Friday, March 05, 2010

Strange Self-Referential Paradox in the Racing Rules of Sailing

Thanks to Jos (who writes the best blog on the planet about the Racing Rules of Sailing) for drawing our attention to a strange paradox in the Racing Rules.

It's in Rule 18, the Rule that applies at marks, the one that says when you have to give another boat room to round the mark. All racing sailors know the basics of this Rule: you have to give room to a boat clear ahead or inside of you. But Rule 18 is actually quite complicated. It has lots of sections and subsections. Rules mavens can argue for hours about 18.2(b) and 18.3(a). If you like that kind of stuff you will love Jos's blog Look to Windward.

I won't bore you with all the details, so here is a highly summarized version of Rule 18.


18.1 Rule 18 applies when blah blah blah. It does not apply
(a) in this situation
(b) in some other situation
(c) in yet another situation
(d) or even in this one.

18.2 Blah blah blah
18.3 More blah blah blah
18.4 Yet more blah blah
18.5 Even more blah blah blah.

So Rule 18.1 lays out four situations when Rule 18 does not apply. But if Rule 18 does not apply, then Rule 18.1 (which is part of Rule 18) does not apply either. So Rule 18 does apply. But then Rule 18.1 applies so Rule 18 does not apply....

My head hurts just thinking about it.

It's a typical example of how a statement that references itself can create a logical paradox.

Another example would have been if God had written the Ten Commandments slightly differently on those tablets of stone he gave to Moses. Think about what would happen if He had carved in stone these words...

7.1 Thou shalt not commit adultery.
7.2 Commandment 7 shalt not apply if the woman is really hot and your wife is out of town.

If 7.2 applies then 7 does not apply in which case it's not adultery. But wait, if 7 does not apply then 7.2 does not apply either so 7 does apply. So you're going to hell anyway buddy. Or are you?

All I can say is that God was smarter than the drafters of the Racing Rules of Sailing.


Baydog said...

I think I understand, kind of. If the boat is inside and overlapping, you must give room. However, the boat clear astern has no room, unless he or she knows that you cheated on your wife while she was out of town, in which case he or she does get room. Plenty of room. What if she was just out shopping, not so much room?

O Docker said...

This is not a comment.

Tillerman said...

Please ignore all comments to this post, including this one.

Carol Anne said...

This statement is false.

puzzled student said...

Is it a Rule that every Rule has an exception?

God said...

The RRS are the worst things mankind hath created since that golden calf thing. To teach you a lesson, I made frostbite racing.

Jos said...

Dear God, I thank you for the loose water today. It was very cold.
By worshipping that false religion at least I know I'm going to a warmer place.

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