Two Answers

It's interesting to note that according to the written rules of Twenty Quest ions, 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.

Plenty Questions

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

See also: Negative Twenty Questions

Try also: Numerical 20 Questions where all questions have to be answerable with numbers, e.g.:

(Approximations are legal)