A “Careful Examination of All Kind of Phenomena”: Methodology and Psychical Research at the End of the Nineteenth Century

Abstract

What does psychical research teach us about the development of control strategies, not only in terms of improved experimental settings but also as criteria for data collection and interpretation? In this paper, I explore this question with the help of three historical cases: (1) Michael Faraday’s 1853, experiments on table turning, (2) Robert Hare’s Experimental Investigations on Spiritual Manifestations (1855), and (3) the later attempts at analysing telepathic phenomena statistically, as it was theorized by Edmund Gurney (1884, 1886) and criticized by Charles S. Peirce (1887). These cases do not aim to exhaust the topic of psychical research and of its methodological issues, but rather to point at methodological ideas as they emerge from the actors’ strategies and practices. Eventually, psychical research allows to investigate such methodologies all while acknowledging that their framing happens on the backdrop of religious, social and institutional concerns.

6.1 Introduction

It was a warm night in Boston on June 26, 1857, and behind the shut windows and tightly drawn curtains of Apartment 12, on the third floor of the Albion, at the corner of Tremont and Beacon street, it was even warmer. Inside the apartment, in a room dimly lit by gas lamps, Professor Benjamin Peirce – the United States’ foremost mathematician – was sweating profusely. He was crammed on a bench inside a wooden box, some musical instruments (two tambourines, a fiddle, a banjo, and a tin horn) gathered between his legs; two boys, tied with ropes, were sitting at his sides. The boys faced each other; the ropes fastened so their hands were behind their backs and their ankles together: they could not bend forward toward the Professor nor toward the musical instruments lying at his feet. The three were participating in a spiritual manifestation: the boys as mediums, and Professor Peirce as their control.

Bizarre as this setup might appear, the examination of psychical phenomena by a committee of experts was not an isolated case in the nineteenth century. The one just mentioned exhibited an incredible display of resources among both controllers and committed spiritualists. Besides Benjamin Peirce (1809–1880), the committee included the naturalist Louis Agassiz (1807–1873), the chemist Eben Norton Horsford (1818–1893), and the astronomer Benjamin Apthorp Gould (1824–1896). These last three had studied with some of the most eminent scientific men of Western Europe –Alexander von Humboldt, Justus von Liebig, and Carl Friedrich Gauss, respectively – before settling at Harvard and surroundings.¹ To ensure that such a jury would have a chance of witnessing relevant manifestations, some of the most powerful mediums of the country had been invited, including the Fox sisters. The event was a response to a mediumship scandal that had happened earlier that year at Harvard University. The scandal involved a few faculty members and a Divinity student, the latter in the role of the fraudulent medium. To capitalize on the attention, the newspaper Boston Courier offered a $500 prize for successfully demonstrating spiritual manifestations. A certain Dr. H. F. Gardner took up the challenge (Moore 1972, 494–95).

The 3 days of experiments at the Albion were not the first attempts at investigating psychical phenomena in a controlled setting, nor were they to be the last ones. In the last decades, a growing body of literature has examined the connections of psychical research with ordinary science, highlighting the positivist and naturalist motivations of many researchers (Luckhurst 2002; Owen 2004; Noakes 2019) and their role within the process of institutionalization of psychology (Coon 1992; Plas 2012; Sommer 2012). Moreover, in a context in which physics and engineering were constantly expanding the boundaries of the possible, psychical phenomena often appeared just as plausible as the possibility of long-distance communication through the telegraph. Besides being suggestive, this analogy well represents the idea of a continuity between physical and psychical forces, to be investigated through scientific experimentation.

Other commentators highlighted how the rejection of psychical phenomena and of their scientific investigation was often motivated by religious sentiments, in so far as the belief in spirits communicating through table turnings and rappings was perceived as impious and/or materialistic (Moore 1972; Sommer 2018).² Even the journalist writing the Boston Courier report confessed his religious concerns when witnessing the Albion séances:

…there are certain things of which I have no objection to say that I am afraid. I trust I am afraid to do anything deliberately, which would lessen my self-respect, – afraid of too intimate association with those, whom I do not conceive deserving of respect, – afraid of disobeying the instincts of my understanding, – afraid of violating the manifest law of God. I have never ceased to consider what was professed and pretended by the spiritualists as impious – what was performed by them as puerile. If the manifestations claimed by them, as within their power, actually corresponded with their pretensions, I should have no hesitation in ascribing them to diabolical agency… (Author Unknown 1859, 23; emphasis in original)

In spite of the rhetorical formulation of this nineteenth-century journalistic piece, it is clear that some elements of belief influenced the judgement of both parties involved. Belief indeed played a role in almost every case that I discuss in this chapter; however, it is interesting to note that belief was not, by itself, able to determine the type of investigation that the different actors chose to pursue, nor the way in which they chose to control for the phenomena that they wanted to investigate. Gender and class also played an important role in structuring the setting of psychical experiments and in negotiating positions of authority (Taylor 1996; Owen 2004). Charles S. Peirce, son of Benjamin Peirce, when evaluating a collection of testimonies of telepathic phenomena, succinctly stated: “Women, children, sailors, and idiots are recognized by the law as classes peculiarly liable to imposition. If sailors’ yarns are to be admitted, the reality of ghosts is put beyond doubt at once, and further discussion is superfluous” (Peirce 1887b, W6, 138).³ All of these elements constitute the background of the present account, which focuses more narrowly on how different investigators came up with and defended different strategies of control. Such strategies were crucial to the interpretation of the phenomena under investigation, including to which branch of science (if any) they belonged.

“Psychical phenomena” is an umbrella term that referred generally to phenomena allegedly produced by spiritual forces or entities; in this chapter, we encounter four instances of these manifestations – table moving (Sect. 6.2), mediumistic communication (Sect. 6.3), “telepathic” communication (Sect. 6.4), and apparitions (Sect. 6.5). All of these instances offer the opportunity to capture different declinations of “control.” First, “control” is here mostly about controlling the setting (i.e., the instrument(s), the people’s perceptions, or the people’s testimonies), rather than about controlling a result against a comparative trial (as it is most often the case for the chapters in this volume; see Schürch’s contribution, for example). Second, in some cases “control” is an actors’ term (see Sect. 6.4), a rare occurrence in this volume. Third, the actors presented in this chapter deploy two distinct but parallel (and ultimately intertwining) strategies of control, which are called – by the actors themselves – “experimental” and “historical.”⁴

The experimental strategy is distinguished by its use of apparatuses; in this chapter, small tables are the simplest device for detecting and interpreting spirit messages. The historical strategy relies instead on collecting, evaluating, and publishing testimonies, and on attempting to statistically quantify their relevance. The experiments of Michael Faraday (Sect. 6.2) and Robert Hare (Sect. 6.3) illustrate control strategies in traditional experimental settings,⁵ while Edmund Gurney’s contributions to the Society for Psychical Research (SPR) show the complexity of the experimental-historical interaction from methodological and epistemological perspectives (Sect. 6.4). Finally, Gurney’s controversy with Charles S. Peirce over cases of spontaneous telepathic manifestations illustrates the challenge of controlling testimony within the historical method (Sect. 6.5).

6.2 Control as Education: Michael Faraday’s Experiments on Table-Turning

In 1853, Michael Faraday (1791–1867), who at the time was already one of the greatest scientific authorities in Europe, took the time and trouble to conceive an experiment on the phenomenon of table moving. His research resulted in three publications: a brief letter to the Times (appearing on June 28, 1853, Faraday 1853a); a longer exposition for the London Athenaeum (July 2, 1853, Faraday 1853b); and a description with figure for the Illustrated London News (July 16, 1853, Faraday 1853c; Fig. 6.1). While Faraday deplored in more than one instance the fact of having had to engage with such a topic, he was clearly aware of its importance both from an epistemological and a moral perspective.

Fig. 6.1

Illustration of Faraday’s table-turning experiment. Source: Illustrated London News, July 16, 1853

Faraday began by testing various materials in contact with the tables and the participants’ hands. He determined that interposing such materials between wood and skin didn’t interfere with the table’s movements. He then conceived an experiment to ascertain the nature of the force operating on the table. This experiment was fully within the methodological constraints of physical investigation, as he declared in the opening paragraph of the Athenaeum letter:

the proof which I sought for, and the method followed in the inquiry, were precisely of the same nature as those which I should adopt in any other physical investigation. (Faraday 1853b, 801)

Participants in séances claimed (1) that the table would move first, and that the hands would follow; and (2) that their hands were laying still on the table’s surface and/or pressing downwards only, while the table “turned” and hopped in any direction. According to Faraday, they did not give their testimony in bad faith:

The parties with whom I have worked were very honorable, very clear in their intentions, successful table movers, very desirous of succeeding in establishing the existence of a peculiar power, thoroughly candid, and very effectual. (Faraday 1853b, 801)

Their séances were “effectual,” meaning that the participants were predictably successful in moving the table. However, Faraday could not detect a force that could justify the movement, whether electrical, magnetic, or otherwise. The only plausible option seemed to be that the table was moved by mechanical force impressed by the participants – yet they resolutely denied it. According to their testimony, the table appeared to be moving by itself.

In designing his experiment, Faraday was influenced by the very recent studies on involuntary movements carried out by the physician and physiologist William B. Carpenter (1813–1885). In the final paragraphs, Carpenter pointed out that “muscular movement” could be elicited and detected independently of the subject’s conscious influence. This opened the possibility that unconscious action and expectation played a much greater role in everyday life than was usually thought: “the anticipation of a given result being the stimulus which directly and involuntary prompts the muscular movements that produce it [the result]” (Carpenter 1852, 153). Carpenter’s findings resonated with Faraday’s own intuitions as a self-educated experimentalist: developing a sound judgment in scientific and daily matters alike depends on one’s commitment to a life-long education of one’s faculties, just as reaching a “moderate facility” in playing a musical instrument depends on long hours of practice (Faraday [1854] 1859, 491). In time Carpenter would take up Faraday’s experiment along with his insistence on education in the historical and scientific examination of mesmerism and spiritualism (Carpenter 1877).⁶

Faraday was convinced that the table moved by mechanical force, impressed upon it by unaware participants. He thus proceeded to devise an instrument (Fig. 6.1) to check whether the table moved first and the hands followed, as declared by the séance participants, or whether the opposite was true. The ingenuity and simplicity of Faraday’s instrument capitalizes on his early years of apprenticeship as a book binder, as the description below illustrates.

The experiment consisted in interposing a “bundle” of four or five cardboard sheets between the table’s surface and the hands of the participants. Pellets of wax and turpentine kept the bundle together. The “cementum” between the cardboard sheets was “strong enough to offer considerable resistance to mechanical motion, and also to retain the cards in any new position which they might acquire, – and yet weak enough to give way slowly to a continued force” (Faraday 1853b, 802). Faraday marked the position of each cardboard piece and arranged the pile in such a way that the marks would face down. He topped everything with a larger piece of cardboard to disguise the underlying structure, and put the pile on a piece of sandpaper to ensure it would not slide on the table’s surface. After the table’s first hop he examined the pile, and the way the cardboard pieces had been displaced showed the hands had exerted a force first, and the table then moved accordingly. He repeated the observations and found that the carboard showed signs of experiencing mechanical force even when the table did not move at all.

The first part of the experiment showed that the participants in the séance exerted mechanical force upon the table’s surface. From their reports, however, they appeared utterly unaware of doing so, and believed that they felt pressure coming from the table to their hands. Interposing different materials between their hands and the table did not alter the participants’ “effectiveness” in any way; would awareness of their involuntary action change the séance’s outcome? To show participants whether they were applying a force and, if so, in what direction, Faraday built an indicator. It consisted in a piece of paper connected to the bundle of sliding cardboards under the participant’s hands, lifted from the table’s surface by a pin. The pin acted as the fulcrum of a lever, with the shorter arm near the participant’s hands and the longer arm showing the direction of any force applied to the table by the hands, like an index. The party assembled around the table instantly became less “effective”:

The effect was never carried far enough to move the table, for the motion of the index corrected the judgment of the experimenter, who became aware that, inadvertently, a side force had been exerted. […] now that the index was there, witnessing to the eye, and through it to the mind, of the table turner, not the slightest tendency to motion either of the card or of the table occurred. (Faraday 1853b, 803)

Without falling into the trap of ridiculing his audience for their beliefs, Faraday took this opportunity to make a more general point on the role of instruments in enabling reliable observation. He did not criticize the senses as a fallible source of knowledge; rather, he emphasized that they cannot be reliable if unaided by some instrument. In this case, the instrument acts as a control for the very actions séance participants believe they are performing (or not performing). Called “index,” “indicator,” and “instructor,” Faraday’s paper strip allowed participants to perform a task, such as pressing downwards, in a reliable manner. The task’s apparent simplicity probably prevented people from thinking about the need for a control, but Faraday’s experiments had shown that pressing “directly downward” was not an easy task at all. As he clearly stated in his initial remarks to the Times:

I think the apparatus I have described may be useful to many who really wish to know the truth of nature […]. Persons do not know how difficult it is to press directly downward – or in any given direction against a fixed obstacle: or even to know only whether they are doing so or not; unless they have some indicator, which, by visible motion or otherwise, shall instruct them[.] (Faraday 1853a, 390-1; emphasis in original)

Faraday checked the working of the indicator when participants were prevented from seeing it and observed that it would stop moving as soon as the participants were made aware of it. The indicator’s role had a pedagogical as well as a scientific role for Faraday. As a self-educated scientist, he was always interested in methods to improve or educate the mind, as his famous 1854 lecture testifies. In his letter to the Times, Faraday insisted on the power of instruments in correcting observations while at the same time educating the observer:

[…] the most valuable effect of this test apparatus (which was afterwards made more perfect and independent of the table) is the corrective power it possesses over the mind of the table turner. As soon as the index is placed before the most earnest, and they perceive – as in my presence they have always done – that it tells truly whether they are pressing downwards only or obliquely, then all effects of table turning cease, even though the parties persevere, earnestly desiring motion, till they become weary and worn out. No prompting or checking of the hands is needed – the power is gone; and this only because the parties are made conscious of what they are really doing mechanically, and so are unable unwittingly to deceive themselves. (Faraday 1853a, 385, my emphasis)

Faraday’s intervention aimed at showing that, while table turning was a real phenomenon, its causes were not necessarily immaterial in nature. Moreover, it showed that even with the best intentions a mind unaided by some “index” may be deceived. His inquiry did not stop either popular or expert interest in the matter, however, and some researchers continued both to expose fraud and to legitimize psychical phenomena as genuine manifestations of spiritual entities or spiritual forces.

Finally, it is important to note that Faraday’s own efforts to mitigate the “table moving craze that swept England around 1853” (James 1996, xxx) were grounded as much in religious concerns as in broader educational and methodological ones.⁷ While the bulk of his correspondence on table-turning was destroyed (according to his wish), we can glimpse his attitude toward the phenomenon in a letter to Caroline Deacon of 23 July 1853 – which he wrote after publishing the results from his table-turning experiment:

…the world is running mad after the strangest imaginations that can enter the human mind. I have been shocked at the flood of impious & irrational matter which has rolled before me in one form or another since I wrote my [T]imes letter and am more than ever glad that as a natural philosopher I have borne my testimony to the cause of common sense & sobriety […].

(Faraday [1853d] 1996, 538–39)

Deacon (née Reid, 1816–1890) was a niece of Faraday’s wife, Sarah, and the Faradays corresponded with her often. Faraday’s experimental refutation of table moving caused a great stir among “common sense” scientists and spiritualists alike, and it is a pity that his replies are now lost. On the one hand we must recognize, as Frank James certainly does, that Faraday’s identification of table-moving phenomena as “impious” helped motivate him to examine them and try to dispel, with the help of “common sense and sobriety,” the lure of such “imaginations.” On the other hand, however, Faraday believed in the broader educational value of properly conducted experiments, which he thought trained sound judgment. Those epistemic values, while on a continuum with Faraday’s religious values, can still be distinguished from them, and Faraday himself argued for them independently. In the end, his religious motivations were only partly responsible for the development of the specific technology of control that he employed to analyse the phenomenon of table turning.

6.3 Controlling the Medium and Communicating with Spirits: Robert Hare’s Apparatuses

Among the scientists originally praising Faraday’s 1853 experiment there was the American chemist Robert Hare (1781–1858). Dubbed “the foremost chemist of his generation” (Kneeland 2008, 245), Hare was famous in his day for inventing the “oxy-hydrogen blow pipe,” a forerunner of today’s welding torch. He also contributed to funding the Society for the Advancement of American Philosophy in 1848 (Tymn 2021). Hare had seen Faraday’s public lecture in London in 1841, and he occasionally wrote about Faraday’s scientific views, on subjects such as electricity and “the nature of matter.”⁸ In 1853 he published a letter in the Philadelphia Inquirer, denying the possibility of table-turning phenomena. He alluded to self-deception as the only possible source of the motion, and paraphrased Faraday’s original conclusion:

I am of the opinion that it is utterly impossible for six or eight, or any number of persons, seated around a table, to produce an electrical current. Moreover, I am confident that if by any adequate means an electrical current were created, however forcible, it could not be productive of table turning. […] The only subject for inquiry, was how people could so deceive themselves as to suppose that what they really moved, moved them. (Hare [1853] 1855, 35; my emphasis)

Hare concluded his letter with an explicit endorsement of Faraday’s experiment, to which he appended a “moral” of his own:

I recommend to your attention […] Faraday’s observations and experiments […]. I entirely concur in the conclusions of that distinguished experimental expounder of Nature’s riddles. A moral may be drawn from this susceptibility of self-deception. In our moral conduct, as in our physical movements, we sometimes take the effect for the cause, and blame others for that which has originated in ourselves. (Hare 1855, 36; my emphasis)

In line with Faraday’s own views, Hare ultimately blamed some inherent “susceptibility of self-deception” for the blunder; however, he quicky turned this psychological insight into a moral maxim offering no means to correct for our tendency to judge wrongly.

Two years later, in his Experimental Investigations on Spirit Manifestation (1855), Hare reprinted his 1853 Inquirer letter with a response that allegedly moved him to investigate the matter further. The writer of the response – most likely the telescope-maker Amasa Holcomb⁹ – claimed to have witnessed table-turning and related phenomena and then titillated Hare’s curiosity with the prospect of a great scientific discovery:

I cannot in this case doubt the evidence of my senses. I have seen the tables move, and heard tunes beat on them, when no person was within several feet of them. This fact is proof positive that the force or power is not muscular. […] If these things can be accounted for on scientific principles, would it not be a great acquisition to science, to discover what those principles are? (Letter to Hare, in Hare 1855, 37)

While Holcomb supported his claims with the authority of first-person testimony, Hare rose to the challenge of accounting for spirit manifestations “on scientific principles.” In his 1855 Experimental Investigations on Sprit Manifestation (1855) he presents himself as staunch empiricist eventually converted to spiritualism, implicitly inviting the reader on a journey from incredulity to belief. Indeed, Hare had a strong interest in the possibility of spiritualism. At a personal level, he had lost many close family members, including his father, a brother, a sister, and numerous children. Further, he believed that something bigger than himself was at stake in the matter: namely, the possibility of a Christian faith in the modern, scientific world. Hare sincerely believed that demonstrating the existence of psychical forces and spirit communication was crucial to the belief in heaven and in the immortality of the soul. As he wrote in a letter to Silliman, “the single hope for Christianity lay[s] in the verification of spiritualistic evidence; arguments based on the ‘internal evidence’ of Christianity could not survive in the 19th Century” (Hare to Silliman, rough draft, APS; in Moore 1972, 494, footnote 68). Ironically, religion was also a primary concern for Faraday, who opposed spiritualism because he thought it was dangerous for the Christian faith and for thorough scientific thinking.

In the following I illustrate the control strategies, such as the general design and plan, and the control practices, such as concrete actions, that Hare devised to investigate communication with spirits. As he narrates, after his letter “corroborating the inferences of Faraday, […] in obedience to solicitations already cited, [I] consented to visit circles in which spiritual manifestations were alleged to be made” (Hare 1833, 38). There he witnessed some supernatural phenomena of striking personal appeal – the medium gave voice to his own deceased father – but still he would not believe until properly testing the phenomena.

Hare’s chief concern was to safeguard his experiments from the medium’s potential fraud. In a retrospective remark he admitted:

It must be manifest that the greatest difficulty which I had to overcome during the investigation of which the preceding pages give a history, arose from the necessity of making every observation under such circumstances as to show that I was not deceived by the media. (Hare 1855, 54)

Controlling for the possibility that media might deceive was therefore the chief concern behind the construction of his instruments:

Subsequently, I contrived an apparatus which, if spirits were actually concerned in the phenomena, would enable them to manifest their physical and intellectual power independently of control by any medium. (Hare 1858, 40; my emphasis)

Hare actually devised many different apparatuses for the purpose, but they all fall in one of two categories: they are either testing instruments, aiming to prove the reality of communication with spirits by controlling the medium’s actions (Figs. 6.2 and 6.3); or they are personal instruments, aiming to enable anyone to communicate easily with the spirits without the need of a medium or of a spiritual circle (Fig. 6.4). When Hare says that he is performing “tests” with the latter ones, he is already presupposing that communication with spirits is a genuine phenomenon. Although all instruments were indifferently called “spiritoscopes,” the practices of “control” they instantiated were very different.

Fig. 6.2

The instrument that led to Hare’s “conversion.” [Plate I from Hare’s book]

Fig. 6.3

Another testing instrument. Faraday’s lesson is visible in the little board on casters interposed between the medium’s hands and the table’s surface. [Plate II from Hare’s book]

Fig. 6.4

Hare’s spiritoscopes designed for “incipient mediumship,” the one on the right (labelled “Fig. 2” in the original picture) being recommended for beginners. [Plate IV from Hare’s book]

The relevance of apparatuses of the first type should not be underestimated. Although in the body of the text Hare seems to attribute at least part of his conversion to a persuasive manifestation of his father’s spirit, the caption beneath Fig. 6.2 reads: “Engraving and description of the apparatus, which, being contrived for the purpose of determining whether the manifestations attributed to spirits could be made without mortal aid, by deciding the question affirmatively, led to the author’s conversion” (Hare 1855, Plate 1). As seen above, the instrument’s purpose was to control for the medium’s possible manipulation of the manifestations during the séance. It is therefore also partially to the instrument and to its alleged controlling power that Hare attributed his change of feeling on the matter.

Hare described the instrument briefly next to the plate’s reproduction, and then at length in the text:

Two weights were provided – one of about 8 pounds, the other about 2 pounds. These were attached one to each end of a cord wound about the pulley, and placed upon the floor immediately under it. Upon the table a screen of sheet zinc was fastened, behind which the medium was to be seated, so that she could not see the letters on the disk. A stationary vertical wire, attached to the axle, served for an index. On tilting the table, the cord would be unwound from the pulley on the side of the larger weight, being wound up simultaneously to an equivalent extent on the side of the small weight, causing the pully and disk to rotate about the axle. […] Of course, any person actuating the table and seeing the letters, could cause the disk so to rotate as to bring any letter upon the index; but should the letters be concealed from the operator, no letter required could be brought under the index at will. (Hare 1855, 40)

As it appears, Hare took many precautions to prevent that the medium may tilt the table and thereby choose which letters would come under the disk’s indicator; however, in spite of his awareness of studies on the ability of certain mediums to answer correctly to questions whenever anyone in the room happened to know the right answer, Hare did not engage in any practice aiming to control for the possibility of unconscious cueing.¹⁰ Hare’s strategy in addressing this and related objections was to report cases in which something completely unexpected happened. For example, the spirit of a friend would manifested himself when he was waiting for his sister’s, or he would learn something that he did not know before. However, he kept devising more controls to prevent mediums form (voluntarily or involuntary) producing effects with physical rather than psychical means.

In designing his second testing instrument (Fig. 6.3), Hare took into account Faraday’s concern about the motion of tables by mechanical force from unaware participants. To prevent such interferences, he had the medium rest her hands on a small wooden board, separated from the table’s surface by brass balls. This way, involuntary pressure sideways would make only the upper board slide sideways on the ball, with no chance to take the table with it. With a few exceptions, Hare’s instruments did not prevent tables from moving. In his eyes, this result was proof of the reality of spirits and of their ability to manifest themselves.

Once the spirits had passed the “test” of carrying their message to the rotating disk under the strictly controlled conditions provided by the instruments described (Figs. 6.2 and 6.3), they could have an easier time communicating with the living though instruments built for the purpose (Fig. 6.4). These were sorts of miniature tables on wheels, which could be operated by a single person alone. While the mechanism for one them (on the right in Fig. 6.4) was similar to that employed for the testing instrument of Plate 2 (Fig. 6.3), its functioning was allegedly much easier, so that even an “incipient” medium could achieve some effective communication. As Hare reported, “This instrument is preferred by the spirits, and is easier for the feeble medium to employ effectively. I cannot avail myself of Fig. 1 [on the left in Fig. 6.4]; through Fig. 2 [on the right in Fig. 6.4] I have had some interesting tests” (Hare 1855, Plate IV).

As Hare developed mediumship powers, the criteria for control underwent a subtle but essential change. Hare declared that he no longer needed the kind of control provided by his first two instruments to vouch for the phenomena’s reliability; instead, the manifestations’ trustworthiness depended only on his on his own good faith and “character”:

But having latterly acquired the powers of a medium in a sufficient degree to the interchange of ideas with my spirit friends, I am no longer under the necessity of defending media from the charge of falsehood and deception. It is now my own character only that can be in question. (Hare 1855, 54)

Hare rejected with various anecdotes the possibility that he may be deceiving himself, either though self-suggestion, involuntary movements, or the like. Perhaps the best anecdote in his own eyes – he recounted it three times in his 1855 essay (Hare 1855, 32–33, 52–54, 172) – is the following:

The fact that my spirit sister undertook at one o’clock, on the 3rd of July, 1855, to convey from the Atlantic Hotel, Cape May Island, a message to Mrs. Gourlay, No. 278 North Tenth street, Philadelphia, requesting that she would induce Dr. Gourlay to go to the Philadelphia bank to ascertain the time when a note would be due, and report to me at half-past three o’clock; that she did report at the appointed time; and that on my return to Philadelphia, Mrs. Gourlay alleged herself to have received the message, and that her husband and brother went to the bank in consequence. With the idea received by the latter, my sister’s report coincided agreeably to his statement to me. All this proves that a spirit must have officiated, as nothing else can explain the transaction. (Hare 1855, 54)

In this “spiritual messaging” between himself and a sensitive friend, his sister’s spirit acted as messenger going back and forth between them. Here Hare shifted entirely from the domain of experimentation to the domain of testimony; the “controls” offered include (1) accurate descriptions of the event(s), including time, place, and names of the people involved, and (2) a profession of the witness(es)’ integrity.

6.4 Controlling Telepathy Experimentally and Through Testimony: Edmund Gurney’s Program

Experiment was the first but by no means the only method for establishing the reality of psychical phenomena. Such phenomena were indeed hard to observe under experimental conditions common to “any other physical investigation” (Faraday 1853b, 801), and even when they occurred, the risk that they would be exposed as fraud remained high. Eusapia Palladino (1854–1918), one of history’s most celebrated mediums, cleverly admitted the allegation of fraud on psychical grounds: a medium naturally recurs to involuntary movements to “help” the manifestation of the spirit, which would otherwise require too much of her own psychical strength. She then put the ball back in the researchers’ court by asking for stricter controls to prevent her from cheating (Blondel 2002, 157–58).

In this and the following section, I examine other strategies of control researchers used to capture psychical phenomena, focusing in particular on Edmund Gurney’s (1847–1888). Before becoming interested in psychical phenomena, Gurney studied medicine and physiology at Cambridge and published a book on music theory (On the Power of Music, 1880).¹¹ He belonged to Sidgwick’s circle and was a founding member of the Society for Psychical Research (SPR). Gurney chose both (1) to elaborate new forms of control for experiments in psychical topics (Sect. 6.4) and (2) to cast inquiry in psychical phenomena as a historical rather than experimental endeavour (Sect. 6.5).

One of the main aims of writing a “natural history” – a supernatural history, in fact – of psychical phenomena was to reclaim them from the domain of experimental psychology, and therefore to rescue them from their dismissal as the product of involuntary motions by psychologists such as Carpenter. Indeed, Faraday’s fame ensured a wide diffusion of his 1853 experiment; that fame had also sanctioned Carpenter’s authority on the matter and, by extension, the authority of experimental psychology and of its methods of inquiry. Carpenter’s further research on the topic eventually appeared as a book in 1877. This book was Gurney’s point of departure for criticizing experimental psychologists’ authority over psychical research.

Gurney explicitly challenged both Faraday and Carpenter’s conclusions, claiming that (1) they were controlling ordinary experience, without attempting a genuine investigation of extraordinary phenomena, and (2) that, more generally, having acquired an expertise in a certain type of laboratory work did not make them experts in situations where the control strategies developed for the physical sciences did not apply. In the programmatic writing “On the Nature of Evidence in Matters Extraordinary” (1884), Gurney described Faraday’s experiment as an ingenious study in the field of unconscious movements, which however did not investigate “extraordinary matters” such as mind-to-mind communication, or what was later to be called “thought-transference” or “telepathy” (Gurney 1884, 478). Moreover, Gurney dismissed Carpenter’s account as based on “confused” notions of “scientific experts” and the “educated public.” Rejecting these notions was part and parcel of Gurney’s own claim to expertise and to the legitimization of his method of inquiry (Gurney 1884, 477).¹²

If psychical phenomena were not amenable to traditional forms of experiment, then experimental psychologists and physicists were not better qualified than any other honest investigator in adjudicating the claims of psychical research. In the 1884 essay, Gurney thus proposed a radical change of method, from laboratory work to “historical” research in the field:

Where phenomena cannot be commanded at will (as is the case in some of the more striking departments of our research), the work of investigating them must consist, not in origination, but in the collecting, sifting, and bringing into due light and order, of experiments which Nature has from time to time given ready-made. And the due estimation of these depends, in the broadest sense, on the estimation of testimony; on what may be called historical, as opposed to experimental, methods of enquiry […]. (Gurney 1884, 482)

Indeed, if psychical phenomena could not be produced and re-produced at will, what was the advantage of a laboratory setting?¹³ Especially given the many difficulties encountered in ensuring that manifestations from spirit circles were not artifacts of suggestion, involuntary movements, or trickery, collecting and analyzing testimonies of spontaneous apparitions could seem a safer and more productive alternative. Yet, history is not a straightforward matter, and “collecting, sifting, and bringing to light” those cases of spontaneous apparitions was no small challenge. It required a strategy to control testimonies – to check their reliability and to select among them accordingly. It also required familiarity with probability theory, since a testimony’s truth was to be assessed on the prior probability that a given fact may be false. In addition, the approach required a particular understanding of the logic of induction so that, according to Gurney, the argument for psychical facts would not be considered “as weak as its weakest link.” Instead, it must be allowed to accumulate every small piece of evidence into a collectively more robust construction (more on this in Sect. 6.5).

Eventually the SPR adopted a mixed-method approach, which integrated a revised experimental strategy with the historical research advocated by Gurney in 1884. In the two-volume work Phantasms of the Living, published in 1886 by Gurney, Frank Myers, and Frederic Podmore, the first chapters report the authors’ experiments in thought-transference, which occurred with mediums in 1882 and 1883.¹⁴ In the Introduction, the authors declare that “Experiment proves that telepathy […] is a fact in nature” (Gurney et al. 1886, lxv, emphasis in original). The bulk of the work, however, and the part most interesting to critics, consisted in testimonies of veridical apparitions and verified cases of mind-to-mind communication. The authors defined these phenomena as “the supersensory transference of thoughts and feelings from one mind to another,” and defined “supersensory” as “independent of the recognised channels of sense” (Gurney, Myers, and Podmore 1886, e, note 1). The called them “telepathic” phenomena and added that, although they did not occur through ordinary sense channels, they could still be “analogous” to ordinary perception.

Neither Gurney’s criticism for experimental methods nor his program of writing a sort of supernatural history resulted in excluding experiment. In the Phantasms Gurney reintroduced experiments but redefined them around his subject matter: they should not be subjected to the same criteria as experiments in experimental psychology. Moreover, psychical experiments should be taken in conjunction with the historical research in spontaneous manifestations.¹⁵ In the following, I examine the structure of experiment as reported in the first chapters of the Phantasms and the criteria introduced to control for the results. In Sect. 6.5 I look in greater detail at Gurney’s implementation of the historical method and at Charles S. Peirce’s criticism of it.

As the authors admitted, the structure and method for the telepathic experiment came to the SPR as a development of the “willing game,” a Victorian parlor game that had become popular on both sides of the Atlantic. It consisted in a sort of telepathic hide and seek, where a “percipient” would wait outside a room while the remaining players hid an object or chose an action they might “will” the percipient to perform. Upon entering the room, the percipient had to find the object or perform the action, in each case following an inclination mysteriously communicated either by physical contact from the other “willers,” or by sheer willpower (Gurney et al. 1886, 14). The game modeled the type of phenomenon the SPR wanted to reproduce, but much was needed for “controls.” The first degree of control amounted simply to watching one’s own actions and words:

…when the experiments are carried on in a limited circle of persons known to each other, and amenable to scientific control, it is not hard for those engaged to set a watch on their own and each other’s lips; and questions and comments can be entirely forbidden. (Gurney et al. 1886, 18; my emphasis)

The idea was that agents gathered together would be able to communicate telepathically, by willing that the percipient receive a certain message, with no exterior cues. At least in this phase the researchers did not entertain the possibility of unconscious cueing. The notion of “scientific control” remained vague, at best hinting at committed and intentional observation of certain behavior norms. Since so much of “control” was part of the observer’s experience, Gurney recognized that “it would be rash […] to represent as crucial any apparent transferences of thought between persons not absolutely separated” (1886, 19). He therefore listed the “conditions of a crucial result” from the first-person observer’s perspective:

The conditions of a crucial result, for one’s own mind, are either (1) that the agent or the percipient shall be oneself; or (2) that the agent or percipient shall be someone whose experience, as recorded by himself, is indistinguishable in certainty from one’s own; or (3) that there shall be several agent or percipients, in the case of each of whom the improbability of deceit, or of such imbecility as would take the place of deceit, is so great that the combination of improbabilities amounts to a moral impossibility. The third mode of attaining conviction is the most practically important. (Gurney et al. 1886, 19; my emphasis)

The investigators conceived their inquiry as “experimental,” because it involved the experimenter intervening on a “perceiving” subject. But the method for controlling results was much closer to that of a historical investigation than a physical one, because the experimenter’s honest intention could only be measured against the honest intentions of his peers. The need to multiply such experiences, or the request that “several agents or percipients” be present, seemed the most important form of (implicit?) control for establishing the reality of telepathic phenomena. Even these conditions were not easy to achieve, however. Because the observers were both “controls” and crucial elements of the experiment’s setup, and because “percipient” subjects were very sensitive to their environment, multiplying observations was likely to disrupt the phenomena. Reverend Creery, who, after some very successful sessions of the “willing game” with his daughters, had contacted the SPR and embarked on a series of “thought-transference” and telepathy experiments, mentioned the influence of the particular individuals involved on the success of the experiment:

We soon found that a great deal depended on the steadiness with which the ideas were kept before the minds of “the thinkers,” and upon the energy with which they willed the ideas to pass. Our worst experiments […] have invariably been when the company was dull and undemonstrative… (Gurney et al. 1886, 21)

Gurney’s own testimony echoed this statement regarding the SPR’s experiments with the Creery family:

Questions of mood, of goodwill, of familiarity, may hold the same place in psychical investigation as questions of temperature in a physical laboratory; and till this is fully realised, it will not be easy to multiply testimony to the extent that we should desire. (Gurney et al. 1886, 30)

In the case of the Creery family, the young age of the daughters further discouraged the experimenters from introducing stricter “scientific” controls. As a precaution against cueing, the girls would wait in another room while the object to be fetched was “willed” – and that was the extent of the external controls employed. Time and again, Gurney et al. return to the crucial tension between the desire to implement stricter degrees of “control” and the risk that such controls may contradict the very nature of the phenomena to be observed. For instance, in commenting on experiments with other subjects, they wrote:

It is the “delicate psychological conditions” […] that are in danger of being ignored, just because they cannot be measured and handled. The man who first hears of thought-transference very naturally imagines that, if it is a reality, it ought to be demonstrated to him at a moment’s notice. He forgets that the experiment being essentially a mental one, his own presence – so far as he has a mind – may be a factor in it; that he is demanding that a delicate weighing operation shall be carried out, while he himself, a person of unknown weight, sits judicially in one of the scales. After a time he will learn to allow for the conditions of his instruments, and will not expect in the operations of an obscure vital influence the rigorous certainty of a chemical reaction. (Gurney et al. 1886, 51; my emphasis)

While apparently contrasting the reliability of experiments in chemistry to the unpredictable psychical phenomena, Gurney was in fact individuating in the investigation of the latter difficulties which would ring familiar to readers conversant with other better-established disciplines, such as physics. For example, in Lord Rayleigh’s work on the determination of the Ohm (Rayleigh 1881, 1882) the experimenters had to adopt radical measures to control for interference, including conducting observations at night to prevent vibrations from traffic on nearby streets.¹⁶ The many experiments on “Brownian motion” – i.e., the apparently spontaneous motion of matter particles suspended in a fluid – also illustrated the experimenters’ awareness of the almost infinite ways in which disturbing and confounding factors could compromise an experiment (Coko, this volume). As Graeme J. N. Gooday notes, “Victorian instruments were not habitually used in anything like the disturbance-free convenience of the purpose-built late twentieth-century research laboratory” (Gooday 1997, 411). How could anyone, then, expect that experiments with psychical forces would be different? If “mood” and “temperament” in psychical research were comparable to the “temperature” in a physics laboratory, the “percipient” herself was then likened to a “delicate instrument.” This analogy was common in the psychical literature of the time, and one which could be adopted by the medium herself.¹⁷

In short, while psychical researchers wished to distinguish their investigation from those in the physical sciences – and particularly from the limitations of Faraday and Carpenter – they still upheld these disciplines’ ideal of a controlled experiment, which should ensure trustworthiness in the study of psychical phenomena. For one, the possibility of environmental disturbances in the environment did not automatically disqualify the observations reported. Any observation could be registered within an interval of confidence, and indeed part of Gurney et al.’s argument for telepathy was based on a mixture of statistical and probabilistic reasoning.¹⁸ Moreover, because the manifestation of psychical phenomena was difficult to control, they directed their control efforts toward experimental design and setup. Thus Mr. Malcolm Guthrie, the owner of a textile factory in Liverpool, reported to the SPR his experiments on thought-transference with some of his employees. He emphasized his ability to control every aspect of the experiment, from its design to its realization:

I have had the advantage of studying a series of experiments ab ovo [i.e., from the very beginning]. […] The experiments have all been devised and conducted by myself and Mr. Birchall, without any previous intimation of their nature, and could not possibly have been foreseen. In fact they have been to the young ladies a succession of surprises. (Gurney et al. 1886, 36–37, emphasis in original)

Guthrie concluded his description boasting that no series of thought-transference experiments had ever been as satisfactorily controlled as his: “No set of experiments of similar nature has ever been more completely known from its origin, or more completely under the control of the scientific observer” (Gurney et al. 1886, 37; my emphasis).

Guthrie’s experiments consisted in having the “observer” fixate his attention on a diagram or simple picture, while the subject, sitting in a separate room, would attempt to draw it. Some of the results were reproduced in Gurney et al.’s Phantasms (Figs. 6.5 and 6.6). These experiments were soon repeated by Dr. Oliver J. Lodge, “professor of physics in University College, Liverpool.” Lodge also spoke about the impact of control on one’s confidence in the results of the experiments:

…to the best of my scientific belief no collusion or trickery was possible under the varied circumstances of the experiments. […] When one has the control of the circumstances, can change them at will and arrange one’s own experiments, one gradually acquires a belief in the phenomena observed quite comparable to that induced by the repetition of ordinary physical experiments. (Lodge, in Gurney et al. 1886, 49; my emphasis)

Indeed, while the kind of mind-to-mind communication investigated by the SPR was supposed to happen “outside the ken of senses,” the requirements of control in the experimental setting strove to make the phenomena as ordinary as possible. This attitude rejected the thrills of ghost-stories to take a “cautious” and methodical approach to the matter, and extended from the experimental investigation to the collection and analysis of cases of “spontaneous” telepathy. As Shane McCorristine writes, the SPR embraced “quantitative, rather than qualitative methodology of reducing ghosts to statistics, as opposed to sensational experiences” (2010, 124). In the eyes of Gurney, Myers, and Podmore, experiment demonstrated the “fact” of telepathy but this evidence had to be corroborated by a patient collection and verification of testimonies of ordinary apparitions, or “veridical hallucinations.” These were manifestations whose content could be successfully cross-checked against historical facts. Such testimonies would become even more important after 1888, when Gurney published a Note admitting that the Creery sisters had been using a code to communicate in various tests (McCorristine 2010, 171).

Fig. 6.5

Attempts at mental communication. (Selected from Phantasms)

Fig. 6.6

Attempts at mental communication. (Selected from Phantasms)

6.5 Testimony and Its Tests: Gurney and Charles S. Peirce

If experiment, according to Gurney et al., proved the reality of telepathic phenomena, historical investigation into spontaneous telepathic manifestations played an important complementary role in establishing telepathy as a natural phenomenon, although somehow happening through other channels than those of ordinary sense-perception. Indeed, spontaneous and experimental cases of telepathy were considered two distinct manifestations of the same phenomenon: “The great point which connects many of the more inward impressions of spontaneous telepathy with the experimental cases is this – that what enters the percipient’s mind is the exact reproduction of the agent’s thought at the moment” (Gurney et al. 1886, 232). The recording of “spontaneous” telepathy relied on the collection of testimonies of apparitions, carefully cross-checked by Podmore. Testimony too had a probatory role, as Myers emphasized in the introduction: “Testimony proves that phantasms (impressions, voices, or figures) of persons undergoing some crisis, – especially death, – are perceived by their friends and relatives with a frequency which mere chance cannot explain” (Gurney et al. 1886, f; my emphasis).

In desiring to study psychical phenomena in a controlled manner, the SPR moved away from discourse on “spirits” and angelic intelligences to focus on mundane communication of thoughts or impressions – which ought to happen strictly between living persons. “Death” was reconceptualized as a “crisis,” an episode (if perhaps the last one) of someone’s life. “Our subject is phantasms of the living: we seek the conditions of the telepathic impulse on the hither side of the dividing line, in the closing passage of life; not in that huge negative fact – the apparent cessation or absence of life – on which the common idea of death and of its momentous importance is based” (Gurney et al. 1886, 230). The expression “of the living” was intentionally ambiguous, suggesting that the appearances both came from and represented (still) living people. This positivist setup left some room, however, for radically reconceptualizing the notion of the self as involving “a more fundamental unity, which finds in what we call life very imperfect conditions of manifestation” (1886, 231). Accordingly, the “individuality” that each of us regards as our “self” would be a “partial emergence” of this deeper “unity,” and it is to this deeper level that “telepathic” manifestations may be tied:

And this hypothesis [i.e., the hypothesis of a deeper self] would readily embrace and explain the special telepathic fact in question; while itself drawing from that fact a fresh support. By its aid we can at once picture to ourselves how it should be that the near approach of death is a condition exceptionally favourable to telepathic action, even though vital faculties seem all but withdrawn, and the familiar self has lapsed to the very threshold of consciousness. For to the hidden and completer self the imminence of the great change may be apparent in its full and unique impressiveness; nay, death itself may be recognised, for aught we can tell, not as a cessation but as a liberation of energy. (1886, 231, my emphasis)

The deep-self hypothesis might explain the perplexing fact that most of, if not all, the reported “phantasms” belonged to someone near death. However, the authors never explicitly argued for it, since the declared purpose of the Phantasms was to “bring the evidence to light” before arguing about possible explanations for it. As the authors declared, “we may contrast telepathy, not only with the comparatively modern superstition of witchcraft, but with phenomena of much older and wider acceptance – the alleged apparitions of the dead” (Gurney et al. 1886, 121). Yet the authors had to introduce further conditions for deciding when to accept a testimony. As they put it: “The evidence for telepathy has a certain type and structure of its own, and we must realise what this is, in order to know where to look for the weak points. What, then, are the essential elements of a typical telepathic phenomenon?” (Gurney et al. 1886, 131).

Let us examine these elements. First, Gurney et al. insisted on a “sober” and unimaginative nature of their witnesses: “a very large number of our first-hand witnesses are educated and intelligent persons, whose sobriety of judgment has never been called in question,” 1886, 120–21). Second, they wished to ensure that news of a person’s death did not precede their apparition: “one of the points to which we have, throughout our inquiry, attached the highest value, is the proof that evidence of the percipient’s experience was in existence prior to the receipt of the news of the agent’s condition” (1886, 134). However, information about times of death and apparitions was not easy to get. In order not to discard too many testimonies, the authors agreed on a protocol allowing a 12-h window between a person’s death and their alleged apparition, to accommodate for uncertainty, memory lapses, and time zones. Finally, the percipient’s condition must be taken into account, and testimony from sick, drunk, anxious, or habitually hallucinating subjects had to be rejected.¹⁹ If enough phenomena were found to satisfy these conditions, then telepathy might stand a chance at being investigated as any other natural phenomenon:

Amid all their differences, the cases present one general characteristic – an unusual affection of one person, having no apparent relation to anything outside him except the unusual condition, otherwise unknown to him, of another person. It is this characteristic that gives them the appearance, as I have just said, of a true natural group. (Gurney et al. 1886, 164; my emphasis)

According to Gurney et al., saying that telepathic phenomena constituted a “true natural group” was just another way of stating that they were real phenomena, worthy of further investigation. Their work, while deploring the inevitable loss of evidence on similar cases, aimed to build a repository of that little evidence that still existed and to be a model for further research:

By far the greater part of the telepathic evidence, even of the last twenty years, has undoubtedly perished, for all scientific purposes; we want the account for the next twenty years to be different. But it is only by a decided change in the attitude of the public mind towards the subject that the passing phenomena can be caught and fixed; and it is only by a wider knowledge of what there already is to know that this change can come about. (Gurney et al. 1886, 169)

Phantasms of the Living was written to change attitudes on the matter of psychical research, which the authors hoped would become a respectable topic of inquiry. This change of “attitude of the public mind” hinged on proposing a new object of study – telepathic communication – on which to focus the scientific efforts, but it also offered a new conception of experiment and of the relevance of testimony to establish the reality of the phenomenon at stake. Like his father before him, Charles S. Peirce was asked to act as “control” for the case in question; his task was not to sit in a box with putative mediums, but to read and evaluate the Phantasms.

When Gurney et al.’s work launched, Peirce had just edited a collected volume on logic, to which he contributed the chapter “A Theory of Probable Inference,” containing sections on both statistical and probabilistic reasoning (see Peirce 1883). With Joseph Jastrow he had also just co-authored a paper in experimental psychology that concluded there was no fixed threshold of sensation (Peirce and Jastrow, 1884). Interestingly, the conclusion of his experimental psychology paper linked his results on perception to the telepathy debate of the time:

The general fact [that there is no “least perceptible difference” in sensation] has highly important practical bearings, since it gives new reason for believing that we gather what is passing in one another’s mind in large measure from sensations so faint that we are not fairly aware of having them, and can give no account of how we reach our conclusions about such matters. The insight of females as well as certain “telepathic” phenomena may be explained in this way. Such faint sensations ought to be fully studied by the psychologist and assiduously cultivated by every man. (Peirce and Jastrow 1884, 83, W5, 135, my emphasis)

The scare quotes for “telepathic” show that Peirce in 1884 may not have been convinced of the phenomena’s reality.²⁰ Following Faraday and Carpenter’s example, he approached these enigmatic cases as signs of physiological or psychological processes that would have to be better understood by better knowledge of how our senses work. His experiment did not focus on psychical or telepathic manifestations, but its conclusions allowed Peirce to hypothesize that telepathy too may be understood as an extreme case of perceptual acuity without awareness.

Reading the Phantasms did not change Peirce’s opinion on the nature of “telepathic” phenomena. He had two kinds of objections for Gurney. The first concerned the use of statistics to evaluate the incidence of the phenomena, and the use of probability to estimate the likelihood that a given apparition was indeed a case of telepathic communication and not a hallucination surrounding an untimely death. Peirce’s verdict was blunt:

… these gentlemen, having addressed, as they estimate, a public of only 300,000 persons, claim to have found thirty-one indubitable cases of this kind of coincidence within twelve years. From this, they cipher out some very enormous odds in favor of the hypothesis of ghosts. I shall not cite these numbers, which captivate the ignorant, but which repel thinking men, who know well that no human certitude reaches such figures as trillions, or even billions to one. (Peirce 1887a, W6, 75)

The second objection was specific to the 31 cases the authors presented as “indubitable.” Going case by case, Peirce argued against including each in the collection. He said that “every one of their thirty-one coincidences sins against one or more of the eighteen different conditions to which such an argument must conform to be valid” (Peirce 1887a, W6, 75). These “eighteen conditions” are all variations on the three proposed by Gurney et al.: (1) the status and trustworthiness of the witness, (2) the 12-h window between a person’s death and their apparition, (3) the good physical and mental health of the percipient at the moment of the apparition (and that the percipient was not habitually subject to hallucination). Among the variations on these conditions – introduced first by Gurney et al., although scattered throughout the book – are the requirements that the percipient be “wide awake” at the moment of the apparition; that the apparition be “clearly recognized”; that the subjects not have hallucinations “fortuitously”; that a “supposition of trickery,” if available, trump the telepathic explanation. Witnesses are discounted on grounds of class (“No case should be admitted upon the unsupported and unverified statement of a superstitious, ignorant, and credulous person. And a common sailor or skipper may be assumed to be such a person,” Peirce 1887a, W6, 79), of physical conditions (“intoxicated,” “delirium of fever,” W6, 79), and of sloppiness (“No case can be admitted which rests largely on the testimony of a loose or inaccurate witness,” W6, 80). Moreover, Peirce protested that “where there is only a meagre story told in outline, we are not furnished with any means of judging of the reliability of the witness,” and that in some cases “questions might have been asked which would have brought the matter to a test, and have not been asked” (ibid.). For him, an extended account was particularly necessary since the reader had no other way to examine the information than by the words of the authors. Moreover, if the authors did not provide the information necessary to evaluate each case, they would affect the reader’s confidence in entire project:

After all, the reader, who cannot cross-examine the witnesses, and search out new testimony, must necessarily rely upon Messers. Gurney, Myers, and Podmore having on the whole performed this task well; and we cannot accept any case at all at their hands, unless, as far as we can see, they have proved themselves cautious men, shrewd observers, and severe logicians. (Peirce 1887a, W6, 81)

Peirce circled back to his criticism of the quantitative aspects of the work at the end of his assessment, although again without entering in much detail; his concluding remarks feign some charity on the methodological side but hit at the heart of Gurney et al.’s epistemic aim, which was of establishing telepathic phenomena as scientific facts:

The argument might, certainly, have been constructed more skillfully [sic.]; but I do not think that there is much prospect of establishing any scientific fact on the basis of such a collection as that of the Phantasms of the Living. (Peirce 1887a, W6, 82)

The discussion did not end after Peirce’s report. Gurney responded to Peirce’s assessment (Gurney 1887), Peirce provided a new (and more acrimonious) criticism of the evidence presented in the Phantasms, and this was followed by a last reply from Gurney (1889), who unfortunately died that very year. The rejoinders present more extensive sections dedicated to discussing the data’s statistical significance and the antecedent probability of telepathic manifestations. Both parties rely strongly on some numerical estimates, which however are based on the same qualitative assessment of the received testimonies. Hence, the quantitative elements don’t seem to add a meaningful layer of control over the case at hand, but rather to offer the opportunity for Peirce to definitely reject the possibility of establishing telepathic phenomena as “scientific truths”:

… until telepathic theory of ghost-stories has been rendered far more antecedently probable than it now is, it is useless to try to establish it as a scientific truth by any accumulation of scientific observations. (Peirce 1887b, W6, 142)

Gurney’s final words were a plea to continue the independent and honest examination of the matter, as well as a new argument over the kind of probability used to evaluate the phenomena. Gurney claimed the posterior probability that a series of telepathic hallucinations were all due to coincidence was low, and that consequently the probability they were real phenomena was high. He also argued that Peirce confounded that probability with the prior probability²¹ that a given hallucination would be a case of true telepathic communication and not of mere coincidence or fraud. Eventually, even if Peirce did not accept Gurney’s arguments nor his evidence on telepathy, Gurney won the methodological battle: an opponent of telepathic communication had engaged with the phenomenon in the terms Gurney, Myers, and Podmore had set for it.

6.6 Conclusion

This chapter focused on nineteenth-century discussions of method, experiments, and data collection for psychical phenomena. These cases were either based on experiments or on “spontaneous” manifestations, which, by definition, may happen at any time of day or night and in ordinary, non-controlled settings. Nonetheless, in the context of spontaneous manifestations “controls” came back as standards for respectable testimony and as “historical” cross-examinations of the information. The account presented here is far from exhaustive; its aim is not to present general conclusions on psychical research, but rather to show the value of this field of inquiry for historians and philosophers of science interested in the notion of control. A few points are of particular interest.

First, the word “control” appears in this context (specifically in the work of Gurney, Myers, and Podmore) as an actors’ term, a point missing from most discussions of experiment in this and earlier times (as other chapters in this volume illustrate). Second, Gurney et al. connect issues regarding controlled conditions (or the lack thereof) in psychical research with parallel troubles in physical laboratories. Since they cannot multiply or radically change their “instruments” (i.e., the medium), they corroborate their findings with historical and observational studies and argue for their statistical significance. Third, for both SPR researchers and for Hare, “control” is about controlling the instruments or the experiment’s setting; there is no discussion of “comparison with a control.” Faraday’s experiment did include this element, however, insofar as he observed table-turning with and without an “indicator” showing participants the direction they were actually pressing on the table. Only the table without the indicator could move, which led to Faraday’s conclusion that it is pressure exercised unconsciously by the participants’ hands – and not some spirit or new psychical force – that moves the table.²²

The focus on experimental strategies and controls does not deny important connections between psychical research and spiritualism, and the religious interpretations for these manifestations. As shown in the introduction and throughout the chapter, psychical manifestations could be seen as confirmation for Christianity and for the theory of the soul’s immortality, or as blasphemous and materialistic distortions of the Christian faith. Religion, personal circumstances, and methodological concerns all influenced how prominent scientists engaged the debate. Yet, the ability to justify methodological choices in methodological terms, and the attention paid to the instruments involved in the séances or to the collection and sifting of testimonies cannot be sufficiently explained with recourse to religious and biographic elements only. The very practices in which those scientists and investigators were involved testify to the notion of “science” at play in the second half of the nineteenth century, and looking at those practices more carefully sheds new light on the nineteenth-century equivalents of “control” in scientific research.

For example, both Faraday and Hare conceived methods and strategies to control for phenomena they had a strong religious interest in. But those strategies are no less interesting from an epistemological standpoint because the investigation’s result lay close to the inquirers’ hearts, nor can their differing conclusions be accounted for purely by their different starting points. Methodologically, Hare’s first point of departure from Faraday concerns the phenomena he chooses to control for. For Faraday there was a single, crucial physical manifestation to control, namely the direction of the movement: did it go from the table to the participants’ hands, or was the opposite true? For Hare, the physical manifestations to control for were many and complex ones, involving dials, disks with letters and short phrases written on their circumferences. Motion was no longer enough to prove a spiritual agency; the spirit(s) had to be able to move the table in a specific way in order to select the right letters and deliver a comprehensible message. Hare’s attention to control is even more striking if compared with the apparent lack of it in Holcomb’s letter, which prompted him to look closely at psychical phenomena in the first place. While Holcomb appealed to the testimony of the senses, Hare constructed complex instruments to control for the phenomenon he wished to observe – communication between spiritual entities and living beings.

Gurney and the other members of the SPR attempted to “control” the phenomena by renegotiating the scientific practices deemed adequate to capture them. Thus, Gurney criticized Faraday’s and Carpenter’s experimental approaches and proposed an alternative based on collecting and analyzing “spontaneous” telepathic phenomena, rather than on attempts at producing supernatural effects in the laboratory. Although he did not explicitly advocate for reforming the experimental method in such matters, Phantasms of the Living contains an experimental section, which the authors endorse as at least as authoritative as the historical data contained in the rest of the book. Analyzing these experimental cases shows how the notion of control is articulated in these new settings. The criteria for control are then examined in conjunction with Charles S. Peirce’s criticisms. The controversy between Gurney and Peirce reveals how the battle for the “right” control practice is also an existential battle to affirm (or deny) the reality of telepathic phenomena.

Eventually, control over the setting is both a contingent and a constitutive feature of the knowledge gained in empirical inquiry. What is controlled (for) depends on how the experimenter conceptualizes what is going on (voluntary or involuntary movements, “willing” influences, or “spontaneous” manifestations); once the phenomenon is framed in a certain way, that determines what will need to be controlled. While the cases examined in this chapter do not offer one coherent methodology for investigating psychical phenomena, they offer many examples of designing and applying controls, and these examples help us understand how knowledge is construed in empirical inquiry.