送交者: insight 于 2006-2-08, 20:24:17:
Consciousness and the top-down/bottom-up models
1) The top-down model works on the principle that the answer to a problem is deterministic and there is a finite-step algorithm to reach that answer if we start from certain known premises or initial conditions. However, as implied by the Godel’s incompleteness theorem, if we start with finite knowledge, then we end up with finite knowable predictions. Due to the deterministic nature of these calculations, nothing new can be generated. This lead to the conclusion that artificial processes based on the top-down model, such as all man-made machines including computers, can not generate anything new and innovative. The conclusion also be extended to human organizations, and societies, where authoritarian rule always suppresses creativity and innovation. Certain human mental abnormalities, such autism, exhibits characteristics of such a model. In fact, it is found that autistic persons tend to think in pictures and are weak in languages and social interaction. This can be interpreted as the autistic brain working better in mechanical processes of patterns than generating abstract conceptions, or to put it another way, it only sees trees but not woods.
2) The bottom-up model is based on the idea that nothing is pre-designed and programmed using any finite-step algorithm and the outcome of the bottom-up process can be non-deterministic. Therefore this model is not restricted by the Godel’s theorem in that it can freely generate novel conjectures and intuitions. That is to say, it can generate new knowledge with finite known knowledge, with the help of a formal language.
3) What is the relationship between consciousness and the two models? Consciousness is a process of self-awareness, which is based on the understanding of patterns, not just plainly seeing them. Understanding, in turn, involves the construction of mental models by the use of abstract symbols such as languages, which we may call conjectures and intuition leaps. Undoubtedly, such processes have to be based on the bottom-up model as discussed above. Therefore consciousness is a bottom-up process. Furthermore, we can observe that the bottom-up model not only facilitates the evolution of human intelligence and culture, but also the evolution of lives on earth in general.