Hofstadter, Dennett - The Mind's I

Prelude . . . Ant Fugue 176ACHILLES: -are going at once.CRAB: -coming right up!ANTEATER: That's an interesting thought, Achilles. But it's unlikely that anyone could drawsuch a picture in a convincing way.ACHILLES: That's too bad.TORTOISE: Perhaps you could answer this, Dr. Anteater. Does a signal, from its creationuntil its dissolution, always consist of the same set of ants?ANTEATER: As a matter of fact, the individuals in a signal sometimes break off and getreplaced by others of the same caste, if there are a few in the area. Most often, signals arriveat their disintegration points with nary an ant in common with their starting lineup.CRAB: I can see that the signals are constantly affecting the caste distn bution throughout thecolony, and are doing so in response to th internal needs of the colony-which in turn reflectthe external situation which the colony is faced with. Therefore the caste distribution as yousaid, Dr. Anteater, gets continually updated in a way which, ultimately reflects the outerworld.ACHILLES: But what about those intermediate levels of structure? Yo were saying that thecaste distribution should best be pictured not in terms of ants or signals, but in terms of teamswhose members were other teams, whose members were other teams, and so on until; youcome down to the ant level. And you said that that was the key to understanding how it waspossible to describe the caste distribution as encoding pieces of information about the world.ANTEATER: Yes, we are coming to all that. I prefer to give teams of a sufficiently highlevel the name of "symbols." Mind you, this sense of the word has some significantdifferences from the usual sense. My "symbols" are active subsystems of a complex system,and they are composed of lower-level active subsystems.... They are therefore quite differentfrom passive symbols, external to the system, such as letters of the alphabet or musical notes,which sit there immobile waiting for an active system to process them.ACHILLES: Oh, this is rather complicated, isn't it? I just had no idea that ant colonies hadsuch an abstract structure.ANTEATER: Yes, it's quite remarkable. But all these layers of structure are necessary for thestorage of the kinds of knowledge which enable an