Amelia Oliveira

RESUMO: Os intérpretes dos manuscritos de Leonardo da Vinci partilham dos mesmos sentimentos de espanto e de fascínio quando examinam sua contribuição para a ciência moderna. Podemos, contudo, perceber uma constante tentativa em prol de uma revisão histórica acerca do papel desempenhado por Leonardo. Observando a história dessas revisões, é possível detectar aspectos significativos das perspectivas históricas e historiográficas dos envolvidos nessa discussão. É o que pretendemos fazer neste trabalho, focando a controvérsia entre Duhem, por um lado, e Sarton, Koyré e Rossi, por outro. Ao fazer isso, buscamos discutir alguns traços que marcam a distinção entre uma historiografia mais antiga e a nova historiografia da ciência, tal como exposta por Thomas Kuhn. ABSTRACT: Interpreters of Leonardo da Vinci's manuscripts share the same feelings of astonishment and fascination when they examine his contribution to modern science. However, it is possible to perceive an ongoing attempt towards a historical revision of the role played by Leonardo. Observing the history of this ongoing revision, it is possible to detect significant aspects of the historical and historiographical perspectives of those involved in this discussion. This article deals with the controversy between Duhem's point of view, on the one hand, and the views of Sarton, Koyré, and Rossi on the other. It aims to show some features that distinguish an older historiography from the new historiography of science as presented by Thomas Kuhn.

This may possibly be the first work on Kuhn and Sarton despite the importance of the subject, since Sarton was one of the main representatives of the “old” historiography of science, essential to understanding Kuhn’s critical proposal of a “new historiography of science” and the “historiographic revolution”. The theme has not been explored up until now by Kuhn scholars perhaps due to the vastness of Sarton’s work and the inadequate resource of merely citing excerpts out of context. Seeking to circumvent these problems, in a Koyréan way, we focus here on a case study. It is a peculiar case study and convenient for our purposes because, while it is of great importance for Sarton’s conception regarding the history of science and is in fact present throughout his academic career, it is not very extensive and can therefore be addressed in a more complete manner. We refer to Sarton’s treatment of Leonardo da Vinci and a discovery that he did not make: the discovery of blood circulation in the seventeenth century, attributed to William Harvey. Although Kuhn did not write about Leonardo or Harvey, we aim to show that he clearly positioned himself contrary to Sarton, albeit indirectly, with respect to this particular historical episode, as well.

A portion of the dietary nutrients is excreted due to the presence of antinutritional factors in some ingredients. This study aimed to determine the total and ileal digestibility coefficients of crude protein, as well as the passage rate of diets with different chemical compositions, supplemented or not with an enzymatic complex, in broiler chickens. No effect of the enzymatic complex was observed on the crude protein digestibility coefficient (P>0.05). However, the ileal digestibility coefficients of crude protein showed significant differences (P<0.05) within each group (with or without enzyme supplementation). The control treatment with the enzymatic complex presented a lower ileal digestibility coefficient of crude protein (P<0.05) compared to the control treatment without supplementation. The passage rate did not differ between treatments (P>0.05). It was concluded that the inclusion of the enzymatic complex, composed of calcium carbonate, Yucca extract, protease, phytase, and cellulase, in vegetable-based diets for broiler chickens did not affect digestibility coefficients or passage rate. Keywords: poultry farming, enzyme additives, nutrition, crude protein

Depois dos anos 60, e especialmente depois da repercussão da obra kunhiana, tornou-se comum a distinção entre o ponto de vista continuísta e o descontinuísta na avaliação do desenvolvimento científico. Kuhn passou a ser visto como o grande descontinuísta ao lado de Koyré e Butterfield e foi considerado o causador de uma grande mudança no modo de se conceber o desenvolvimento da ciência. Em diversas abordagens, a noção de continuidade tem sido, muito frequentemente, equiparada à acumulação, que implica necessariamente a negação da existência de revoluções científicas. Neste trabalho, buscamos mostrar que o emprego dos adjetivos “cumulativista” ou “continuísta” em oposição ao termo “descontinuísta” pode tanto suscitar interpretações equivocadas de visões históricas quanto estabelecer aproximações entre visões bastante distintas. Isso parece claro quando se analisa, por exemplo, as concepções de Sarton, Conant e Kuhn sobre a acumulação, tarefa a que nos propomos. A análise propicia considerações sobre os papeis desses pensadores na história da ciência.

What is the contribution of Duhem’s work to the modern historiography? His interpreters have been discussing this question and ordinarily have recognized that the main aspect in his extensive work is connected with his research of medieval science. It has become customary to speak of the “discovery of medieval science” as his foremost historiographic achievement. This paper aims to discuss some aspects of Duhem’s historiography more for its promotion of a new historical perspective than for its results. Duhem’s legacy for modern historiography can be investigated from the characteristics that mark this new perspective, as regarded by Thomas Kuhn.

The scientific work of Leonardo da Vinci may have served as the main inspiration for the historical research of George Sarton. Although he never produced a work he felt was worthy of its subject, the little that he did write about Leonardo reveals the importance he attributed to him in the history of science. This is especially clear in Sarton´s treatment of Leonardo and a discovery he did not make: William Harvey´s discovery of blood circulation in the 17th Century. In this article, we refer to this particular episode to trace Sarton´s conception of the development of science. It is a conception that illustrates well the traditional historiographic perspective that is the target of Thomas Kuhn´s criticisms. Although Kuhn never wrote about Leonardo or Harvey, we aim to show that he clearly positioned himself contrary to Sarton, albeit indirectly, with respect to this particular historical episode, as well.