that these were science fiction when written (take our best theory of the world and run with it) but have become fantasy over the years, and also that they can get away with not being novels because novels weren't a thing:

  • Paradise Lost
  • Inferno
  • The Odyssey
  • The Aeneid
  • Agamemenon
  • Iphigenia at Aulis
  • The Bacchae
  • Metamorphoses

---------------------------------------------------------------------------------

It was a good question! And I rather got into it.

For me, the books on the list above have something transcendent and poetic about them, as well as having the essential speculative fiction characteristic of being set in very well thought out, believable worlds where an idea is taken seriously and the implications are followed up.

Of the two, I prefer the second characteristic to the first, but if you get both, that book's a real work of art.

All of these stories have changed the way I think about the world, both in the intellectual sense of pointing out things I didn't know about things I already knew, and in the emotional sense of altering my reaction to things.

 

 

 

 

 

 

Sunday, April 3, 2022

Deathbed Conversion

Turns out Group Theory's really neat, with lots of pretty diagrams and cool intuitions and beautiful theorems. (Disclaimer, only gone as far as the Sylow Theorems, but still...)

This unexpected revelation came to me through Nathan Carter's 'Visual Group Theory', possibly the most readable maths book I've ever come across.

https://www.amazon.co.uk/Visual-Theory-Classroom-Resource-Materials/dp/1470464330/ref=sr_1_1?keywords=visual+group+theory&qid=1648992100&sr=8-1

Despite being readable, I would say 'un-put-downable', it's a proper maths book. You need to do the exercises. Don't go on to Chapter 2 until you've done all the exercises from Chapter 1, etc. 

The most common complaint is that it's too slow at the start, too fast at the end. This is not true. The slow bits at the start are building your intuition by playing around with simple cases. 

You'll end up being able to flip between algebra and geometry and graph-theoretic ways of looking at groups.

Towards the end, real theorems start appearing, the ones you'd get in a first-year undergraduate groups course, and when you look at them through all the new lenses you've acquired through the early part of the book, they're obvious and beautiful. That's kind of the point of the book. 

You're only allowed to complain about how hard chapter 9 is if you've actually done all the exercises in chapters 1-8. 

If you find yourself in that sort of position and can make it to Cambridge, get in touch! I can explain everything I've read so far, and will happily exchange in-person supervisions for coffee in pub gardens.

--------------------------------------------------------------------

Other helpful things I've used over the last few months of fascinated exploration are: 

 

 

The errata page: http://web.bentley.edu/empl/c/ncarter/vgt/errata.html

Actually the fact that there are errors in the book has made it more fun.

Sometimes you find something in the book that seems a bit fishy. After you've thought about it for a while, you can usually make it make sense, but if it still doesn't, it's probably been reported as an erratum by now, so you can go and check. (Also, I managed to get one in myself! The pride! The glory!)




The wikipedia definition of semi-direct product: https://en.wikipedia.org/wiki/Semidirect_product

I could not make head or tail of Nathan's notion of 'rewiring diagram', so I couldn't get more than the vaguest sense of what a semidirect product was. 

So I ended up working out how the semidirect product works in an algebraic sense. *That* requires knowing what an automorphism is, which is not a terribly difficult concept, and it turns out that 'rewiring diagram' is an excellent way of visualizing automorphisms. 

You can probably shortcut this process by just working out what an automorphism is and how it relates to Nathan's rewiring diagrams.

 

 

An online implementation of the Todd Coxeter coset enumeration algorithm:

https://math.berkeley.edu/~kmill/tools/tc.html

It's a very good idea to learn how to do this by hand, and the best way is to read Todd and Coxeter's initial paper. 

Todd, J. A.; Coxeter, H. S. M. (1936). "A practical method for enumerating cosets of a finite abstract group". Proceedings of the Edinburgh Mathematical Society. Series II. 5: 26–34. doi:10.1017/S0013091500008221. JFM 62.1094.02. Zbl 0015.10103.

All modern explanations of it are incomprehensible.

However actually doing it by hand gets old pretty quickly, so getting a computer to do it is really useful if you just want to explore.

 

 

A page of small-group Cayley diagrams:

http://www.weddslist.com/groups/cayley-31/index.html


Sunday, February 13, 2022

The Unmitigated Pedantry of Bret Devereux

I have over the last few months derived great pleasure from the blog of Bret Devereux, an academic historian interested in military history, the classical world, and speculative fiction. He is a sufficiently good writer that he can make subjects I'm not particularly interested in (ancient steel-making processes???) seem fascinating and important. And of course some of his major interests are at least minor interests of mine.

In almost every one of his posts, he requests that people spread the word about his blog; he wants a large audience. 

I am more than happy to oblige him and unreservedly recommend:

https://acoup.blog

 

 

Sunday, January 30, 2022

The Proof of Doom



Epistemic Status: Ravings

Importance: Easily the most important problem in the world.

If we can escape the proof of doom, we will likely also solve all our other problems as a side effect, and all that remains will be the fundamental limits. Our new questions will be things like "How much joy can the universe physically support?"




It seems to me that the world, and everyone in it, is doomed, and that the end is considerably nigher than I might like.

To be more specific, I think that we may well create an Artificial General Intelligence within around 20 years time, and that
that will be our last act.

The newly-created AGI will immediately kill everyone on the planet, and proceed to the destruction of the universe. Its sphere of destruction will expand at light speed, eventually encompassing everything reachable.

There may well be more proximal threats to our species. Comets are one obvious one, but they seem very unlikely. Artificially created universally fatal plagues are another, but perhaps not very likely to happen within the next twenty years.




I've believed this for many years now, although my timescales were longer originally, but it seems to me that this is now becoming a common belief amongst those who have thought about the problem.

In fact, if not consensus, then at least the majority opinion amongst those mathematicians, computer scientists, and AI researchers who have given the subject more than a few days thought.

Those who once were optimistic seem pessimistic now. Those who were once dismissive seem optimistic.

But it is far from being even a mainstream opinion amongst those who might understand the arguments.

Far, even, from rising to the level of a possible concern.

Amongst my personal friends, amongst people who would mostly take my word on technical and scientific issues, I have found it impossible to communicate my fears.

Not all those who are capable of pressing the suicide button understand that there is a suicide button.





What to do?

One might empathise with Cassandra. A vision of flame, and no-one will believe.

Cassandra had many opportunities to save her city, but the curse of Apollo rendered her unable to communicate with her fellow citizens. Those of her cohort who independently sensed danger were individually obstructed by the gods.

We operate under no such constraints.

Our arguments are not clear.

My attempts to communicate the danger involve a complex argument with a series of intuitive leaps.

Any given interlocutor will balk at a particular hurdle, and write off the entire argument.




Consider a toy example.

Until very recently I did not understand Fermat's Christmas Theorem ( https://thatsmaths.com/2014/12/25/fermats-christmas-theorem/ )

I considered it one of those tedious facts that number theorists always seem fond of.

I think if someone had shown me the 'One Sentence Proof': (https://en.wikipedia.org/wiki/Fermat%27s_theorem_on_sums_of_two_squares#Zagier's_%22one-sentence_proof%22)

then I might have been able to understand it. With a lot of effort.

But I am reasonably certain that I wouldn't have put the effort in, because it wouldn't have seemed worth the trouble.

Just before Christmas, a friend encountered in a pub showed me a couple of examples of the 'windmill argument', which make the central idea of that proof visual.

We couldn't actually finish the proof in the pub, but the central idea nerd-sniped me, and so I played with it for a couple of days.

And at the end of it, I was convinced of the truth and of the beauty of the theorem.

I now think that I could explain it to a bright ten-year old, if that ten-year old was curious enough to play with pictures for an hour.

I'm considering writing an xscreensaver hack to illustrate it.

I still don't care about the result itself. But the beauty of the proof makes it a result that sparks joy.




That's what a proof is. Not a vague collection of intuitions. Not an obscure collections of symbols and formal manipulations.

A proof is, quite simply, an argument strong enough to convince a listener of its conclusion.

We need a Proof of Doom.




The proof must live, must be unanswerable. Must be clear.

Must be simple enough to convince anyone capable of bringing about the apocalypse that there is an apocalypse to be brought about.

A version full of greek letters would be nice to have in addition, such things tend to be more amenable to automatic verification.

But what we need is something that will convince a human mind without too much trouble. Every step must be interesting, must be compelling. Must be clear.


And I may be wrong. Perhaps the fact that almost no-one agrees with me and that I can't convince anyone is a sign that I am wrong. It has happened before. Maybe my argument is not sound. Maybe it is mostly sound, but there are loopholes.

Attempting to prove the truth of an idea is often a good way of showing that the idea is false.

By the Father and the Bright-Eyed Girl, would that this idea were false.


Excuse me Brother, have you let the Reverend Bayes into your life?

The Onion spoke wisely:


https://www.theonion.com/cdc-announces-plan-to-send-every-u-s-household-pamphle-1848354068


And in response someone on reddit said:


Can you share an example of the way it changed your worldview? I did not experience a similar perspective shift when learning the same material, and I'm curious if there's something I've missed out on.


To which my reply was:

 

Principally for me the idea that there can be several possible underlying explanations for a thing, and that rather than choosing one, you should keep them all in mind, and shift credibility around amongst them as evidence comes in.

E.g. what am I rolling? 6 3 2 1 7 3 3 2 .....

What will you bet, and at what odds?

 

This then attracted the (very good) reply:


1 shows you're rolling a single die, 7 shows it has at least more than 6 faces, assuming a standard polyhedral die it has to be at least a d8 but with no result higher than a 7 it is extremely unlikely to be a d20 and somewhat unlikely to be a d12 (although that is far to short a sequence to be certain) so I would bet it's a d8... at what odds, without breaking out my calculator I'd say its 75% d8 22% d12 3% d20

Which to my mind shows exactly the sort of thinking that I think is the major benefit of learning a bit of Bayes.

So at that point I felt that it would be nice to give my own fully worked out answer to the question:

(which is just completely the obvious answer so if you can already do this, don't bother reading it or do it yourself and see if you agree with me)

 

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