Do nascimendo da Ciência

Carlo Rovelli é o Carl Sagan do século XXI. Nenhum outro divulgador de ciência consegue fazer o que ambos fazem: relatar informação científica impregnada de emocionalidade. É preciso uma paixão imensa pelo que se faz e se quer expressar para chegar aqui, e do muito que tenho lido Sagan e Rovelli são inigualáveis.

Dito isto, este livro foi uma das suas primeiras incursões na escrita de divulgação científica, mas é um trabalho apaixonante pelo modo como Rovelli procura a origem da ciência, discutindo o nascimento da atual civilização centrado no momento em que a sociedade grega conseguiu iniciar a separação entre o misticismo e o materialismo. Nesse sentido, julgo que o autor e editora erraram ao destacar Anaximandro no título, fazendo parecer que estamos perante um livro sobre a vida do cientista —que apesar de aqui descrito como primeiro cientista está longe de ser uma figura marcante da ciência — quando na verdade estamos perante um livro que discute o nascimento da ciência, como muito bem enfatiza o subtítulo da tradução portuguesa.

Quando comecei a ler senti desde logo algum afastamento de Anaximandro, as suas ideias são interessantes, mas longe de ser estimulantes, ou até mesmo corretas, ainda que como Rovelli diz, tenham sido precursoras de muito do que viemos a descobrir depois. Mas o livro ganha verdadeiramente asas quando Rovelli termina o descritivo sobre as ideias de Anaximandro e inicia a discussão sobre a cronologia, sobre a relação de Anaximandro com o início do pensamento científico na Antiga Grécia. Antes de Anaximandro temos apenas Tales, mas que juntamente com Anaxímenes, todos da cidade de Mileto, definiriam a chamada Escola Milesiana, sendo mais tarde referenciados por Aristóteles como os “filósofos da natureza”.

Estes filósofos/cientistas pré-socráticos são mais importantes pelo modo como quebraram com milénios de um discurso assente no medo do desconhecido construtor de teorias excêntricas repletas de figuras mágicas. Por isso mesmo, nessa segunda parte do livro, Rovelli acaba centrando toda a discussão na definição daquilo que é a ciência, dando resposta ao subtítulo da edição italiana “Che cos’è la scienza”. Para ilustrar essa discussão deixo um excelente excerto do início dessa discussão:

“What is scientific thinking? What are its limits? What is the reason for its strength? What does it really teach us? What are its characteristics, and how does it compare with other forms of knowledge?”

(…)

“In the nineteenth century, a common joke was that Isaac Newton had not only been one of the most intelligent men in human history, but also the luckiest, because there is only one collection of fundamental natural laws, and Newton had had the good fortune to be the one to discover them. Today we can’t help but smile at this notion, because it reveals a serious epistemological error on the part of nineteenth-century thinkers: the idea that good scientific theories are definitive and remain valid until the end of time.”

“The twentieth century swept away this facile illusion. Highly accurate experiments showed that Newton’s theory is mistaken in a very precise sense. The planet Mercury, for example, does not move following Newtonian laws. Albert Einstein, Werner Heisenberg, and their colleagues discovered a new collection of fundamental laws—general relativity and quantum mechanics—that replace Newton’s laws and work well in the domains where Newton’s theory breaks down, such as accounting for Mercury’s orbit, or the behavior of electrons in atoms.”

“Once burned, twice shy: few people today believe that we now possess definitive scientific laws. It is generally expected that one day Einstein’s and Heisenberg’s laws will show their limits as well, and will be replaced by better ones. In fact, the limits of Einstein’s and Heisenberg’s theories are already emerging. There are subtle incompatibilities between Einstein’s theory and Heisenberg’s, which make it unreasonable to suppose that we have identified the final, definitive laws of the universe. As a result, research goes on.”

(…)

“these discoveries confirmed the cognitive strength of science. Like Newton’s and Maxwell’s theories in their day, these discoveries led quickly to an astonishing development of new technologies that once again radically changed human society. The insights of Faraday and Maxwell brought about radio and communications technology. Einstein’s and Heisenberg’s led to computers, information technology, atomic energy, and countless other technological advances that have changed our lives.”

(…)

Newton’s theory is not less valuable after Einstein. Anyone who needs to calculate the force of wind on a bridge can use either Newton’s theory or Einstein’s. The difference in results will be exceedingly small and utterly irrelevant for the practical issue of constructing a bridge that will not collapse. Newton’s theory, then, is perfectly adequate to this problem and gives us fully trustworthy results (and ones much simpler to use).

Theories have domains of validity determined by the precision with which we observe the world and by the regimes in which the observed phenomena are situated.

(…)

Is the world as Newton describes it, or Einstein, or neither? If neither, is there anything we know about the world? If all we can say is that certain equations are useful for calculating certain physical phenomena within certain margins of error, then we do not leave science any capacity to help us understand the world. Despite our scientific knowledge, the world remains utterly incomprehensible.

The problem with such a reduction of science to verifiable results is that it fails to do justice to the practice of science, the way it actually grows, and above all to the actual use that we make of it, which is the reason why science ultimately interests us. I explain with an example.

(…)

“Science cannot be reduced to quantitative predictions. It cannot be reduced to calculation techniques, operational protocols, or the hypothesis-deduction method. These are tools, razor sharp and of fundamental importance. They offer relative guarantees, clarity, means for dodging errors, techniques for unmasking mistaken assumptions. But they are only tools and only some of the tools in play in scientific activity. They are at the service of an intellectual activity whose substance is something else.”

(…)

“The confusion between science as a cognitive activity and science as a producer of testable predictions leaves science open to the critique of the dominion of technology.”

(…)

“In light of these considerations, what is scientific knowledge? The explicit goal of scientific research is not to make correct quantitative predictions; it is to understand how the world works. What does this mean? It means building and developing an image of the world, which is to say a conceptual structure for thinking about the world, effective and consistent with what we know and learn about the world itself.”

(…)

“Science is looking further, with the awareness that our ideas often prove inadequate the moment we step outside our own little corner of the world. Above all, it is unmasking prejudices, and building and developing novel conceptual tools with which to think more effectively about the world.

Scientific knowledge is the process of continuously modifying and improving our conception of the world, selectively and constantly questioning the assumptions and beliefs on which it is based, searching for modifications that prove to be more effective.

Scientific thinking explores and reshapes the world. It offers us new images of the world. It teaches us how and in what terms to think about it. Science is a continuous quest for the best way to think about and look upon the world. It is, above all, an ongoing exploration of new forms of thinking.”

(…)

“This adventure is grounded on the entirety of accumulated knowledge, but its soul is perpetual change. The essence of scientific knowledge is the capacity to avoid clinging to certainties and received worldviews, and instead be prepared to change these, repeatedly if need be, in light of our knowledge, observations, discussions, different ideas, and criticisms. The nature of scientific thought is critical and rebellious. It does not suffer a priori conclusions, reverence, or untouchable truths.”