Portrait of Girolamo Fracastoro by Titian, c.a. 1528. National Gallery, London. Open Domain

Girolamo Fracastoro's On the Sympathy and Antipathy of Things 

by Enrico Piergiacomi 

June 1, 2024

Enrico Piergiacomi offers the first published English translation of the proem to Girolamo Fracastoro's On the Sympathy and Antipathy of Things, a text which supplies one of the earliest extended treatments of the epistemological and physical foundations of contagion.

Enrico Piergiacomi is an assistant professor at the Technion - Israel Institute of Technology. He specializes in ancient/modern philosophical thought and its intersections with science, medicine, theology, and ethics.

The philosopher-poet Girolamo Fracastoro (1478-1553) is perhaps most renowned for his scientific poem On the French Disease [De morbo gallico] (1530), in which he provided a detailed exposition of the origin, etiology, and therapy of syphilis. Over a decade later (1546), Fracastoro revisited the topic, and revised this poem, within the three books of his work On Contagions [De contagionibus], which provided one of the first extended treatments of contagious diseases and categorized many of them, including elephantiasis, leprosy, phthisis, rabies, and typhus, based on their species, causes, modes of transmission, and treatments. 

At the same time as he published On Contagions, Fracastoro also wrote another, lesser known, work called On the Sympathy and Antipathy of Things [De sympathia et antipathia rerum], which he dedicated to the Italian cardinal Alessandro Farnese (1520-1589), to secure his patronage. This less famous text paid greater attention to the epistemological and physical foundations of the medical theory of contagion, which Fracastoro argued could be explained by how the attraction of similar elements (sympathy) and repulsion of dissimilar one (antipathy) can influence the activities of the organism (growth, sensation, thought), and by how pathogens, which he called fomites, or "sparks," move through air and other media. Interest in contagion traces back to various historical sources, including mentions in Thucydides, Lucretius’ brief, yet seminal, exploration in Book 6 of On the Nature of Things, Hellenistic practitioners (such as Asclepiades or the Methodists), Plutarch, the pseudo-Aristotelian Problems, and Galen’s treatises, particularly On the Initial Cause and On the Different Kinds of Fever. Renaissance contemporaries of Fracastoro, like Giovanni Battista da Monte, Marsilio Ficino, and Filippo Beroaldo also addressed the topic, especially within their commentaries on ancient authors. Still, none of these earlier works demonstrated the same depth and systematic approach as Fracastoro’s On the Sympathy and Antipathy of Things

De sympathia et antipathia rerum liber unus. De contagione et contagiosis morbis et curatione libri III. Girolamo Fraastoro, First Edition, Sophia Rare Books

Fracastoro’s text grounds both the etiology and therapy of contagious diseases in a meticulous account of nature or of the natural processes, while attempting to refute two prevalent anti-scientific Renaissance explanations of contagion: the astrological origins of disease and the belief in “occult powers” in poisons/infections. Ultimately, however, Fracastoro places his investigation of the On the Sympathy and Antipathy of Things in a “middle space,” endeavoring to study the causes of nature and disease that are neither too general, which might satisfy those content with either abstract explanations or occult causes, nor too minute or specific, which might be comprehensible only to God. He deliberately distances himself from both the Renaissance notion of magic and the dogmatic philosophy of nature that claims to comprehend every single element involved in the origin of diseases.

When paired with Fracastoro’s earlier poem, On the French Disease, which aimed to convey the theory of contagion through poetry, On the Sympathy and Antipathy of Things holds the potential to sensitize contemporary readers to a crucial and pressing issue: the necessity of disseminating scientific knowledge among non-scientific audiences in a manner that is both elegant and rigorous.

The translated extract provided here consists of the work’s proem.

[Note: the numerical division of causes is the author’s own.]

"From Girolamo Fracastoro to the most distinguished Alessandro Farnese, Cardinal of Verona: greetings..."

Portrait of Cardinal Alessandro Farnese by Titian. National Museum of Capodimonte, Q 133, Wikimedia Commons

"...Since man is born for man, most noble prince, I observe that it has been often debated which benefit is more advantageous: whether the one attained through leisure by contemplating and writing or the one achieved through activities and accomplishing remarkable deeds. Indeed, many have significantly benefitted not only for their relatives and friends but also for the public good and many nations by engaging earnestly in actions, while many others have done so through writing.

(…) However, both modes of benefiting can be performed by very few individuals whom God especially favored, as it has always been allowed that leisure and activities tend to oppose each other. This is why kings and princes – who, preoccupied and distracted by actions, can indulge less in leisure – have been accustomed to benefiting more from the first mode (i.e., through activity) and less from the other mode (i.e., through things produced during leisure). But indeed, those who are true kings and princes take care and foresee that what they cannot achieve by themselves should be provided through others. As a result, while they may excel in the first aspect, they may not appear to lack in the second for the benefit of humanity, for whose sake they are born and appointed by God. (…) It follows that greater is the glory of those few, whom true virtue was able to elevate to the point of imitating the best gods. Among them (allow me to come to you, most excellent young man), you certainly shine with an evident, unspeakable blaze of virtues, and you seem to be particularly bound by [that form of piety] which seeks and desires to benefit both itself and others.

(…) What is also extremely admirable in this matter is that, despite the weight and diversity of such responsibilities, you – not forgetful of literature – do not neglect to study and contribute your efforts in this field, not only for yourself but also for others. Indeed, being born with such great and excellent nature, equally fit for both actions and the pursuit of literary studies, you undoubtedly ensure that much may be expected from you in the future. In the meantime, what you cannot fulfil due to your age and the most important duties, others can certainly complete. You embrace and support the latter with such goodwill, you support and incite them with all your zeal, generosity, and patronage, that they owe no less to your dedication to literature than to Christian liberty. In fact, I myself can bear witness to this, as you have never seen me asking for anything from you, yet you have pursued and supported me with not a few benefits for this very reason, and you will continue in the days that will come. This is why my dedication and attachment to your benevolence and virtue are so deep that, for a long time, I have had nothing in my mind so firmly fixed as the thought of doing something for you and your devotion that could be called accomplished for your sake. This was the only way I could show how grateful my soul is towards you. Although I have been delayed by various engagements from completing this matter as soon as I would have wished, I have now finally finished it – not in the field that you would have desired, and which I thought would have made you happier, but in a topic that, I hope, will not be unappreciated by you because it will bring some considerable benefit.

"The Blind Leading the Blind" by Pieter Breugel the Elder (1568), Museu de Capodimonte, Naples, Public Domain

"Therefore, it seemed appropriate to me to write about contagion, all contagious diseases, and their treatment during the leisure time you granted to me,  which means that this work is yours..."

Indeed, it is a vast subject full of not insignificant marvels, to which I have added a no less needed (in my opinion) commentary on the consensus and dissension of things, which are called sympathy and antipathy. Without it, it did not seem possible to thoroughly investigate and explain the nature of contagion. I gladly took on both topics, for if the latter [scil. the study of sympathy and antipathy] is worthy of knowledge, the former [scil. the analysis of the contagion] seems to contribute significantly to the well-being of mortals. Yet, very little on these matters has been passed down through the writings of our predecessors who have reached us and that I read.

Pauli Aeginetae medici insignis opus divinum: quo vir ille vastissimum totius artis oceanum, Laconica brevitate, sensibus argutis, merisque aphorismis in epitomen redegit. Basel: Andreas Cratander & Johannes Bebelius, 1532, The Le Roy Crummer Collection

It is said that Galen wrote something about the sympathy and antipathy of things, but those writings have either been lost or have yet to come to light in our times, as far as we know. As for contagion, Hippocrates appears to have touched the contagion while addressing the epidemics, but he mostly observed them rather than providing detailed explanations of their nature. It is true that Galen demonstrated something more after him: yet he, his followers such as Paul of Aegina and Aetius of Amida, and other ancient [doctors] neglected, in my opinion, much that could be significantly desired to study.

Conversely, more recent [doctors] do not appear to have said much more about contagion other than that it arises from some occult properties. No one has attempted to understand the general nature of contagions, what their principle is, how they originate, and why some leave fomites [scil. inanimate vectors of contagion] and some others propagate at a distance; why some diseases are more contagious, but less aggressive and milder, while others are less contagious, but more violent and severe; how contagion differs from poisons; and many other similar questions. These people seemed content to attribute all these causes to some hidden properties, as they call them, and thought it sufficient not only for themselves but also taught them to others.

Satisfied by these [properties], innumerable people have philosophized [on them], which is a practice that I have always considered unworthy of any philosophical person. For, among the causes, (1) some are most universal and remote from things, (2) others are closer and more particular, finally (3) some are very close and specific. Now, reaching the inherent and closest causes of hidden and difficult matters [3] is undoubtedly possible either to God or a divine [being]. To focus solely on the most universal causes [1] is the quality of a lazy and rustic mind. But finally, investigating the intermediate causes and striving towards the particular ones [2] (to the extent possible for a human being) is undoubtedly the trait of a philosopher.

Perhaps one may wonder why I have chosen to write on these two subjects, the first of which has been left nearly untouched by our predecessors, while everyone admits that the second is beyond human knowledge. In reality, I also concede that both the sympathy of things and the nature of contagion are difficult and challenging subjects: what is more, I believe that it would be even more foolish or arrogant for someone to attempt to investigate their closest and most specific causes [3]. Nevertheless, if the same person were to explore the intermediate causes [2], I do not doubt that he would discover many things that can delight and greatly benefit. This is precisely the goal I have set for myself in this investigation.

"However, I hope, however, that no one will be surprised that our predecessors did not fully explore the subject of contagion."

The Triumph of Death (1562)  by Pieter Bruegel the Elder, Museo del Prado, Madrid 

As it happens in all disciplines, not everything can be completed by their founders, since they tend to focus on universal aspects and the principles of things. Therefore, in the realm of natural philosophy, countless matters remain either untouched or not thoroughly examined. Until now, indeed, I do not recognize an adequate explanation of how thinking happens in us, nor that it has been sufficiently demonstrated what is the nature of the so-called spiritual qualities, and many other things. Similar reasoning is applied in the field of medicine, where many things remain to be explored, which our forefathers have left for future generations and descendants to investigate, and we, in turn, will leave for our descendants. Moreover, many of the writings that have been produced are lost, and many still exist, but not all can access them. Such is the condition and vicissitudes of mortal affairs.


Readers of my work will be able to judge for themselves whether or not is really necessary the investigation of contagions, which I am currently undertaking, is really necessary – if the gods permit it. Whatever these matters may be, which I address according to ancient tradition to the esteemed prince, please receive them with a willing mind, also because of your own status and accomplishments. Furthermore, with your great influence, please protect them so that no one will dare to attack with baseless accusations what has been approved by you and published under your auspices.


Latin text (1555). Hieronymi Fracastorii Veronensis Opera omnia in unum proxime post illius mortem collecta, quorum nomina sequens pagina plenius indicat.

Italian translation. Pennuto, Concetta. 2008. De sympathia et antipathia rerum, Liber I: edizione critica, traduzione e commento, Studi e Testi del Rinascimento Europeo, 31, Rome, Edizione di Storia e Letteratura.

Additional Resources:

Holmes, Brooke. (forthcoming) Sympathy and the Tissue of the World: Life, Community, and Nature in the Ancient Mediterranean.

Nutton, Vivian. 1983. "The Seeds of Disease: an Explanation of Contagion and Infection from the Greeks to the Renaissance," Medical History 27: 1–34. 

Pastore, Alessandro and Enrico Peruzzi, eds. 2006. Girolamo Fracastoro fra medicina, filosofia e scienze della natura, Firenze: Olschki.

Pennuto, Concetta. 2008. Simpatia, fantasia e contagio: il pensiero medico e il pensiero filosofico di Girolamo Fracastoro, Rome: Storia e Letteratura.

Singer, Charles and Dorothea Singer. 1917. "The Scientific Position of Girolamo Fracastoro, with Especial [sic] Reference to the Source, Character and Influence of His Theory of Infection," Annals of Medical History 1.1: 1-34.