No Ghost in the Machine: Talking Heads in Sylva

At the end of Century II of Sylva Sylvarum, Bacon mentions the possibility of making a talking puppet by studying the principles that allow for the production of sound in animate and inanimate bodies:

[S]o that if a man, for curiosity or strangeness sake, would make a puppet or other dead body to pronounce a word, let him consider, on the one part, the motion of the instrument of voice; and on the other part, the like sounds made in inanimate bodies; and what conformity there is that causeth the similitude of sounds; and by that he may minister light to that effect. (SS:199)

Talking heads – of natural or artificial provenience – had been an object of fascination starting with the late Middle Ages and would continue to be one up to the eighteenth century (nineteenth, if we integrate them into the larger tradition of the “learned man’s android” as detailed by Sarah Higley [1]).  Yet the source of their fascination changed dramatically during this period, following a larger trend of naturalizing the preternatural and integrating it into “scientific” explanatory paradigms.[2]

On the natural front, Aristotle had declared severed talking heads an impossibility, on account of the fact that the lungs and windpipe were needed to produce sound (On the Parts of Animals, III:10). Despite this pronouncement, severed talking heads continued their career as a literary and hagiographical motif. Virgil and Ovid depicted the head of Orpheus, still calling out to Eurydice as it floated off to the sea. The heads of Christian saints were sometimes said to keep talking even after they were cut off (St. Edmund the Martyr in Abbo of Fleury’s Passio Santi Eadmundi a good example of this).

On the artificial front, brazen talking heads came to be regarded, in the late Middle Ages, as a symbol of dangerous knowledge. There was little insight into how they were produced, besides the fact that learned men studied the stars for favorable conjunctions to make them. Brazen heads were not to be trusted: legends had them telling the truth in a cryptic manner, so that those who relied on their advice were often led to their death. Among those who were said to have produced or owned a brazen talking head were Virgil (probably because he was a source for the legend of Orpheus), Pope Sylvester II (who was said to have died because he relied on the advice of said instrument), Robert Grosseteste, Albertus Magnus (whose creation was sometimes said to have been destroyed by Thomas Aquinas) and Roger Bacon.[3]

The cover Greene's play, showing Friar Bacon's brazen head

The cover of Greene’s play, showing Friar Bacon’s brazen head

Roger Bacon probably became the most famous of the group, as his example was later used in a popular Elizabethan play of Robert Greene’s, The Honourable History of Friar Bacon and Friar Bungay (~1594). In Greene’s play, the brazen head shatters, after it utters only a cryptic pronouncement (“Time is. Time was. Time is past.”), and Bacon eventually renounces his magic. In this example, as in earlier others, the source of the brazen head’s powers was demonic. But there is something else worth noting in this play, and that is the skepticism displayed by the Oxford doctors towards Bacon’s discovery, which reflects a wider change in attitude during the period. As one of them says:

Have I not pass’d as far in state of schools,
And read of many secrets ? Yet to think
That heads of brass can utter any voice,
Or more, to tell of deep philosophy,
This is a fable Æsop had forgot.

The possibility that someone had ever built a real, autonomous talking head by consulting the stars was challenged by Della Porta, while at the same time an alternative explanation was given: it was possible that the talking head relied on long pipes conveying the sound of someone’s voice from a distance (Natural Magick, XIX:1). The same disparaging of the initial claim, followed by an explanation based on sound being carried through pipes is to be found in Campanella’s Magia e Grazia. (This explanation also happens to nicely parallel an episode from Chapter LVII of Don Quixote, where, steeped as he is in medieval romances, Don Quixote is deceived by a talking head relying not on supernatural powers, but on a system of pipes with a sharp-witted student at the end of them. The man owning the head claims that it was built by “one of the greatest magicians and wizards the world ever saw” who “observed the points of the compass, (…) traced figures, (…) studied the stars, (…) watched favourable moments, and at length brought it to the perfection we shall see to–morrow.”)

While Bacon, like Della Porta, offers a naturalistic basis for building a talking head, his project is far more ambitious, because it deals with imitating and not merely conveying the human voice, by deciphering what makes it possible in the first place.

Sources/Further reading:

[1] Higley S.L.; (1997) The Legend of the Learned Man’s Android. In: Hahn, T. and Lupack A. (eds.), Retelling Tales. Essays in Honor of Russell Peck

[2] Daston, L., & Park, K. (2001). Wonders and the Order of Nature, 1150-1750.

[3] Mills, R; (2013) Talking Heads, or, A Tale of Two Clerics. In: Santing, C. and Baert, B. and Traninger, A., (eds.) Disembodied Heads in Medieval and Early Modern Culture

Helleborus niger

Among the important plants that Francis Bacon mentions in his experiments in consort touching purging medicines (Sylva Sylvarum, Century I) is the plant of hellebore, considered to be a helpful remedy moving the body to „expell by consent”. Black hellebore is counted among the medicines that have a „loathsome and horrible taste” and by this quality moves the stomach to surcharge and expell. It is interesting to see that Bacon does not consider hellebore to have any occult quality and insists on the fact that purging medicines in general, when better understood, can be properly administered. Thus, the following short presentation on the plant of hel8-Helleborus-Niger-Black-Hellebore-or-Christmas-Rolebore.

The hellebore plant belonging to the helleborus genus has been known ever since antiquity to posses powerful purging qualities. The physicians following Hippocrates used the Helleborus niger, known today as the Christmas Rose and the Veratrum Album-known as the White Hellebore- as diuretic remedies. The Hippocratic physicians, nevertheless, did not acknowledge the pharmaceutical differences between the two plants and used them both for the same purposes, although only black hellebore was later regarded as an efficient cure for obstruction.

Black hellebore has kept its medical importance up until today and it is still listed in some of  the pharmacological manuals. If we look into the pharmacological hand-books of the late sixteen-century, we find out that hellebore was used as a powerful remedy against melancholy and was thought to have the virtue of evacuating molesting humours that would lead to insanity and depression. By the late sixteen century, the difference between the species, their habitat and cultivation methods was already known although the apothecaries still appealed to Pliny and Galen for information regarding the plant. Hellebore was highly esteemed by the „chymick phisicans” too, who would mix it with various other tinctures and oil and alcohol (spirit of wine), a mixture that „could be easily been given to children against the dropsy and all melancholy affections”(du Chesne, 1591) The Alchemists included hellebore in the category of opiate medicines which, according to some of them, proved to be efficient remedies against colics, pleurisy and gout and also able to provoke sleep and appease disease of the respiratory tract and the rheuma. The controversy around opiates is common to sixteen century alchemical debates concerning plants that would have a strong and possibly poisonous impact on the human body. This might be one of the reasons why hidden, occult virtues or qualities have been attributed to it.

Although parts of it, are still used today in homeopathy, the drug made of the hellebore plant is seen to be as highly narcotic.


Bacon, Francis. 1857–74. The Works of Francis Bacon (SEH), 14 vols. edited by James Spedding, Robert Leslie Ellis and Douglas Denon Heath. London: Longman (repr. 1961–63, Stuttgart-Bad Cannstatt: Frommann)

Quercitanus, Josephus. A brief answer of Josephus Quercitanus Armeniacus Doctor pf Physick to the exposition of Jacobus Aubertus Vindonis: Concerning the origins and causes of metals, London, 1591

Prioreschi, Plinio. A History of Medicine, Vol II: Greek medicine, Horatius Press, Omaha,1996

Turner,William. The Name of Herbs in Greek, Latin, English, Dutch and French, London, 1548


Glossary: Appetite

Works: Abecedarium novum naturae (OFB XIII)

Sylva sylvarum (SEH II)

The term ‘appetite’ is a key concept within Baconian natural and moral philosophy, though Bacon never gives a definition or a clear explanation of the term. What can be understood from the several discussions about the appetites is that they are the causes of all actions in nature, both in the inanimate and in the animate realm, and at the distinct levels, from the last particles of matter to the most complex beings. At a micro level, they are also the causes for the existence of compound bodies. From the Abecedarium novum nature it becomes evident that there are four classes of appetites of bodies: for preserving themselves, for bettering their condition, for multiplying themselves and applying their form, and for imposing themselves upon other bodies (ANN, OFB XIII, p. 197). For each of these appetites there are several correspondent simple motions.

Simple motions and their correspondent appetites (ANN):

Of resistance

Of connection

Of liberty                                            self-preservation

Of self-continuity


Of hyle

Of the mayor congregation

Of the minor congregation                bettering of their condition

Of disposition


Of assimilation

Of excitation

Of impression                                     propagation of their nature

Media of motion


Royal motion

Spontaneous motion

Of repose                                           enjoyment of their nature

Of trepidation

In her book Entre el atomismo y la alquimia, Silvia Manzo defines motion as the effect of an appetite and the appetite itself. There is no difference for Bacon, says her, between the tendency to motion (appetite) and the motion itself. Moreover, she discusses the relation between the appetites of matter and the distinct kinds of good propsed in ethics – comun and private (pp. 69-82), both for inanimate, and for animate matter. Tangible matter has two main appetites, to reject vacuum and to consolidate its proper nature. On the other hand, spiritual matter has three appetites: to enjoy its proper nature, to multiply itself upon other spirits and to escape and unite with their connaturals. The main processes in nature (desiccation, liquefaction, putrefaction, and vivification) are the effect of these appetites and the relation between them (pp. 83-85) and between tangible and pneumatic matter.

Most important experiments in SS in which it is given an explanation based on the appetites of matter are: 24 (appetite of continuation in liquids), 33 (appetite of union of dense bodies), 290 (appetite to receive the sound), 293 (appetite of union in bodies), 300 (appetite of the stomach), 336 (appetite of issuing in spirits), 713 & 714 (appetite to expell what strikes the spirits), 716 (appetite to revenge), 763 (appetite not to move), 800 (appetite of bodies to take in others), 831 (appetite in the stomach), 845 (appetite of not discontinuing), 846 (appetite to conitnuity), 931 (venenous appetite of musk, amber, civet), 944 (appetite of contact and conjunction).

Glossary: Spirits


Spirit(s) is one of the most important Baconian terms, featuring prominently in all his works. In the natural historical works (see below) the term is strongly linked/intertwined with Bacon’s ‘pneumatical’ (i.e. ‘spiritual’) matter theory.

Works: Sylva sylvarum (SEH II)

Historia vitae et mortis (OFB XII)

Historia densi et rari (OFB XIII)

De vijs mortis (OFB VI)

For Bacon there are two kinds of matter: tangible and pneumatic. The pneumatic one is also called “spirit” and it is present in every tangible body, being the cause of all actions and visible processes that we observe in the natural world. If the tangible matter is inert, the spirit is very active. In SS experiment 98, Bacon offers a definition of the spirit: “For spirits are nothing else but a natural body, rarefied to a proportion, and included in the tangible parts of bodies, as in an integument. And they be no less differing one from the other than the dense or tangible parts; and they are in all tangible bodies whatsoever, more or less; and they are never (almost) at rest; and from them and their motions principally proceed arefaction, colliquation, concoction, maturation, putrefaction, vivification, and most of the effects of nature.” A similar definition is to be found in HVM: “a body thin and invisible, yet something real with place and extension” (OFB XII, 347-49). it is an important feature in Baconian philosophy that in order to perform changes upon nature, the philosopher has to manipulate the spirits, and this is done through governing their appetites.

There are two main kinds of spirits: non-living (‘mortuales’) and vital (‘vitalis’), the first in inanimate beings and the second in animate ones. There are two main differences between them: spirits of things animate are all continued with themselves, and are branched in veins and secret canals and “the spirits of animate bodies are all in some degree (more or less) kindled and inflamed, and have a fine commixture of flame, and an aerial substance. But inanimate bodies have their spirits no whit inflamed or kindled” (SS, exp. 601). As a consequence of these differences, Bacon finds seven differences between plants and inanimate bodies: firstly, plants are determinate and figurate by the spirit, secondly, pants do nourish, while inanimate bodies do not. Thirdly, plants have a period of life, inanimate bodies not. Fourthly, they have a succession and propagation of their kind, while inanimates do not have it. The last three differences are: metals are more durable than plants, they are more solid and hard and lastly, they are holly subterranean (SS, exp. 601-606).

Within the animate bodies, there are again two types of spirits: those of plants and those of living creatures (animals). Again there are two main differences between them. Firstly, in living creatures the spirits have a cell, while in plants they are organized in branches; and secondly, the spirits of living creatures have more flame and less air, while the spirits of plants are more airy and less flamy, even though, being pneumatic, both are airy and flamy to some degree. But there are also eight secondary differences as a consequence of the two primary ones: a)  plants are fixed to the earth, while living creature are severed; b) living creatures have local motion, while plants do not; c) living creatures nourish themselves from their upper part, plants from below; d) plants have their seed and seminal parts uppermost, while living creatures have them lowermost; e) living creature have a more exact figure than plants; f) living creatures have a greater diversity of organs and inward figures than plants; g) living creatures have sense, plants do not; h) living creatures have voluntary motion, while plants do not. In animate bodies, there are also inanimate spirits, in a constant struggle with the tangible matter and with the other pneumatics. These non-living spirits are responsible for the consumption of bodies and the death of things, while the animates are responsible for the process of nourishment of the body where they live (SS, exp. 607-612 and HVM, OFB XII, p. 351).

The non-living spirits contained in the body want to get out and unite with the air, given their airy nature. This appetite has five consequences: if the spirit is detained in the body, but moves violently there follows colliquation (as in metals), if it moves mildly, it follows maturation and digestion (fruits and liquors), if the spirits protrude a little and the movement is confused, putrefaction follows (as in rotten fruits, flesh, shinning wood), if the motion is ordered, then vivification and figuration follows (as in the creatures bred of putrefaction and those perfect); and if the spirits leave the body there follows desiccation, induration, consumption (as in bricks or in the evaporation of liquids) (SS, introduction to exp. 329).

Sulphur quaternion


Mercury quaternion

Tangibles bodies (with attached   spirits)



Salts (subterranean and in organic   beings)



Oil and oily inflammable substances


Juices of animals and plants

Water and crude non-inflammable   substances


Pneumatic substances

Terrestrial fire


‘Attached’ animate and inanimate   spirits

(in tangible bodies)



Sidereal fire

(planetary matter)

Heaven of the fixed stars


(planetary medium)

Graham Rees, The structure of Bacon’s matter theory,  “Matter Theory: A Unifying factor in Bacon’s Natural Philosophy,” Ambix, 25 (1977), p. 117.