a formiga de langton


Quem monta o Lego ?!

A caminhada, dos sistemas hierárquicos para os sistemas distríbuidos, em paralelo com a de um "olhar" reducionista TOP-DOWN para um outro oposto, BOTTOM-UP, tem-se vindo a verificar recentemente um pouco por todos os ramos da ciência, sobretudo nas ciências da computação (sendo particularmente evidente na Computação Bio-Inspirada). A "ruptura" tornou-se particularmente evidente, após a introdução em meados da década de 60, inicio da década de 70, por Langton, entre outros, da área de Vida Artificial (segue um livro de divulgação possível, entre tantos outros). Paradígmas computacionais como a Computação Evolutiva (Algoritmos Genéticos, Estratégias de Evolução, etc) deram o mote (antes mesmo das Redes Neuronais Artificiais RNA, terem provado conseguir mapear a simples função lógica XOR !), mas seguiram-se em força as próprias RNA (a partir de 1986 com os trabalhos de Rumelhart provando que com o perceptrão seria finalmente possível mapear XOR), os Autómatos Celulares, as Redes Celulares, bem como mais recentemente a Computação Granular, os Sistemas Imunes Artificiais, os algoritmos Meméticos, a Inteligência de Enxame, entre outros pertinentes exemplos (ver links e refs. de post anteriores). Tal como sugerido por Langton, o conceito fundamental da Vida Artificial é o do comportamento emergente; [...] Natural life emerges out of the organised interactions of a great number of nonliving molecules, with no global controller responsible for the behaviour of every part. Rather, every part is a behaviour itself, and life is the behaviour that emerges from out of all of the local interactions among individual behaviours. It is this bottom-up, distributed local determination that aLife employs in its primary methodological approach to the generation of lifelike behaviours [...]. Apesar do pioneirismo de cerca de 30-35 anos, é contudo num livro do ano transacto que podemos encontrar uma das mais sintéticas e notáveis passagens, descrevendo o novo "olhar", quer pela sua simplicidade e beleza, quer pela sua grandeza em perspectiva e rigor histórico. Segue então assim:

[...] Have you haver seen a child take apart a favorite toy? Did you then see the little one cry after realizing he could not pull all the pieces back together again? Well, here is a secret that never makes the headlines: We have taken apart the universe and have no idea how to put it back together. After spending trillions of research dollars to disassemble nature in the last century, we are just now acknowledging that we have no clue how to continue - except to take it apart further. Reductionism was the driving force behind much of the twentieth century's scientific research. To comprehend nature, it tell us, we first must decipher its components. The assumption is that once we understand the parts, it will be easy to grasp the whole (seria assim se o mundo real fosse linear em comportamento !). Divide and conquer; the devil is in the details. Therefore, for decades we have been forced to see the world through its constituents. We have been trained to study atoms and superstrings to understand the universe; molecules to comprehend life; individual genes to understand complex human behavior; prophets to see the origins of fads and religions. Now we are close to knowing just about everything there is to know about the pieces. But we are as far as we have ever been from understanding nature as a whole. Indeed, the reassembly turned out to be much harder than scientists anticipated. The reason is simple: Riding reductionism, we run into the hard wall of complexity. We have learned that nature is not a well-designed puzzle with only one way to put it back together. In complex systems the components can fit in so many different ways that it would take billions of years for us to try them all. Yet nature assembles the pieces with a grace and precision honed over millions of years. It does so by exploiting the all-encompassing laws of self-organization, whose roots are still largely a mystery to us. Today we increasingly recognize that nothing happens in isolation. Most events and phenomena are connected, caused by, and interacting with a huge number of other pieces of a complex universal puzzle. We have come to see that we live in a small world, where everything is linked to everything else. We are witnessing a revolution in the making as scientists from all different disciplines discover that complexity has a strict architecture [...].

As palavras são de Albert-László Barabási, em "Linked", Perseus Publishing 2002. Resta saber portanto, quem monta o Lego e como ?! Mas pistas por aqui não faltam, apesar do caminho ser árduo. E ás vezes, passando uma só hora a brincar com um bébé, ganha-se um dia inteiro de laboratório !
posted by AntColony @ 2:14 AM