Having Trouble with Tantalizers?

During the 1970s I did a lot of work testing a heuristic problem solver called Tantalize - which was written in CODIL. The following news item was published in the New Scientist of 21 August 1975 and as I will be referencing this in the next blog post [insert link] I have decided to reproduce the original item.

For those who have trouble solving the Tantalizers that run each week in New Scientist, Dr Chris Reynolds of BruneI University has developed a computer programme.

"I'm sorry it can be done," commented Martin Hollis, a philosopher at the University of East Anglia, who creates the Tantalizer each week. "The best puzzles are the ones which are too elusive for a computer."

And some are too elusive.- Reynolds' computer can only solve about one-third of the Tantalizers: "It won't handle any which involve deep insight  those which are easy once you see the catch."

Reynolds has developed a new computcr language, Codil, which is designed to permit non-computer people to use the computer for information processing (as distinct from data processing). It is especially useful for projects which involve data base or record manipulation. (Tantalizers often involve just such information.) Codil does not make the standard distinction between program and data.

"Tantalize" is a problem solving package "designed to cope with open-ended poorly-defined problems, while ordinary computer systems deal with only precise problems," he said. Tantalize starts by asking questions about the problem. The user defines relationships, illegal conditions, and the goal. The program then searches until it finds a solution.

In Late knight extra, Tantalizer no. 407 (10 July, p 88), four knights have a set of attributes - colours of plume, banner and shield; degree of bravery; and name of horse. The question is which kight has the purple plume. The Tantalize user first types in the categories: knight, steed, plume. ete. Then the computer asks him to name the knights, name the steeds, and so on. Finally, it asks him to type in what he knows, for example "Knight=Sir Bruce: Steed= Geronimo". Finally. the user gives the goal, and the computer finds the answer.

Reynolds has solved more than 30 Tantalizers this way, and is still working on more. On Monday he solved the 7 August Tantalizer, no. 411 Diplomatic Niceties, about assigning the right ambassadors to the right countries.

Tantalize also permits simple arithmetic computations. On Monday, Reynolds also solved no. 409 Fe, Fi, Fo, Fum, (24 July, p 230) about giants with five, six, and seven league boots.

Hollis sees two types of Tantalizers.

In the first, the setting has nothing to do with the problem. Late knight extra is one of these, and Hollis first draws a skeleton and then sets the attributes. The second kind "depends on having the right thought in the bath." In these the location and characters are integral to the problem. I spin a web out of an idea. These are tricky and depend on things which seem irrelevant being not irrelevant at all."

Among those which Reynolds' computer could not solve was no. 365 Acknowledgements (vol 63, p 750) which depended on the definition of the word "pedantry", and no. 369, Find the catch about how many fish were caught by Hook, Line, and Sinker. The latter is mechanical in reasoning, Hollis said, but the problem is to see where to start.

Hollis himself prefers the latter kind.

"But doing them once a week, I'm afraid the computer has to be allowed a fair bite of them."

Joseph Hanlon