Around 1980, progress ceased and mankind took several paths in an effort to find new directions.

A good example is a student of ours-now the vice-president of the Xerox Corp.-called Daniel Bobrow, who in 1964-65 made up a program that could read a question from an algebra schoolbook and in some occasions come up with solutions to problems. So, it was able to detect and comprehend a bit of language along with some algebra. It could not solve most problems because it was unable to grasp the meaning of words. Those days, we’d been trying to make a program that could read a passage from a first or second grade elementary school textbook But the whole thing went like this: For every individual text, we had to include in the program all the knowledge it needed to read the specific text. We did not come up with many problems connected with grammar, but each time there was reference to something unknown to the program, the system collapsed…

An MIT student had a text about someone’s daughter who had been abducted by the Mob, ransom being asked. He asked the program: ‘What should we do?’ The program could not comprehend the question. He finally asked ‘Why must he pay money to get back his daughter?’ Then, the program was able to understand bits from the language and pieces from algebra. It did not understand texts as it was unable to comprehend the meaning of words.”

In the end, what really computers miss is the thing we call common sense. Yet, what is the so-called “common sense” in the final analysis?

“It is the ability to know about 30 or 50 million facts about the world”, says Marvin Minsky, “and have them arranged in such a way that will allow you to find analogies. Common sense won’t let you arrange things in a rigid order. You store them (in the brain) in accordance with their utility or what they might remind you of. For example, one can interpret a suitcase as an object that can be used to step up and change a light bulb instead of a means to carry things in…

A stick can be used to push things rather than pulling them. Using a line, one can pull things, not push them. This is what common sense is all about, but there is not a single computer in this world that is capable of mastering this piece of knowledge…”