UNDERSTANDING AND RESPONDING

At first glance, if a computer program gives an appropriate reply to an input, then the program has understood what was required of it. This would be an erroneous deduction to make. Responding in an appropriate manner does not imply an understanding. Rather it may simply be that a programmed response was given to a recognisable input. Slot-and-frame parsing again. Search one table for the input, and give a corresponding entry from another table.

Understanding requires intelligence. Consider a dialogue between two people. John walks into his local pub one evening. At the bar he observes his friend Martin and so he walks up to him. Following the ordering of a drink John turns to Martin. 

John:   Evening Martin!

Martin: Hello John. Alright?

John:   A bit tired.

Martin: A hard day at work?

John:   No my mother went into hospital last night.

Martin: Nothing serious I hope?

John:   A stroke.

Martin: I'm sorry.

John:   That's okay. It's not your fault. Still, did you see the football last
        night?

Martin: Who was playing?
And so it continues. If we look at the intercourse that took place we will learn quite a lot about "understanding". The exchange starts with "Evening Martin". Martin recognises this as a common phrase, and responds with one of the possible standard responses. Perhaps John looks tired, or may be Martin is just being polite, but he asks after John's health and well being. John knows that the interrogation, "alright?" does not require an indepth reply. He knows this because of the circumstances of the intercourse taking place. If he was talking to his doctor, in a consultation he might give an in-depth reply. But in this circumstance he gives a short answer. Martin's response to John's answer, "a bit tired", is again a standard response to a common phrase. He doesn't care if he gets an answer or not. The reply that John's mother has gone into hospital generates an intelligent response from Martin. Martin understands the phrase, and has been taught that;
  1. Mother's give pleasure.
  2. People go into hospital if they are sick.
  3. Being sick is not pleasant, it is suffering.
  4. Someone who gives pleasure suffering passes on suffering to the person to whom they give pleasure. Therefore, by John's mother going into hospital John is also suffering.

Martin's intelligent response is none-the-less a standard phrase for these circumstances. However, it is selected because it is appropriate for the circumstances. John is taking a passive role in the conversation. He answers Martin's questions simply and honestly. He knows from experience that a stroke is a serious ailment. He knows that the common phrase "nothing serious I hope?" Requires different answers. If the ailment is not serious, then a simple "no", perhaps with qualification is required. If the condition is serious, then the condition itself is described. Martin, upon receiving the answer "stroke" remembers what was being talked about. That John's mother had gone into hospital, and therefore deduced that "stroke" applied to her condition. Martin has been taught that a stroke is a dangerous ailment, and replies with a standard phrase expressing emotion that he hopes will help John. Why does Martin wish to help John? Perhaps because if John is suffering then he, Martin, as a friend will also suffer. And suffering is not nice. John also replies with an intelligent response in the same vein to stop causing Martin any suffering. He may know that Martin enjoys watching football. Or he may deduce that as Martin is a male adult, and that male adults enjoy watching football so does Martin.

Within this exchange we notice that the understanding process requires recalling to memory what has been learnt about a vast range of subjects in the past. We also notice prediction occurring. Both parties attempts to predict what the response will be if they supply supply certain stimuli. These stimuli being phrases. This prediction is based upon their memories of responses to phrases, and also what their own response would be. If Martin's mother has never gone into hospital with a stroke. If Martin has never known of anyone else ever going into hospital with a stroke, he can still make judgements based upon similar circumstances.

Currently available computers do not have the memory capacity, or the speed to retain sufficient facts and be able to cross reference them as the human mind does. With CD-ROMs the memory limitations may be overcome, the speed problem will remain I believe until optical circuitry is implemented, with light energy taking the place of DC current. In the meantime the talking computer is limited to responding without very much understanding.