Ruy J. Henríquez Garrido

The clinical empiricism of Thomas Sydenham (1624–1689) and his definition of especie morbosae represented a substantial turn in the medicine of his time. This turn supposed the shift towards an ontological conception of diseases, from a qualitative to quantitative interpretation. Sydenham’s clinical proposal had a great influence on empiricism philosophical thinking, particularly in John Locke and his delimitation of knowledge. The dialogue between medicine and philosophy, set out by Sydenham-Locke, reactivates the problem of the clinical and theoretical foundations of medical thought, as well as the limits of scientific knowledge. Similar to problem exposed in the Hippocratic treatise On ancient medicine, seventeenth-century medicine seeks its epistemological foundations and the solution to its difficulties in clinical experience, probability and analogy. The aim of this work is to show the Sydenham’s contribution to one of the great controversies between medicine and philosophy.

According to Girolamo Fracastoro in his book De contagione, et eorum et contagiosis morbis curatione (1546), contagious diseases are caused by the analogies between the seminaria contagionum (seedlets of contagion) and organisms affected by them. Such analogies are governed by the laws of sympathy and antipathy that regulate the universal order of things, according to the Neo-Platonic philosophy of the Renaissance, whose influence was decisive in the discourse of the physician of the Verona. The purpose of this paper is to investigate the sources and possible reasons that led Fracastoro to support an idea that, due to its apparent qualitative nature, would contradict its rejection to the hidden qualities in explaining the etiology of contagion.

Thanks to how Girolamo Fracastoro defines the different types of contagion in his book De contagione, et contagiosis morbis et eorum curatione, libri tres (1546), and his defense of the “seeds of contagion” (seedbed) as the cause of contagious diseases, he is considered today one parent of the modern epidemiology and microbiology. One of the crucial problems in this book is to explain the remote transmission of the contagious diseases refuting the etiologic use of the occult qualities. The aim of this study is to investigate the philosophical background of the problem and draw the conclusions that his solution had for medicine and for science in general.

The conception of contagious disease that Girolamo Fracastoro provides in his work De contagione et contagiosis morbis, marks the origin of modern epidemiology and microbiology. This conception puts into play the Galenic and Aristotelian traditions of research, faced with its own conceptual limitations of the growing mechanistic thought of the time. According to Fracastoro, epidemic diseases spread by invisible living germs called seminaria, begotten by corrupted humours. Fracastoro resorted to the old notions of "sympathy" and "antipathy" to respond to questions about how seminaria is transmitted from one body to another, and what is the specificity that limits its transmission to certain species and organs. Like Galileo and Descartes, Fracastoro tries to establish a dialogue in the field of medicine between the Aristotelian vitalism and the modern mechanistic perspective. The purpose of this paper is to highlight the ideological, theoretical and conceptual assumptions, both philosophical and scientific, assumed by Fracastoro with regard to the problem of contagion.

The analysis of the Rules for the Direction of the Mind reveals not only the early interest that Descartes had in the mind and its relationship with the body. It also proves that his idea about the mental aspect is an integral part of Descartes’ general program for the basic principle of Science. On the other hand, it demonstrates that the Cartesian’s thought regarding the mind could not be understood without the critique of the Aristotelian-scholastic epistemological paradigm that is expressed in this trascendental work