More than just an elegant graph of the ALICE brain, these spiral images
outline a territory of language that has been effectively "conquered" by ALICE and AIML. No other theory of natural language processing can better explain or reproduce the results within our territory. You don't need a complex theory of learning, neural nets, or cognitive models to explain how to chat within the
limits of ALICE's 25,000 categories. Our stimulus-response model is as good a theory as any other for these cases, and certainly the simplest.
If there is any room left for "higher" natural language theories, it lies outside the map of the ALICE brain. Academics are fond of concocting riddles and linguistic paradoxes that supposedly show how difficult the natural language problem is. "John saw the mountains flying over Zurich" or "Fruit flies like a banana" reveal the ambiguity of language and the limits of an ALICE-style approach (though not these particular examples, of course, ALICE already knows about them).
In the years to come we will only advance the frontier further. The basic outline of the spiral graph may look much the same, for we have found all of the "big trees" from "A *" to "YOUR *". These trees may become bigger, but unless language itself changes we won't find any more big trees (except of course in foreign languages).
The work of those seeking to explain natural language in terms of something more complex than stimulus response will take place beyond our frontier, increasingly in the hinterlands occupied by only the rarest forms of language.
Our territory of language already contains the highest population of sentences that people use. Expanding the borders even more we will continue to absorb the stragglers outside, until the very last human critic cannot think of one sentence to "fool" ALICE.