The texts by Paracelsus, Felix Platter and Thomas Willis under consideration here have two things in common, despite their separate historical and cultural settings. First, they describe people who seem to relate both to their own world and to the external world in problematical ways which the authors variously call stultitia, fatuitas or stupiditas: “foolishness”. My translation is intentionally imprecise and will, I hope, restrain the reader from jumping to the conclusion that it signifies any clinical concept recognizable in modern medicine; it is, rather, an algebraic x whose content needs further investigation. The second common factor is that these are precisely the texts which some commentators do indeed believe to contain “early” diagnoses of a modern concept of intellectual disability (“mental retardation”, “learning disability” etc.). This belief, of axiomatic status, presupposes that some such concept has existed across different historical periods in a more or less mutually recognizable form, and therefore that “foolishness”, in the medical writers discussed here, just is, if primitively, our “intellectual disability”. However “foolishness” needs closer examination, which I attempt to provide here.

The discoveries in the late nineteenth century that malaria is caused by protozoan parasites, which are transmitted by mosquitoes, quickly led to intense speculation about its history in antiquity. The historiography of malaria has passed through three distinct phases during the last hundred years or so. The first generation of historians to consider the effects of malaria did exaggerate its significance in some respects. The argument by W H S Jones that the Greek doctrine of fevers was based on malaria was generally and rightly accepted. However, it is not surprising that his view that malaria was a major reason for the degeneration of the moral character of the ancient Greeks attracted little sympathy. The eradication of malaria from southern Europe in the 1930s and 1940s contributed to a decline of interest in the subject. Subsequently medical historians and even professional malariologists tended to minimize the historical significance of malaria. The revisionist tendencies of this second phase of research led to attempts to reassess some of the details of the evidence upon which Jones had relied. For example, Leonard Bruce-Chwatt and Julian de Zulueta rejected Jones's belief that Plasmodium falciparum, the most dangerous of the four species of human malaria, was already active in Greece in the fifth century BC. They suggested that it started to spread in southern Europe only during the time of the Roman Empire and attributed all the references to intermittent tertian fevers in Hippocratic texts dating to the fifth and fourth centuries BC to the less virulent P. vivax. Although the literature produced during this second phase of scholarship was in many ways more sophisticated, it still suffered from some of the same weaknesses; in particular, analysis proceeded in a purely qualitative manner, without any consideration of the effects of malaria on historical human populations in quantitative terms. A second weakness was a tendency to make generalizations covering the whole of Mediterranean Europe. Since many types of mosquito are incapable of transmitting malaria to humans, mosquito breeding sites do not occur everywhere, and many mosquitoes do not fly further than a few hundred yards from their breeding sites, malaria can only be really understood by micro-analyses, conducted at a very local level, of geography, hydrology, climate, competition between different species of mosquito for breeding sites, and human activities.

Hospitals in Germany had traditionally provided care on a voluntary basis. Before the end of the nineteenth century, hospitalization was compulsory only during epidemics or in the case of infectious diseases such as syphilis or leprosy. Voluntary hospitalization normally occurred only when hospital beds were available, when payment was guaranteed, or during emergencies. Towards the end of the nineteenth century, however, there was a definite increase in hospitalization levels, primarily due to two important developments: the introduction of health insurance in 1883, and the growing number and size of hospitals. Health insurance covered its members' hospital expenses, and the hospitals provided facilities for more and more patients.

The link between science, medicine and public trust has been much discussed. Surgery shared in the public confidence in the efficacy of scientific medicine and the good intentions of its practitioners. This does not seem to have been directly linked to evidence of either. Harry Marks has argued that drug manufacturers were not included in the trust accorded to medical practitioners. Regulations and restrictions on the introduction of new drugs in America from the late 1930s were linked to widespread suspicion of commercial motives. The motives of surgeons were not suspected in the same way, and surgery in the 1930s was not subjected to the same tests of safety (or efficacy) that were beginning to be applied to drugs. Surgeons were free to adopt, adapt, or invent any surgical procedure as they saw fit. Was their surgery based on what Marks has called “the vagaries of clinical opinion”, and Christopher Lawrence the “incommunicable knowledge” behind clinical judgment? Or were surgeon citizens of “the republic of science”, basing their practice on what was considered at the time to be acceptable evidence?