The claim that there are medical descriptions of intellectual disability this early involves assumptions about its defining characteristics, and the definition needs to be spelled out if we are to establish the degree of connection or disconnection between intellectual disability and the “foolishness” mentioned in these historical texts. Intellectual disability is perceived by cognitive, developmental and educational psychologists and in much everyday thinking as follows: (1) It is a deficit in the “intelligence” specific to humans, defined more or less as an (in)ability to think abstractly. (2) This deficit occurs in the mind, as a natural realm distinct from the body; in this sense it differs from physical or sensory disability. (3) The deficit is incurable and thus defines the person, from birth or an early childhood onset until death; in this sense it differs from mental illness. (4) The people thus identified are a tiny, abnormal minority at the lowest extreme from the norm of intelligence. (This holds true whether or not the norm is measurable, by IQ for example.) (5) The causes of the deficit are natural in a deterministic sense, i.e. “nature” implies “necessity”. (This holds true whether or not nurture is perceived to have an influence.)

All the foregoing constituents post-date the early modern period, and so there is a problem with assuming that early modern foolishness is the precursor of our intellectual disability. The idea of an intelligence peculiar to the human species, separate from intelligences such as God or the angels, arrived only after logic-based methods started to be used to define essences of species, i.e. with the birth of modern biological classification in the eighteenth century. An ability for abstract thinking was perceived as universally human only when political and ecclesiastical élites were challenged over their divine right to prescribe the abstract principles known as “common ideas” to the rest of the population, and individuals started getting ideas by themselves. The dualism of physical and intellectual disability is Cartesian and was firmly established only by John Locke; in its medical uses it succeeded a Galenist, organic model of psychopathology that still held firm into the seventeenth and eighteenth centuries. The intellectual unity of the person over time came only with the decline in models of personhood based on transience, such as temperament in medicine and providence in religion; incurability, a vital constituent, was finally established only a century ago. “Abnormal” was Francis Galton's late Victorian invention, eliding previous distinctions between the wholly unnatural and the merely unusual. “Nature versus nurture” was Galton's invention too, while the conflation of nature with necessity had taken hold only a little earlier, in phrenology for example.

Clearly this model could not have made sense to Paracelsus, Platter or Willis. And it would be naive to suppose that if their foolishness in its various forms is not identifiable with our intellectual disability, it is because they are mere primitives. What then did they have in mind?

For Cranefield and Federn, Paracelsus's De generatione stultorum (‘On the generation of fools’) is “one of the most remarkable documents” in the history of “mental deficiency”.⁴ Paracelsus opens by expressing his wonderment that “When God has redeemed man supremely and so dearly by his death and blood, he allows this same to be born an unwise man”. To understand this passage we should know something about his conception of human nature. Paracelsus's nature is not, as for us, one half of a bipartite schema, nature versus nurture. Like his contemporaries and predecessors he saw nature as a middle ground between nurture on the one hand and variants of pure determinism on the other. Human nature was not fixed but dynamic, a process of spiritual self-renewal.⁵ Determinism, by contrast, belonged with classical notions of necessity or fate, to which Christianity had added the divine will and providence, and to which some Christians, with mounting urgency in the sixteenth century, had added predestination. In his prologue, Paracelsus implicitly rejects the ultra-predestinarian notion of a God who before the Fall had already preordained some as elect, others as reprobate and bound for hell. He separates the natural aspect of foolishness from its necessary or divinely determined aspects in order to illustrate a principle of universality; whoever you are, foolishness is incurable in nature, but curable by divine intervention. Cure comes neither from earthly doctors (“medicine has nothing to do with it”) nor from the stars but is a matter for “philosophizing”, i.e. for speculative theology; it exists in a realm beyond time, beyond the mortal and merely human reason of the “animal body”.⁶ The universal possibility of redemption expresses God's even- handedness towards people who “cannot recognize or understand his name, his death, his law, his signs, his work, his goodness shown towards man”, and who surely cannot be predestined for hell if they are not responsible for their own ignorance.⁷

It seems to Adam's descendants that nature is necessity, in the astrological form of “hard zodiacal signs”.⁸ But it is necessity in appearance only. Astrology, in spite of its own claims, cannot know the underlying causes of human corruption because they lie within “hidden” regions of nature and only appear to us as necessity because of the Fall. Paracelsus personifies the natural forces of this occult realm as “Vulcans”, super-alchemists who forge each individual human. All we can know, he says, is that some Vulcans are more skilled than others, so that their varying degrees of incompetence or inexperience lead to varying degrees of foolishness in the individual.⁹ The production process, even to Paracelsus, who elsewhere talks so much about bringing the hidden to light, is not for humans to discover.

When Paracelsus says in his prologue that the possibility of redemption “is greatly to be wondered at” in the case of the unwise, one might think his wonderment to be that even some of the intellectually disabled are redeemable.¹⁰ However it could mean that we are all redeemable in spite of the fact that we are all fools, qua human. Paracelsus's fools here range across a spectrum that stretches from discrete groups to this universal humanity. It is important to focus on the specific characteristics of fools at each point in the text. “Inability to recognize or understand religion”, if not universal, would at least embrace the newly encountered peoples of the New World and all pre-Christians, including virtuous pagans such as Aristotle who belonged after death in a limbo fatuorum (the non-pejorative original of our “fools' paradise”). Inability to understand religion characterized the Christian laity in general, including the bottom rungs of the priesthood; these were all idiotae in that their faith was prescribed for them by the expertise of the ecclesiastical and social élite. If only by their size, neither group resembles the incurable minority to whom we now ascribe intellectual disability.¹¹ It is “the possessed and lepers” who are curable in nature and therefore the province of medicine.¹² Their minority condition contrasts with the ubiquity of foolishness, which lies beyond the reach of earthly physicians.

Foolishness in this universal guise shows the influence on Paracelsus of northern Renaissance humanists such as Erasmus and Sebastian Brant. Erasmus's Praise of folly and Brant's Ship of fools both use foolishness allegorically to attack political and ecclesiastical élites. Erasmus spoke for many with his concern about the afterlife of virtuous pagans; it was unfair that they should be denied salvation when Christian élites themselves were foolishly seduced by power and worldliness.¹³ As for the idiotae who relied on élites to prescribe their faith, Erasmus had pointed out that the apostles were (in the Vulgate Bible's terminology) idiotae, unlearned men, too.¹⁴ The hypothetical possibility of salvation for all humans, even though they are all fools, explains Erasmus's quotation from Ecclesiastes, “the number of fools [stulti] is infinite”.¹⁵ As for Brant, historians of psychiatry have argued whether fools were really cast adrift on boats when they should also have been asking whether we would now recognize as fools anyone the boats may have carried. Brant's passenger list includes most members of the human race.¹⁶ None of the 110 types in the contents table remotely indicates the intellectual disability model.¹⁷

All this invites a question. Even if Paracelsus's foolishness, like Erasmus's and Brant's, were metaphorical, surely metaphor only works by its relationship to some positive referent, i.e. a small, pre-existing, pathological group? At the opposite end of the foolishness spectrum from the universal, Paracelsus does indeed identify a limited group which is, if not pathological, then odd. But it does not match the intellectual disability model. In Erasmian fashion it has several guises, and can be traced back to earlier sources. Since metaphor was not just a literary device but could also be explanatory, the narrative slips from universal foolishness to this more specific state and back without any sense that somewhere reality ends and metaphor begins.

The last sentence of Paracelsus's prologue does seem to hint at a distinction between the small group and the universal when he sets fools alongside the “wise” as “brothers … before God”, but the first group here could still be read broadly as pagan.¹⁸ It is only after this that he introduces a discrete group, amidst a host of examples of natural corruption: “fornicators, gamblers, robbers, crippled children, the blind, the deaf, the mute, the lame, the timorous, fools, monsters, the malformed”.¹⁹ It is tempting to assume that this discrete group of “fools” is roughly defined by the intellectual disability model. The other groups on the list do not present problems of historical interpretation, so why should this one? They either have a normative character that clearly does have to be negotiated across the historical distance, such as “fornicators”, or a reasonable claim to some transhistorical correspondence, such as the physical disability of “cripples”. The presence of fools on this list might persuade us to assume such a correspondence, a cognitive disability by analogy with physical disability. However, Paracelsus's premise here is simply that man no longer reflects the divine image; it does not allow for some separate and purely cognitive domain.

Some commentators have suggested that Paracelsus elsewhere “discovered” a connection between goitre and intellectual disability (in the form of cretinism).²⁰ Modern medicine indeed claimed to recognize a link between intellectual disability, thyroid hormone deficit and the iodine deficiency of the Alpine spring waters. In the sixteenth century, however, goitrous deformity belonged to an organic domain which drew no distinction between physiological, cognitive and behavioural. This explains Paracelsus's observation that foolishness is only sporadically related to physical deformity. Goitre is not a “propertium” or defining characteristic of foolishness, he says; it does not indicate stultitia in every case. Modern medicine too acknowledges the variability of any connection between goitre and intellectual disability. But for Paracelsus its variability signifies simply that the condition is to be taken as a whole and thus that “we are no longer in the image of God but have had it taken away”.²¹ At its core is general Adamite incurability, in which neither goitre nor foolishness occupy some merely metaphorical role separable from universal human corruption: all three belong to a single account.

The modern parallelism of intellectual and physical/sensory disability is no help in reading Paracelsus. The text is not esoteric. It reflects the scholastic tradition which he otherwise distanced himself from, and which was as familiar to his readers as his biblical sources. For example, the defectiveness of the Paracelsian fool's “internal instruments” reflects the conventional way of explaining how the faculties of the rational soul such as imagination, judgement and memory, can subsist in states where they do not seem to be operating rationally or at all: sleep, old age, madness. His peers absorbed this tradition from the new textbooks, the most widely consulted of which had added “stultus ac fatuus” to these states.²² Defects in “external senses” were organically related to these internal ones; in a culture where the spoken word was dominant, congenital deafness was the most important of these, as we shall see later.

In addition, Paracelsus's text has a directly theological strand. It follows St Paul in defining the highest part of man as “spirit” rather than the “rational soul” described by philosophers, who found it difficult in their own particular terms to explain how this soul might be independent of corrupt flesh.²³ Like Luther, Paracelsus was wary of “animal” reason; true reason was inspired, not ratiocinative. Fools and philosophers form a single category; they “remain stuck in their own wisdom and do not progress to God's”.²⁴ The question remains, if there are no elements of the intellectual disability model then what is the precise content of their foolishness, the things they do or cannot do?

There are two main characteristics: being holy, and playing tricks. Commentators have already pointed out the “holiness” of Paracelsus's fools. However, what this tradition originally said was that if you are holy then most people, corrupted by earthly desires, will think you foolish. Your foolishness is defined precisely as your lack of such desires; it does not correspond to some transtemporal pathological condition. The Islamic sources of the tradition will bear this out. They mention “idiots” in this Dostoyevskian sense, and the possessed: these are the only two clearly identifiable categories.²⁵ Holiness became sporadically attached to intellectual disability only when the latter, by whatever name, started to appear on the modern historical calendar (the idea of the “innocent” as incapable of sinning is a separate issue). That is, the old tradition of the prophet as fool was later used in the invention of one optimistic variant of intellectual disability. Paracelsus foreshadows this in attaching the holiness tradition to his own fools: a convention originally describing prophets as fools becomes one describing fools as prophets. In scholasticism too, under Arab influence, the supreme human intellectual activity is that of the prophet, who intuits truths directly and does not arrive at them by exercising ratio or apprehending the connecting terms of syllogisms. However, the scholastics ranked the philosopher-reasoner, who does have this syllogistic expertise, only one rung below prophets; Paracelsus and Luther on the other hand ranked him near the bottom because they were suspicious of earthly reason. Paracelsus values his fools precisely because they do not deliberate syllogistically about religion; deliberation, being a function of the rational soul, exists in a temporal realm and therefore has time to be “fashioned”, into “lying and deceiving”.²⁶

The other positive symptom of Paracelsian foolishness is playfulness and tricks [bossen], particularly in speech. These were characteristic of fools in the popular Swiss drama that was used as an educational tool by the Reform movement and took its cue from Erasmus and Brant. Commentators on this drama have distinguished six separate kinds of folly: three negative (fool as intellectually deficient, fool as morally deficient, fool as unbeliever) and three positive (wise fool, pure fool, fool as man in general).²⁷ We have already seen how in Paracelsus's text all these roles overlap. In the drama the main symptoms of so-called “intellectual” folly are laughter-inducing tricks and an eccentric loquaciousness that seems, nevertheless, to use normal syntax and grammar. Our laughter comes at the uninhibited character of this speech and behaviour, which is likewise why Paracelsus aligns his fools with children and drunks. The “intellect” they lack thus consists in properly inhibited speech and behaviour, a sociological phenomenon (as it were) rather than a psychological one. The uninhibitedness of licensed fools or jesters, who tell home truths and whom the “prince” ignores at his peril, is a constant theme in contemporary drama.²⁸ In Paracelsus's time it still provided paid employment in noble households. Its literary and socio-historical sources are Roman.²⁹ Stultitia in this sense was an occupation that could be filled by anyone, a demoted courtier for example; Inge Mans notes one fool who was a graduate.³⁰ But some of those employed as fools already had a natural difference that constituted a prior qualification: achondroplasia, spinal curvature, unusual physiognomy, deaf-mutism, black skin, etc. In addition, professional fools were regularly recruited from the peasantry, for reasons which will become clear later. Whether or not licensed fools possessed one of these natural differences, they learned and acquired the behaviours that went with the job. The distinction between “natural” and “artificial” fools was not necessarily a distinction between people with putative intellectual disability and those simulating it.³¹

Paracelsian foolishness in its more specific sense, then, consists mainly of these two pre-existing, sometimes overlapping behaviours of jester and prophet. The licensed truth-telling of the one and the unmediated insight of the other are valued because they bypass the potentially hypocritical deliberations of the rational soul. In Paracelsus's conclusion he blends these two specific types back into the universal, postlapsarian foolishness of the prologue. He interleaves foolishness as simple truthfulness or piety with foolishness as a failure to avoid earthly corruption. This has a levelling function, as it had for Erasmus. The faith of the élite can be esteemed no more highly than that of the disciples and the mass of ordinary believers or homines idiotae. Paracelsus contributes one extra ingredient of his own which reflects the motto of contemporary Swiss theologians, “Nothing without cause”. Perhaps it is significant that a companion text to the one we have been considering, on madness, is entitled merely De lunaticis, not De generatione lunaticorum: the causes of foolishness, i.e. the incompetent alchemist Vulcans, are the causes of general, Adamite corruption rather than of a specific condition. When historians call Paracelsus an early seeker after the causes of trisomy 21 or phenylketonuria, their error is not that this is anachronistic (they clearly mean it figuratively) but the illusion that he was trying to explain the causes of some particular disability, or indeed that he thought any natural explanation possible.³²

Felix Platter has been called “one of the first to offer a multi-level description of mental retardation”, and the author of the “first” and “fully convincing” account of “cretinism”.³³ He has a more general reputation as a psychiatric pioneer, on the basis of the opening section of his Praxeos medicae where he discusses injuries affecting the internal and external senses.³⁴

Platter's foolishness (stultitia) belongs within this analytic framework of so-called “psychiatric” symptoms, though he himself saw them, conventionally for the time, as merely an organic subset of injuries to bodily functions. Being one of the first to classify diseases as syndromes, Platter applies this approach to brain injuries.³⁵ Instead of a traditional classification linking the intellectual faculties (the three “internal senses” of imagination, judgement and memory) to three corresponding ventricles in the brain, Platter makes a fourfold classification grouping symptoms and associated causes. These are: (1) imbecillitas, relative weakness and diminution of functions; (2) consternatio, absence of functions; (3) alienatio, in which the functions operate inappropriately or excessively; (4) defatigatio, the functions as they operate in sleep.³⁶ If Platter's foolishness were identifiable as our intellectual disability, perhaps it should appear among the symptoms listed under (1) and (2), weakness and absence being the two main subdivisions in nineteenth-century models and still implicit in modern psychology. In fact, Platter's “weakness” (1) does bear a few superficial resemblances to the intellectual disability model, but the term stultitia does not appear; and there are no resemblances at all under “absence” (2), which is devoted to apoplexy, epilepsy, lethargy, catalepsy and profound sleep. As for alienation (3), Platter's opening summary of it suggests mental illness. Given the modern antithesis between mental illness and intellectual disability, then, we might not expect the latter to feature; however some prima facie resemblances, and the term stultitia itself, do appear among the examples here.

Starting with (1) imbecillitas or “weakness”, we find that Platter subdivides it into four: hebetudo mentis (dullness of mind), tarditas ingenii (slowness of apprehension), imprudentia (lack of judgement), and oblivio (memory loss). All of these happen when the “functions of the mind … are not active enough”. Hebetudo and tarditas, as well as imbecillitas itself, can also be symptoms of disease in other parts of the body; at this level of classification, then, they are not clearly distinct from physical symptoms in a dualistic sense. Hebetudo can apply to all three faculties; Platter, not quite in line with the tripartite faculty psychology of the time but echoing Gregor Reisch, labels these as “apprehension or ingenium [standing in for “imagination”], judgement or reason, and memory”. Each of the remaining three subdivisions (tarditas, imprudentia and oblivio) corresponds, albeit only very loosely, to weakness in each one of the faculties. Weak memory is mainly, though not exclusively, identified with old people, while weak judgement (“lack of prudence”) does not seem to fit the intellectual disability model. Is weak ingenium, then, the best fit? It is to be found in people who “barely learn [discunt] how to speak, and apprehend letters and skills [literas et artes] with difficulty”. In its traditional scholastic sense ingenium was the act of apprehending the middle term of an Aristotelian syllogism.³⁷ Its application had broadened by Platter's time, but was still only characteristic of the educated. Discunt in tandem with literas is a formular phrase taken from standard educational vocabulary, suggesting a formal (and substantially oral) curriculum. “Barely learning to speak” in this sense might include by default people to whom we now attribute intellectual disability, but it would seamlessly also cover the lower social classes. In a more strictly medical sense, Platter and his contemporaries saw speech as an “animate motion”, dependent certainly on the condition of the soul's faculties (and chiefly the imagination) but also thereby on transient bodily phases, neither of which necessarily defined the person.³⁸

When he moves on to discuss the causes of this weakness, Platter does so in terms of their impact not on the three ventricles of the brain which house the faculties and which would thus separate out ingenium, but on “the imperfection of the instrument”, which he defines as brain size or shape and above all brain substance. This, as he acknowledges, does not mean that such imperfections may not involve localized defects; localization, however, does not go rigorously with a particular faculty.³⁹ An over-moist texture, for example, extends across the faculties, and across various human types: infants, adults with small brains, amnesiacs. Like most contemporaries, Platter displays far more concern about defects of memory than about those of ingenium and judgement. As for size and shape, a small head may go with a small brain and therefore with “dull operations”, but we cannot know for sure whether there is a correspondence.⁴⁰ He lists the prior causes of a defective brain. These are: “heredity from the parents”; old age; concussion; loss of blood; melancholy; a deep wound to the eye; idleness or over-use of the faculties. The most obvious place for the intellectual disability model here is heredity, since it implies something present from birth. There are only two references to heredity, both occupying only a few words; “clever and industrious people have children like themselves”, and “the ignorant beget the torpid”, an association of intellect with industriousness that hints at the Reformers' linking of education and spiritual self-development.⁴¹

When finally Platter discusses cures for weakness, he groups heredity with old age and external injury as “incurable”.⁴² But he is no determinist; in all these cases industrious “exercise” is a form of nurture that can influence “second” nature (altera natura).

Turning now to the symptoms of (3), “alienation” of the mind, we find Platter using a terminology resonant of Paracelsus: stultitia, moria, fatuitas. Platter uses the three terms synonymously. His foolishness is situated at the same taxonomic level as conditions we would hardly group with intellectual disability: drunkenness, hypochondria, excess emotion, melancholy, mania, demonic possession, hydrophobia and frenzy. All are equivalent illustrations of an overarching “alienation or hallucination”, which means “judging and remembering things which are not as if they were, or things which are wrongly and irrationally, either simultaneously or separately, either in thought alone or in word and deed”.⁴³ In this sense Platter's foolishness on the one hand recalls Galen on delirium, and on the other anticipates later conceptualizations of madness, as a realm of excess antithetical to absence (the absence of abstract thought) in intellectual disability. Platter's own account of absence (2), as we have already noted, does not mention foolishness.

Foolishness under the heading of alienation is dispositional rather than predetermined. Platter lists several examples: infants, old people, the whole human race (“all men in every age inasmuch as all their actions seem to be foolish as Erasmus and Brant have elegantly shown”), “fantastics” who excel in cleverness (ingenium) but whose love of being praised gives them “[asses'] ears” and leads them to buffoonery and ridiculous behaviour, people who are foolish when seized by strong emotions and, in the middle of this disparate list,

There is a link here with Paracelsus's Alpine peasants who drink iodine-deficient “metallic and mineral waters”.⁴⁵ Platter's distinction between some infants and others might justify the pioneering diagnostic role attributed to him if the distinction were a purely intellectual one, though an existing distinction was already made for childhood epilepsy. Perhaps symptoms of melancholy too are evoked in “gazing at the sun”. Poor head shape was a standard item in Galenist psychopathology, and in association with dwarfism it was already linked with goitre, as the iconographic record shows.⁴⁶ Even the sticks between the fingers may recall a pre-existing story about melancholics who idly build models out of sticks and clay.⁴⁷ But, in any case, close attention will show that the symptoms are “behavioural” as much as “cognitive”, to use a modern terminology; that not all the local people observed with such symptoms have a goitre; and most importantly, that they are embedded within a whole array of otherwise differing symptoms whose defining connection is simply that they arouse wonder.⁴⁸ Any other kind of distinction has for Platter only a minor descriptive significance.

The Alpine populations suggest yet another spectrum on which this foolishness lies.⁴⁹ Paracelsus had already written in 1527 about goitre in the Pinzgau valley.⁵⁰ His text on what later became known as cretinism has been accredited with a pioneering role.⁵¹ In it he mentions only bodily symptoms, apart from a passing comment that people with goitre tend “more towards foolishness [torheit] than to skilfulness” and that the water's minerals “destroy the site of the memory”.⁵² Even in his De generatione stultorum the loosely intellectual-cum-behavioural defect was integrated with goitrous bodily deformity in an indivisible whole. Admittedly, Platter seems to dwell on the former. His remark that he had seen such people himself in the Valais presumably refers to the visit he made when young with his father Thomas, who had grown up there. A shepherd born to poor peasants, Thomas Platter had learned to read and write at the age of twenty while running dispatches for the Zwinglian reformers, eventually becoming a respected teacher of classical languages and the printer-publisher of Galen, Vesalius and Calvin. Being an autodidact, he saw his intellectual development as an escape from the ignorance of the countryside and its people, who Zwingli had said were fit only for herding cows.⁵³ In this sense, Thomas followed a broad humanist tradition including Erasmus himself, whose career has sometimes been seen as an attempt to disown the legendarily stupid inhabitants of Batavia, the Rhine delta, where he had grown up.⁵⁴ Thomas's suppression of his own social and (un)intellectual self was integral to his Christian rebirth, and may help to explain his son's view of so-called cretinism. The Alpine foolishness described by Felix stood at the opposite pole from the new urban Jerusalem of the humanist academy; possibly his depiction of “foolishness” sprang from a vicarious nostalgia for his father's great escape. The Valesians who put sticks between their fingers were a social and intellectual distillation of the poor peasant in general who subsisted within Thomas and defined Felix as the great professor of Basle. The same might apply to Paracelsus. He too grew up in an Alpine valley, among the silver mines. Goitre was to be found, he said, wherever there were mines, but in any case it was another area whose peasants were deemed exceptionally stupid, perhaps because they were mostly Slavs. Paracelsus's idiosyncratic Christianity placed an even greater emphasis than Reformers such as the Platters on the individual's potential for knowledge through spiritual self-development. In Paracelsus as in Felix there is thus a spectrum from the foolishness of the goitrous to the idiocy of the village. (In fact, medical investigations cast doubt on whether cretinism as such had ever existed in the Pinzgau.⁵⁵) Platter uses the terms tarditas (slowness of the intellectual faculty) and rusticitas (the peasant condition) synonymously.⁵⁶ This too is a commonplace of classical Roman literature.

Commentators' anachronistic use of the word “cretin” is also worth investigating. The very first reference to its derivation from chrétien (“christian”) and its use in the Valais to denote stupid goitrous people comes only in 1754, in the Encyclopédie. This has led some, following D'Alembert, to regard it as a “folk … term which originated in the patois of the Valais. … an etymological mystery”. The origins are probably not that obscure.⁵⁷ A secondary meaning of chrétien in Old French was anyone unfortunate or materially poor (and thus potentially pious), especially in the countryside. Its use as a label indicating intellectual disability could only have been triggered at a certain point in the emergence of this latter model. D'Alembert and his informant on the matter, Voltaire's friend the Comte de Maugiron, in revealing the etymology of cretinism were actually helping to coin the word and invent the model. Just as Platter made “observations” of the symptoms of goitrous foolishness which “I myself saw” through the lens of an existing paradigm, influenced partly by melancholy and partly by perceptions of social status, D'Alembert saw in the same population his own, quite different symptoms through the lens of Locke's Essay.⁵⁸ To the brief extent (one sentence in a heavy tome) that Platter appears to single out certain Alpine people from the poorer peasantry in general or from those exhibiting the other symptoms listed above, he nevertheless keeps the same elastic term stulti for all of them.⁵⁹

If the sociology seems overdone, consider the great Paduan medical authority Giambattista da Monte. Like his readers, he assumed that labourers did not possess a faculty of ingenium; he “saw” that the brain of a labourer lacked the frontal eminence that ought to house that faculty.⁶⁰ Psychopathology in a member of the gentry was thus identifiable with the normal psychology assumed for a large section of the non-gentle population. Neither da Monte's text nor any that we are considering is a single scientific script about intellectual status that can be read off and applied universally to all humans.

When Platter goes on to discuss the causes of alienation, he divides them into natural and preternatural.⁶¹ In Galenist terms this also signified a division between internal and external causes. Platter identifies the external or preternatural here with the Devil. Internal nature, on the other hand, is not nature as congenital necessity, since it includes the acquired as well as the innate, both stultitia simulata and stultitia originalis. Simulated foolishness is a version of the Roman model we noted in Paracelsus. Men from noble families may grow up enjoying the antics of professional fools, so that eventually they “acquire a habit in it which later becomes irremovable, with the result that they become permanent and genuine fools themselves”.⁶² This again indicates that nature is distinct from necessity: “custom changes nature”. Other people have their foolishness from birth. This stultitia originalis comes “for the most part” from “the seed of the parents”. Again, this is not biological determinism: it is not the parents who ultimately generate the person but God, as author of the soul.⁶³ Platter makes a subdivision here, which Willis will elaborate somewhat differently, between parents whose seed is defective because they themselves are fools and parents who are not fools but whose “seed has acquired some fault”. Platter describes stultitia originalis by the physiological-cognitive-behavioural mix as above. It can progress from the animal spirits to the nerves, in which case such people are born also “deaf, or dumb, or crookbacked, or with goitre or some other defect”. Head size and shape are again not a necessary indicator; sometimes a fault in the size or shape of the brain can only be discovered anatomically, “by opening after death”.

As for cure, the same applies to alienation (3) as to weakness (1). Preternatural causes are from God or the Devil and so are not a matter for the physician.⁶⁴ Attempting to cure poor brain structure would be like attempting to “wash a black person white”; but inasmuch as the defect may partly be dispositional, a matter of brain texture or temperament, it can “sometimes” be amended by age, and “custom can do much”.⁶⁵

Although Thomas Willis prefers the word stupiditas, he uses an array of terms, indicating that the concept itself is not at all rigorous. However, his has been called (presumably with Paracelsus and Platter in mind) “not the earliest systematic discussion of mental deficiency known, but … an early one”, while in psychology Willis is “primitive” but “far more subtle … than Descartes”.⁶⁶ It is reasonable to emphasize his novelty given the influences on him of Pierre Gassendi and Jean Baptiste van Helmont, and given his great emphasis on the functions of the animal spirits and thus on the “power of the invisible”.⁶⁷ Yet he also blends essentially Aristotelian psychology with Galenist medicine in a way that Platter would still largely have understood. The two men share a pre-Cartesian mind-set in which the soul, or part of it, is an incorruptible substance, with the body alone capable of defect and the brain the material domicile of the soul: “the health of the soul begins with the health of the body”.⁶⁸ Willis assembles a range of unreferenced Renaissance sources on psychopathology. Samuel Pordage's 1683 English version, on which historians have based their interpretations, obscures these influences, and Willis's lack of a precise terminology allows Pordage to introduce his own.⁶⁹

In Willis's other works stupiditas is a symptom of melancholy, distinguishing it from mania and phrenitude.⁷⁰ Willis, like Platter, locates foolishness in the imagination. For him it is an affliction of the Gassendist “corporeal” soul, whence it “eclipses” the non-corporeal faculty of intellect or judgement.⁷¹ His analytic framework, following a Renaissance pattern, starts with immediate causes (brain size, shape and substance on the one hand, quality, amount and activity of animal spirits on the other), goes on to antecedent causes (birth, old age, concussion, alcoholism, epilepsy and violent emotion) and finishes with cures.

His immediate causes follow one particular Renaissance tradition in describing the “natural and optimum” state as medium size, spherical shape and balanced temperament.⁷² This serves his own characteristic downgrading of brain structure and substance in favour of brain function. Structure and substance are significant mainly because of their influence on the animal spirits. They are a “natural” cause of foolishness but not a necessary one: “although not always the case, that is very often the way it turns out”.

Antecedent causes are either “original … hereditary … as when fools give birth to fools” (here he uses stulti rather than stupidi, recalling Platter's lapsarian stultitia originalis) and thus “connate”, the product of an ancestral line; or they are “congenite”, caused by the parents' poor performance at the moment of conception, and thus “accidental” and individual.⁷³

Each of the antecedent causes is illustrated. For “original foolishness” (stultitia) the example is obviously his earlier reference to “the offspring of village and country people frequently liable to poor brain texture, [in whose] families we may trace back many generations and find scarcely one bright or clever person”.⁷⁴ Their internal nature thus belongs on the spectrum of class stupidity, country people in particular being beyond the learned doctor's urban remit.

For foolishness (stupiditas) caused individually at birth, his examples are (a) a matter of brain function rather than brain texture or structure, and (b) to be found among his client group. The accident happens not through hereditary taint but precisely because the father is wise and supremely clever (summe ingeniosus): his constant study and contemplation cause the blood to keep too many animal spirits circulating round his brain when they are supposed to be ferried to his “spermatic bodies”.⁷⁵ When “the rational soul is concentrating to the utmost on giving birth to its intellectual offspring … the corporeal soul becomes weaker and less fertile”, and so the physical offspring turn out correspondingly “slow”. There were at least two such cases of contemporary interest. William Harvey's bodily matter stood in loco parentis to his “mentally retarded” nephew and ward William Fowke,⁷⁶ while the form of that matter, i.e. Harvey's rational soul, was acknowledged by Willis to be the spiritual father of his Oxford anatomical club. And the corpora spermatica of Christopher Wren, another club member, were later to produce a “mentally retarded” son, “poor Billy”.⁷⁷ Was this perhaps because Wren had spent too many of his animal spirits on intellectual pursuits, one of which happened to be drawing the illustrations to Willis's textbook on the anatomy of the brain? One illustration depicts “the brain of a fatuus youth”⁷⁸ which Willis, perhaps following Platter's suggestion, had dissected.

Willis's distinction between two types of antecedent cause explains in one fell swoop both the degeneracy of the servile classes and the virtue of his own patients. His story about stupid children born to wise fathers is not, as some have suggested, a “first” modern scientific attempt to move away from ascribing everything to heredity. It was an ancient observation that had already been made by the Roman philosopher and educator Alexander of Aphrodisias, who was enjoying a revived popularity in the mid-seventeenth century, and had subsequently appeared in Albertus Magnus's natural history.⁷⁹ The point of the story is that God, not the parents, is the author of the rational soul.⁸⁰ For Willis it serves the same purpose. His explanatory route, via brain function, enables him to explain the existence of “stupid” traits within families belonging to his own peer group, which without such an explanation would be an embarrassment. There are further accidental causes of foolishness at birth (stupiditas) within the same client group that are not a matter for mutual admiration but are cautionary instead: parental intemperance, drunkenness and effeminacy. These too harm the animal spirits, producing offspring who lack “a great and liberal wit [ingenium]”,⁸¹ that is, the wit of a gentleman, and who thus threaten the future ancestral line with degeneracy or stultitia originalis.

Willis's analytic framework is still partly Aristotelian. The stupidity of the wise gentleman's son is, he says, an “accident”: in Aristotelian terms, this means that it does not affect his prior status as a rational being. It also implies that the stupidity of the stupid peasant's son is, by contrast, an essential property. Accident goes with disease, essential property with the nature bequeathed by the Fall.

Willis also mentions Aristotelian differentiae. “Conventionally”, he says, stultitia and stupiditas are differential characteristics. Stultitia is “absurd, perverse, ridiculous, inappropriate” behaviour, a “laughter-provoking” model of “nonsense and mimicry” such as we have noted in Paracelsus and Platter. In this the animal spirits are unstable and rapid. In stupiditas, on the other hand, the spirits are blunt and slow. However, the suggestion that Willis's stultitia is a “very early description of schizophrenia” and that its contrast with stupiditas marks a distinction between mental illness and intellectual disability does not stand up, because Willis does not allocate them to distinct human types: rather, he wants to revise the “conventional” (vulgo) differentiation.⁸² He uses stultitia both for ridiculous behaviour and for the country labourer. The psychological symptoms of stupiditas and stultitia are in the last analysis related; it is the causes that are different.⁸³

In Willis's discussion of cure, prognosis is related to grades of educability. The normative educational criterion is knowledge of literatura and scientiae liberales, the advanced curriculum of a gentleman. It thus belongs to Willis's client group, who are fit subjects for anatomy in general and for the anatomy of the soul in particular because of the soul's excellence in such people.⁸⁴ All grades below it are therefore to be understood as grades of stupiditas, including that of the many people immediately below who are “skilful enough at the mechanical arts”.⁸⁵ Further down come those who are unfit for mechanical skills but “understand country matters”; others are “unfit for almost any occupation” but can fully learn the basic means of living; and finally there are those who “scarcely understand anything at all or know what they are about [scienter agunt]”.⁸⁶ More precisely, the normative criterion against which the other groups are measured is the ability to “recognize communes notiones”, the religious and philosophical ideas derived from the divine intelligence and handed down by bishops and gentry.⁸⁷ People lacking such abstract ideas need to be trained in them by an “indefatigable master [praeceptor]”. Willis does not indicate whether at these lower levels he is still talking only about his client group; his assertion at the beginning of the book that a healthy soul is the route to “the communion of saints and the societas”, i.e. the religious and social élite rather than the whole communitas, leads us to suspect so. The only people who need to be trained to get ideas are those who by virtue of their ancestral line ought to have them in the first place.

Even in the lowest two categories, training can change nature. In an echo of Cartesian matter-in-motion, “however coarse and dense the animal spirits may be they will nevertheless forge some tracks or channels, albeit imperfect ones, in which they can expand”.⁸⁸ Where there are innate or acquired states in which absence of thought (amentia) or of movement (stoliditas) frustrates the attempt at training, there is still scope for providential transformations. Dull-brained or dull-spirited children can later become capable and teachable, and a hot fever can suddenly cure adults assumed to be foolish. Examples of such cures include a court jester described as fatuus, and an elderly amnesiac.⁸⁹ Elsewhere in the book stupiditas covers epileptics too, and he quotes biblical sources to show that they are curable by prayer.⁹⁰

Willis's terminology for the distinct grades of foolishness comes from the Roman comic playwright Plautus.⁹¹ He shares this influence with John Dryden, who was Willis's contemporary at court and in the Royal Society and in whose satirical poetry “stupidity” was the core concept. The terminology itself does not indicate a strict classificatory hierarchy. The focus is on brain (dys)function, and this too exists along a spectrum; there is ultimately no separate pathological niche. As for the stultitia originalis of country labourers, this does not fall within the disease model at all, since their brain dysfunction does not arise “accidentally” but is the product of a degenerate, “original” structure and substance. In country labourers, says Willis, even the animal spirits probably consist in gross matter rather than in their normative fineness. Treatment would surely be wasted on them. The crassum ingenium (coarse understanding) attributed to Batavian peasants by Erasmus, Lemnius and others corresponds to Willis's crassam texturam and coarse spirits.⁹² It is also worth noting here a further resonance with Platter: of the scores of scientific virtuosi counted among the spiritual sons of William Harvey, Willis alone came from a family that was both rural and non-gentle.⁹³

The vocabulary of Pordage's translation echoes Culpeper's mid-century radicalism⁹⁴ and reflects the anxiety about reason that affected dissenters such as himself. For the whole sector of the population lacking common ideas Willis had used Plautus's epithet bardi (“slow”), exactly as he had for the slow offspring of wise fathers. Pordage's translation, however, singles out and labels these latter; they are “changelings”. This term, once used in theology to denote people with a defective will, seems in the 1660s to have been reassigned to those with a defective reason. It was a highly restricted group label adopted by the dissenters and Locke, for whom changelings are an unnatural species occupying the hypothetical interstice between man and monkey and lacking a soul.⁹⁵ For Pordage, who had been raised as a follower of Jakob Boehme in the belief that the earth would become heaven and that hell was somewhere among us, the word may have had demonic overtones. The Royalist Willis on the other hand wanted to show that all men had an achievable modicum of reason in their rational (incorruptible) soul, in spite of the effect on it of injuries to the corporeal soul. This was roughly the line, give or take its Gassendist overtones, of the Restoration bishops. Reason was as important to them as to the dissenters, but while they saw themselves dictating its contents the dissenters saw it as the autonomous possession of individual believers.⁹⁶ At another point Pordage renders a single use of the same word bardi hyperbolically as “dull or senseless Beetles [mallet heads] or the more dull Loggerheads or Blockheads”.⁹⁷ He uses “dull like changelings” to translate Willis's Mορυχου μωροτρον (“more sluggish than the Soak”, i.e. Bacchus), an epithet usually applied to drunkenness or melancholy.⁹⁸ The Latin caption to the above mentioned Wren drawing in Willis's textbook on the anatomy of the brain shows Willis perhaps consciously distancing himself from the quasi-demonic language of some contemporaries; he calls the youth “fatuus, though he might commonly be called a spirit [Lemur]”.⁹⁹ Pordage translates fatuus here as “changeling”, the connotations of which are much closer to “spirit”.¹⁰⁰

Rarely is these authors' “foolishness” strictly pathological. It is usually second rather than first nature. And its boundaries are faint, so that it is always merging into some other, more firmly established category. Among these are Adamite degeneracy, already existing satirical discourses, infancy or old age, diseases originating in parts of the body other than the brain, deafness and mutism, eccentric behaviour, the simulated or mercenary folly of the jester, mental illness and in particular melancholy, and the attributes of peasants and labourers beyond the doctor's domain. It is difficult to recognize in this foolishness the characteristics outlined in my introduction as defining intellectual disability, or to read the texts as discoveries, pioneering diagnoses or strictly medical versions of something positive and transhistorical. In methodological terms, looking up stultus, stupidus or fatuus in the index of a Renaissance medical compendium cannot be assumed to work in the same way that looking up mania or phrenesis may, at least partly, work for the historian of mental illness.

The last two of the categories into which foolishness merges are particularly instructive. Melancholy, the category most properly the domain of the doctor, had long filled one side of the metaphysical template of slow versus fast within which “mental” processes tend to be reduced, the other side being mania. It was only well after the early modern period that this same template became transformed into one of intellectual disability versus mental illness. In Pieter van Foreest's case study of stultitia,¹⁰¹ whose symptoms in any case consisted only of stammering and a penchant for dressing up, the cause was excessive phlegm. Van Foreest contrasted this with the excessively dry brains of the Alpine population.¹⁰² His point was that foolishness can be either moist or dry, whereas melancholy is only dry; thus the former can mimic the latter and they are hard to tell apart.¹⁰³ Van Foreest is only interested in a discrete foolishness to the extent that it can tell us something about melancholy.

As for the intellectual attributes of peasants, it is instructive to trace back the actual characteristics attributed to modern intellectual disability and see to whom they were formerly attributed, rather than to trace back the surface terminology with its dubiously transhistorical appearance. Inability to think abstractly was characteristic of all the semi- and uneducated laity or homines idiotae (even by Willis's time this still meant all servants and labourers); it was also characteristic of all women and, albeit much less consistently in this early period, of black people.¹⁰⁴ The modern emergence and categorization of a previously non-existent “intellectual disability” seems to have been a distillation of the attributes of these social groups. The age of psychometrics has forced the egalitarians among us to view the process in reverse, and to see bricklayers, women and black people as having been unjustifiably tainted with the characteristics of a positively existing group of “intellectually disabled” people. To obtain a clearer picture of the distillation process we should look not at medicine but at theology (and to a lesser extent jurisprudence and political theory), where we can trace it via the crooked and intermittent path that leads from pre-modern theology to modern psychology. In the medical texts I have analysed it is scarcely visible at all.

The weakness of the category boundaries, especially in this last instance, suggests that it would be wise to approach both foolishness and intellectual disability not just as discursive formations but also as aspects of more fundamental changes in material historical conditions.¹⁰⁵ This may mean that they require a distinctive approach, separate from that towards mental illness or physical disability. It is just possible to maintain that a Galenist or even a Hippocratic doctor might have recognized a twenty-first-century manic depressive in terms we could mutually recognize, as they certainly might a paralytic, but they surely would not have recognized our “intellectually disabled” person since the entire conceptual framework was missing. The problem is that intellectual disability has so far been treated only as a footnote to histories of “intellectual” pathology dominated by mental illness¹⁰⁶ or to histories of “disability” dominated by physical disability.¹⁰⁷

Other conclusions emerge from looking at the historical distance between periods in terms of the doctors themselves, firstly in their relationship with patients, and secondly in the religious components of medical knowledge.

Medical thinking about diseases which one may oneself catch, or pain which one may oneself suffer, partly involves imagining oneself in the patient's state. But although the modern study of intellectual disability follows a disease model, its diagnostic approach does not start from imagining oneself as an “intellectually disabled” person. Neither people of normal intelligence nor abnormally clever people such as doctors or medical historians can vicariously experience, in their own imaginations, the mental functioning of a creature deemed innately and incurably incapable of the “abstract thinking” which they themselves cannot help but exercise. Stultitia and stupiditas on the other hand may have been conditions with which Galenist doctors could have experienced empathy, unlike ourselves with intellectual disability. If these conditions were perceived in the same terms as the doctor's own experience in himself of certain brain states—lethargy, drunkenness, the after-effects of intense emotion, the “dull” humour of melancholy, the moment of “stupor” between crisis and resolution in bodily illness, or for five minutes after a nap—then he could know these same symptoms of foolishness (for example, Platter's “dullness”, “excessive languor” and “sluggishness” of the internal senses) in his patient.¹⁰⁸ The empathetic capability of modern doctors extends, ideally at least, to a near-universal client group consisting of somehow intelligent and consenting individuals, a group whose normative limits are bounded only by the small marginal realm of intellectual disability. Earlier doctors' empathetic capability, which on the contrary did embrace stultitia, stupiditas etc., extended as far as their client group too, but it was a group whose normative limits were more narrowly defined in a sociological sense.

In spite of all the work of the last three decades on the history of madness and the history of science more generally, there is still a temptation to suppose that these medical men were all writing in a strictly medical capacity and that their “discovery” of intellectual disability is coterminous with a gradual discarding of theology. It creates the illusion that Paracelsus, being the oldest, is the most theological, Willis the least. The question, however, is not which medical writers first gave a precise diagnosis of intellectual disability, but how medical men first became involved with a concept born largely from a theological matrix. The fact that Paracelsus's text does indeed have overtly theological rather than medical aims then becomes a red herring. At least he did not seek the causes of foolishness in diabolic magic, unlike some of those who came after him. Willis's text has the (false) appearance of being the least theologically oriented of the three not because it was written later but merely because of the particular slant his religion took. Restoration Anglicans like himself sought to accommodate reason in religion, partly as a reaction against the sectarian enthusiasms of the mid-century. At the same time, in their attempts to explain human behaviour, they were turning their attention away from the blood and directly towards the rational soul.¹⁰⁹ Reason and the rationality of the soul were likewise important to the Anglicans' dissenter opponents. But whereas Anglicans maintained the universal possibility of salvation, the dissenters and some of their allies, such as the hugely influential theologian Richard Baxter and ultimately John Locke, sublimated the faith of the elect within a new doctrine that jettisoned divine “spiritual” intelligence in favour of a specifically human “natural intelligence”, acting as the substructure of faith. This doctrine left “idiots” and “changelings” on the outside, just as reprobates had been left to perdition when faith alone was the key.¹¹⁰

Demonic or quasi-demonic explanations of cause thrived in this process, and were absorbed into a more individualized pathology. In this sense Pordage's “changeling” label modernizes Willis by breathing new life into certain Reform beliefs of the Platter era. Commentators in search of a “first” modern psychiatrist have tried to ignore or dismiss the importance Platter attached to the devil in his aetiology of mental alienation.¹¹¹ Not only does any reading of the text show this dismissal to be unwarranted, his successors paid even more attention to demonic causes. Caspar Bauhin, for example, who took over Platter's post as head of the medical faculty in Basle, was one of those who contributed to a picture of the “changeling” as a preternaturally caused quasi-human prefiguring more modern accounts of intellectual disability.¹¹² Theology's formative influence on psychology, replacing that of scholastic philosophy, was rising throughout the Renaissance and until the late seventeenth century at least.¹¹³ Perhaps it is rising still, in view of the current attempts by cognitive and behavioural geneticists to perfect our rational souls through genetic engineering.

No doubt a more positive analysis is possible. Current interest in the body and in its changing relationship with the soul and the self might help us build up a picture of the medical mind-set of the early modern period and spend less effort on pointing out what it did not contain. It would then be possible to look for any elements of a modern intellectual disability model that may indeed have been emerging within the organic psychopathology of Galenist medicine.¹¹⁴ However, no such step is possible without first challenging an axiom that informs not only medical history but the current mind-set of the medical profession, of biotechnology and bioethics, and justifies our own ways of categorizing our fellow humans by projecting such categorizations on to the past.