It's interesting to note that according to the written rules
of Twenty Questions, you can play the whole game and still need only two
answers. Yes, No.
Many years ago, my friend David Thornburg
invited me to play 20 questions with a computer.
Is it Animal? I typed. No, it answered. Vegetable? Yes. Edible? Yes.
Is it Yellow? No. Corn? No. Is it Green? No. Red? No. White? Yes. (Aha,
a white, edible vegetable!) A Cauliflower? No. A Turnip? No. A Jicima?
Yes.
I was relatively impressed with the way the computer played. It certainly
picked a difficult enough challenge. Jicima!
And then Dave showed me the program. I think the whole game was written
in maybe five lines of code. In Basic. So how did it work, you ask?
How could such complex obscurity as a Jicima be programmed into a machine
with maybe five lines of code? In Basic?
Want to try it again?
Animal? No. Vegetable? Yes. Edible? Yes. A green vegetable? Yes. Does
it grow on the ground? No. On a vine? Yes. Peas? No? (Not peas? Green,
edible, on a vine. Grapes?) Is it also purple? Yes. Grapes? No. (Not
Grapes? What else could be green or purple, edible, and grow on a vine?)
Is it a particular kind grape? Yes. A wine grape? Yes.
All in five lines code!
One of which instructs the machine to answer No.
Another instructing the machine to answer Yes when the last letter
entered by the user is a vowel.
I was conned! It was a fake! The only intelligence I was really playing
with was mine. All I had to do to get a Yes from the computer was to
make sure that a vowel was at the end of my sentence. Rutabaga, broccoli,
spaghetti, Alaska, Europe. It wouldn't have mattered. What mattered
was the meaning I made out of it.
I think there's something here, at least twenty answers to probably
as many questions about the nature of games and the art of artificial
intelligence.
From: Jed Hartman
Subject: Plenty Questions
Heyo! I decided to peek at your Web site before getting down to Serious
Work. Seeing your column on Twenty Questions reminds me of a game that
my friends Ranjit and Dominus invented, called Plenty Questions. As
originally presented, it's as rigid a game (in some ways) as Twenty
Questions, but expansions and variations present themselves pretty clearly.
The original game goes like this: one person thinks of something. (It
usually works best if it's a relatively concrete thing, but in the first
game Arthur and I played he started by thinking of Patripassionism,
apparently an obscure Christian heresy -- an item I would never have
guessed, but it does show that abstract things can be thought of as
targets.) The other people (works *far* better with multiple guessers
than with only one) guess what the thing might be. The person with the
answer says only whether the guess is "hotter" or "colder" (or "warmer"
or "cooler" if you prefer) than the previous best guess. Of course "Hot"
and "Cold" are entirely subjective measures, but people can usually
guess the answer the answerer had in mind, or at least get remarkably
close. (If you get *too* close, it may be hard to find something warmer
than your best guess so far -- in which case you can start over from
scratch and try to guess the same answer from a different direction.)
As I said, there are lots of interesting variations, most of which
I've never actually played. But the original game can be pretty darn
fun all by itself; give it a try, and fun variations will no doubt present
themselves during play.
--Jed
