Robhu: in response to atreic's post

Rob, I assumed you wouldn't mind me cross-posting this. It's a continuation of what I asked when you realised you wanted to be Christian, inspired by atreic's post. I didn't want to assume what you did think, but wanted to ask (and sorry for putting you on the spot).

I said to rob in his 'I have become Christian post' that I thought it was probably good that he is Christian, but that if that was based on conviction and observation, then I didn't see it need change his mind on, eg. when having meaningful non-marital sex is ok, or what has a soul. I know some people have very good reasons for some or all of those things, but they're not a necessary part of Christianity. Indeed, I should probably ask him directly *crossposts*.

ETA: some or all of what I thought rob thought was garbled and incorrect, I apologise for not checking first!

I get the impression you have changed your mind on several similar issues, for instance the post-fertilisation contraception atreic linked to. Do you think that's right? Obviously believing in God could make you consider the question more closely, but I get the impression you accepted things as part and parcel of believing in God maybe you didn't need to. Do you know what I mean?

To infinity and beyond

I've spent all day thinking about this now, and not got that far, because go is a game of unsurpassed depth and subtlety, and my head hurts :) In any game where each player acts in turn, and it's possible for a sequence of moves to repeat, the rules have to face the question of what to do if the players get stuck in a loop.

In Magic:TG there are complicated but well-defined set of rules which invite you to compare them to either conceptualised rules "what would happen if you could repeat the sequence infinitely many times" or "what happens if it went on and on, but one player had to break out of the loop eventually". (These are often discussed, eg. on toothywiki.)

In magic the situation is complicated by it sometimes mattering how many times you went round the loop (eg. if you can repeatedly put a new creature into play, can you end up with infinite creatures? Or an arbitrarily large amount?) But it occurred to me, the rules are essentially doing the same job as the ko rule in go or the three-repeats-or-fifty-reversible-moves-is-a-draw rules in chess.

In chess or go, going round the loop multiple times is the same as going round it once, so if you ever break out of the loop, it's the same as doing so at once.

How do the actual rules in place compare to what would happen if you could endlessly repeat?

( Chess )

To infinity and beyond and beyond

Infinity rules in go

Any go rule is generally either universal, or divides rulesets into three groups[1] which play the same in practice: one which ignores it; one which uses a big ban-hammer to make it deterministic, but proponents of the third interpretation think is anaesthetic; and one which defines it terms you can only understand if you already have a good go player's intuition about the game.

1. The "ko" rule This says that you cannot immediately repeat a board position. If black places a stone at a, capturing a white stone at b, white cannot immediately place a stone at b, if this captures the black stone right back again.

This is a venerable part of the game of go, and any alternative interpretation has to be equivalent to it.

Although it would be interesting to see if any of the alternatives would make sense. How would go change if the "ko" rule said that the first player could not repeat the ko position? That would favour a defender rather than an attacker. Or the chess rule allowing a player to claim a draw (or equivalently, letting the ko repeat forever). That would mean the player in the stronger position would be unable to play in the ko.

( Superko rule )