Henry Sidgwick

Henry Sidgwick (1838-1900) was professor of moral philosophy at Trinity College, Cambridge, whose work on ethics continues to be influential. Like many of his contemporaries, Sidgwick wondered whether religious belief is possible in the new scientific age, and this preoccupation stimulated a strong interest in claims of psychic phenomena. He was a co-founder of the Society for Psychical Research in 1882 and was its first president, contributing largely to its organization and also taking part in certain research activities, notably with regard to hallucinations. Sidgwick became quickly convinced of the reality of telepathy and related phenomena, but, unlike some of his colleagues, he remained uncertain whether mediumistic and other phenomena indicated that consciousness survives death.

This article is drawn from an essay by Alan Gauld: ‘Henry Sidgwick, Theism and Psychical Research’, published as a chapter in Henry Sidgwick Happiness and Religion.1 It describes the development of Sidgwick’s interest in psychic phenomena and the key role he played in the founding of psychical research as a scientific endeavor.

Early Life

Henry Sidgwick was born in 1838 into a wealthy family. His father, the Rev William Sidgwick, was a grammar school headmaster. From an early age he showed a strong intellectual curiosity, gifted in mathematics and literature.2 He was educated at Rugby school where he was influenced by a relative, Edward White Benson, a classical scholar who was later ordained a priest and became Archbishop of Canterbury. Sidgwick went on to Trinity College, Cambridge, where Benson had studied; he became an assistant tutor in classics at Trinity, later switching to moral sciences. In 1876 he married Eleanor Balfour, sister of the Tory politician (and later prime minister) Arthur Balfour. In 1883 he was appointed Knightbridge Professor of Moral Philosophy. His book The Methods of Ethics (1874) is a statement in the utilitarian tradition of Jeremy Bentham and James and John Stuart Mill, frequently cited in debates about ethics in the twentieth century.3

Interest in Psi

Sidgwick’s interest in psi research was motivated by religious doubts that plagued him throughout his life, and which he hoped might be settled by empirical proofs of an afterlife.4

At Cambridge Sidgwick joined the Apostles, a debating club, and this encouraged a new scepticism concerning beliefs he had previously taken for granted.  By the 1860s he had largely abandoned any orthodox form of Christian belief, although he still thought of himself as a theist. In 1880 he wrote:

I do not know whether I believe or merely hope that there is a moral order in this universe that we know, a supreme principle of Wisdom and Benevolence, guiding all things to good ends, and to the happiness of the good… All I can say is that no opposed explanation of the origin of the cosmos… seems to me even plausible, and that I cannot accept life on any other terms, or construct a rational system of my own conduct except on the basis of this faith.5

Frederic Myers, his Cambridge friend and close associate in psychical research, recalled asking Sidgwick during a walk in 1871

whether he thought that when Tradition, Intuition, Metaphysic, had failed to solve the riddle of the Universe, there was still a chance that from any actual observable phenomena – ghosts, spirits, whatsoever there might be, – some valid knowledge might be drawn as to a World Unseen. Already, it seemed, he had thought that this was possible; steadily, though in no sanguine fashion, he indicated some last grounds of hope…6

Sidgwick was interested in paranormal phenomena at an early age. At Cambridge he joined the Ghost Society, co-founded by Benson, and took part in informal investigations.  Experimenting with a college friend in 1863 he took part in table turning sessions, where movements and noises occurred that he was certain were not caused by anyone present.7

Sidgwick had been impressed by William Crookes’s findings with regard to the celebrated medium DD Home, with whom he experimented between 1870 and 1874.8  He and Eleanor embarked on  investigations of mediums in the summer of 1874, but the couple saw little genuine phenomena and became disillusioned. However, experiments in thought transference by William Barrrett revived his interest. Barrett and a leading spiritualist, Edmund Dawson Rogers, proposed the formation of a society in which scholars and scientists might join forces with prominent spiritualists to investigate phenomena of which the latter claimed special experience.

Independently, Myers had suggested to Sidgwick that an informal association be set up to look further into these matters. The pair were joined in this endeavor by others in what would become known as the ‘Sidgwick Group’, notably the Tory politician, and later prime minister, Arthur Balfour, physicist Lord Rayleigh, Edmund Gurney, and Walter Leaf, a distinguished classical scholar – all at one time fellows of Trinity – also two of Balfour’s sisters: Eleanor, later Sidgwick’s wife, and Evelyn, Rayleigh’s wife.

The Sidgwick Group subsequently played an important role in the founding of the Society for Psychical Research in London in February 1882, with the goal of investigating the claims of mediumistic and other psychic phenomena.  Sidgwick became its first and longest-serving president, and with his known intellectual qualities and fair-mindedness, along with establishment connections with reputable figures such as Benson and Balfour, provided reassurance that its aims would be serious and responsible.

Sidgwick had, through his involvement in university issues and in women’s education, himself developed political skills helpful in presenting difficult issues and advancing causes that were widely regarded with suspicion. He supported the SPR both in public roles as president and chairman of meetings, and as participant in and organizer of international psychological conferences. Behind the scenes he was involved in activities, committee work, planning the placement of articles in widely-read periodicals, editing the SPR’s Journal and Proceedings (from 1888 to 1897), and in frequent discussions with leading members, not least members of the Sidgwick Group.

In the course of time other interested persons were co-opted into the group on account of their abilities and dedication. They included Sir Oliver Lodge, Richard Hodgson, Frank Podmore, Alice Johnson, Frederic Myers’s brother Arthur, and Margaret Verrall. Sidgwick’s influence on the activities and tone of the SPR was thus pervasive and long outlasted his own lifetime.

Statements About Aims and Methods

In a series of presidential addresses, Sidgwick describes his thinking about how the Society should aim to convince others about its findings. He starts by raising the question of why one should establish a research society at all at this time, and answers that ‘it is a scandal to the enlightened age in which we live’ that dispute as to the reality of the alleged phenomena – of which it is quite impossible to exaggerate the scientific importance, if only a tenth part of them could be shown to be true – should still be continuing. He says, ‘The aim of our Society is to make a sustained and systematic attempt to remove this scandal… without any foregone conclusion as to their nature’.9

Sidgwick also reveals more personal aims by which he and the Sidgwick Group were moved to take up ‘the obscure and perplexing investigation which we call Psychical Research’. Here he speaks of ‘the painful division and conflict’ between the still dominant Christian teachings and the materialist deliverances of modern physiology over the nature and destiny of the soul. He and his friends ‘believed unreservedly in the methods of modern science’ but ‘thought that there was an important body of [relevant] evidence… which modern science had simply left on one side with ignorant contempt’.

This body of evidence they ‘proposed to examine, to the best of [their] ability, according to the rules of scientific method’. And they meant to collect and consider such evidence ’without prejudice or prepossession, giving the fullest and most impartial attention to facts that appear to make against the hypothesis that the evidence at first sight suggested’. Only ‘a rigorous exclusion of… known causes could justify us in regarding as scientifically established the novel agency of mind acting or perceiving apart from the body’. And he thinks that he and his colleagues have introduced the minimum of theory required to cover the facts they regard as established without making ‘assumptions which we regard as unwarrantable’.10

In his fifth address,11 his recommended rules of procedure are ‘the obvious dictates of plain common-sense, assuming our object to be simply that of arriving at the truth’.12 He warns those optimists who believe that we already have facts enough and should proceed to theory-building that they are deceiving themselves. For, as he says in his first address 

we must not expect any decisive effect in the direction at which we primarily aim, on the common-sense of mankind, from any single piece of evidence, however complete it has been made. Scientific incredulity has been so long in growing, and has so many and so strong roots, that we shall only kill it… by burying it alive under a heap of facts’13  He returns to this requirement again and again, and remarks in his fifth address that if facts of high quality cease to be obtained, then as time goes on ‘the absence of such evidence will constitute an argument of continually increasing strength against our conclusions’.14

Commitment to the requirements of orthodox science as regards accumulating ‘high quality’ facts, giving due weight to criticism, making use of appropriate methods, and confining oneself to minimum hypotheses, does not mean losing sight of common-sense when one is confronted with silly counter-explanations, even when these are put forward by scientists. The fact (for instance) that some weakly evidenced cases of alleged paranormal happenings are susceptible of obvious normal explanations cannot, he says, be legitimately used to discredit all cases of that type irrespective of quality of evidence. Those who demand that evidence (for instance, for thought-transference) should be repeatable at will forget that, if there is such a function, it will prima facie depend 

on the establishment of a certain relation between the nervous systems of the agent and percipient respectively; and as the conditions of this relation are specifically unknown, it is to be expected that they should be sometimes absent, sometimes present, in an inexplicable way; and, in particular, that this peculiar function of the brain should be easily disturbed by mental anxiety or discomfort of any kind.15

With regard to the principles on which evidence for psychic phenomena should be assessed, Sidgwick notes that there are immense divergences between different schools of thought and different individuals as to the right manner of dealing with the evidence.

In such inquiries as ours it is inevitable that there should be a very wide margin within which neither side can prove, or ought to try to prove, that the other is wrong; because the important considerations, the pros and cons, that have to be weighed against each other, are not capable of being estimated with any exactness. And therefore there is properly a very wide interval between the point – as regards weight of evidence – at which it is reasonable to embark on an inquiry of this kind and the point at which it is reasonable to come to a positive decision.16

Failure to grasp and come to terms with the existence of this ‘wide interval’ may generate a great deal of tiresome and pointless controversy. According to Sidgwick, the root of the problem is that, in handling apparently well-authenticated testimony for a ‘marvellous fact’, we have to weigh opposing improbabilities against each other. He states, ‘It is improbable that the marvel should have really happened, and it is improbable that the testimony to its happening should be false’.17 All we can do is weigh the improbability of the fact against the improbability that the testimony should be false. And this can only be done not ‘in any scales furnished by exact science, but in the rough scales of common-sense’. Everyone agrees that the greater the marvel, the better must be the testimony, ‘but it is impossible to say precisely what accumulation of testimony is required to balance a given magnitude of marvel’.18

Too many imponderable factors are involved; the probabilities in respect of each of them can only be vaguely estimated; and different people will estimate them differently in accordance with their personal preconceptions and knowledge of the evidence and the witnesses concerned.

What anyone has to do who is convinced himself of the reality of any alleged marvel, is first to try, if he can, to diminish the improbability of the marvel by offering an explanation which harmonises it with other parts of our experience; and secondly, to increase the improbability [of the testimony being in error], by accumulating experiences and varying conditions and witnesses.19

Practical Work

Sidgwick became involved, often alongside his wife, in several lines of practical work, insisting often on the importance of collecting more and still more evidence. Six research committees were set up shortly after the SPR’s foundation to gather materials and conduct experiments, of all of which Sidgwick was a member.  He was especially involved in the collection and assessment of certain cases of apparitions and experiments in ‘thought-transference’ (later called by Myers’s term ‘telepathy’), in which his colleague Edmund Gurney was especially active. A key finding was that apparitions of people believed to be living were often found later to have coincided with the moment of their death, or of their involvement in some life-threatening situation. Sidgwick was already impressed by the experimental and other evidence for telepathy, and  concurred with Gurney’s view that such apparitions were hallucinations telepathically induced in the perceiver by the appearing person at a distance. But he now realized that such cases could not be taken to be evidence for the operation of disembodied mind, and the causal connection should instead be attributed to ‘some occult [hidden] action of the embodied mind, until we have obtained adequate evidence that disembodied minds are possible agents; and we do not yet think that we have obtained such evidence’.20

In short, what had initially seemed one of the most promising lines of work undertaken up to that date by members of the SPR had not merely failed to support, but threatened to end, his hopes that psychical research might yield some intimations of an existence beyond the transient one of which alone we have certain knowledge. This failure contributed towards the deep depression that Sidgwick suffered the following year.

Sidgwick later became  involved in two extensive investigations of telepathy. One of these, a series of experiments carried on by his wife, himself and Alice Johnson between 1889 and 1892, was mainly on the telepathic transfer of two-figure numbers. The results were positive. The results were attacked by critics on the grounds that they might have been facilitated by  ‘involuntary whispering’, to which Sidgwick replied with a detailed analysis of his critics’ logic and statistics, and experiments of his own to test the viability of his opponents’ hypothesis.21

Sidgwick also headed a new project to carry out a census of hallucinations, based on an earlier project by Gurney, to assess the chance-coincidence hypothesis of ‘crisis hallucinations’, a large class that were found to have occurred around the time of the death, illness, injury or other crisis occurring to the person seen in the hallucination). The idea was set forth by Sidgwick in the SPR’s Journal in April 1889, along with an appeal for volunteer collectors. Sidgwick fronted the presentation of interim reports and of a report to the succeeding International Congress, London, 1892 (of which he was president), and shared in the work of interviewing witnesses. The committee’s conclusions stated:

We have shown that – after making the most ample allowance for all ascertainable sources of error – the number of these experiences remains far greater than the hypothesis of chance-coincidence will account for; thus confirming the conclusions already arrived at by Mr. Gurney [including viability of the telepathic theory of crisis hallucinations].22

Leonora Piper

Sidgwick held sittings in 1889-90 with the Boston medium Leonora Piper, during her visit to England to submit to investigation by the Society. Sidgwick was not much involved in this research, and his own experiences were insignificant. But she impressed his colleagues, who were convinced of a paranormal process – of telepathy if not necessarily of spirit agency – and this in turn impressed Sidgwick, who believed they were ‘on the verge of something important’, and continued to take a strong interest in the continuing researches with Piper during the following decade.23  In 1898, he commented on the views of the principal investigator Richard Hodgson, who had abandoned an earlier adherence to the telepathic theory and had become convinced that the communicators who spoke through Piper were not all secondary personalities but discarnate spirits.24

Sidgwick remarked that he was willing to admit that some of the evidence would (if obtained under varied conditions and far enough increased in quantity to be submitted to statistical treatment) ‘certainly point to the adoption of some form of ‘spiritism’ as a working hypothesis’. In the present condition of the evidence, he could not say more than that ‘a primâ facie case had been established for further investigation, keeping this hypothesis in view’. But some of Piper’s ‘control’ personalities were unconvincing, and a later in-depth analysis by his wife Eleanor pointed to their being secondary personalities.

Elsewhere, Sidgwick is reported as saying that in his view ‘it would be necessary, before arriving at a final decision with regard to evidence, to extend the scope of the investigations and obtain phenomena from other persons. He could not share Hodgson’s conclusions on the basis of evidence obtained from one medium alone, but nevertheless thought it was ‘important to make the most we could, by careful and repeated consideration, of the Piper phenomena’. 25

Final Views on Telepathy and Survival

By this time Sidgwick appeared to have shifted slightly towards the survival hypothesis he would like to have believed in, foreseeing that he might one day have to accept it as a ‘working hypothesis’. But for the moment was still sticking to the telepathic theory. At this time, some believed that the mere occurrence of telepathic communication would itself suffice to prove the immateriality of mind,26 but there seems to be no evidence that Sidgwick shared this view. He never offered any proposals as to the nature of telepathy, and it is not easy to work out how he could have fitted it into other aspects of his thinking.

Sidgwick did not need telepathy to disprove hardcore materialism, as the little that he wrote on philosophy of mind indicates. He agrees that ‘we have overwhelming – though to a considerable extent highly inferential – grounds for believing that psychical facts such as sensations, emotions, thoughts, volitions, have always corporeal concomitants in movements of nerve-matter.27 But he adds that ‘the prima facie disparateness of mental facts and nervous changes, the apparently total absence of kinship between them, puts in the way of any materialistic synthesis an obstacle difficult to overleap.28. Even ‘instructed thinkers of a materialistic tendency’ now admit that psychology deals with ‘double facts’, psychical and physical, whose connection no-one professes to understand. The casus belli between materialists and their opponents is over the causal links between successive double facts, with materialists claiming that the causal nexus lies wholly on the physical side. (Some‘instructed thinkers’ today hold analogous views).

It seems likely that Sidgwick’s preference for common-sense ‘natural dualism’ would have led him to leave open the possibility of mental causation between successive ‘double facts’ in the same mind (or series of double facts), or even between the mental aspect of a double fact in one mind and a double fact in another mind, thus leaving him with a way of tackling the phenomenon of telepathy.

It is doubtful that such an approach to the mind-brain problem and to telepathy could have been adequately squared with Sidgwick’s belief that a ‘perduring ego’ is an object of immediate intuition, or with his view that ‘no attempt to analyse [cognition] completely into more elementary psychical facts has succeeded… or is likely to succeed’.29 Yet acceptance of telepathy remained central to his way of thinking about psychical research, and an impediment to his hopes of progressing with the question of life after death.

Alan Gauld


Bucolo, P., Crisp, R. & Schultz, B. (2007). Henry Sidgwick Happiness and Religion. Department of Human Science, University of Catania.

Hodgson, R. (1898). A Further Record of Observations of Certain Phenomena of Trance. Proceedings of the Society for Psychical Research 13, 284-582.

Myers, F. W. H. & Lodge, O. (1901) In Memory of Henry Sidgwick. Proceedings of the Society For Psychical Research 15, 452-64.

Myers, F. W. H. (1903). Human Personality and its Survival of Bodily Death, London: Longmans, Green & Co.

Schultz, B. (2015).  ‘Henry Sidgwick’, in Edward N. Zalta (ed.),  Stanford Encyclopedia of Philosophy (Summer Edition), https://plato.stanford.edu/archives/sum2015/entries/sidgwick/

Sidgwick, A. & Sidgwick, E. (1906). Henry Sidgwick: A Memoir. London and New York, Macmillan.

Sidgwick, H. (1882-1883). Address by the President at the First General Meeting. Proceedings of the Society of Psychical Research 1.

Sidgwick, H. et al. (1887). In Presidential Addresses to the Society for Psychical Research 1882-1911 (1912), 1-2.

Sidgwick, H.  1996-1997. ‘Involuntary Whispering Considered in relation to Experiments in Thought-Transference’. Proceedings of the Society for Psychical Research 12, 298-315.

Sidgwick, H, Sidgwick, E. & Johnson, A. (1894). ‘Report on the Census of Hallucinations’. Proceedings of the Society for Psychical Research 10, 25-422.

Sidgwick, H.  (1902a). Philosophy, Its Scope and Relations: An Introductory Course of Lectures. London: Macmillan,.

Sidgwick, H. (1902b). Lectures on the Ethics of  T. H. Green, H. Spencer and J Martineau, edited by E. E. Constance Jones. London and New York: Macmillan & Co.

Society for Psychical Research (1899).  ‘General Meeting’. Journal of the Society for Psychical Research 9, 162-9.

Strutt, J. W. (Lord Rayleigh) (1920). ‘Presidential Address’, Proceedings of the Society for Psychical Research, 30, 288.


  • 1. Bucolo et al (2007), 160-257.
  • 2. Sidgwick & Sidgwick (1906), 14.
  • 3. Schultz (2015).
  • 4. Sidgwick & Sidgwick (1906), 466.
  • 5. Sidgwick & Sidgwick (1906), 347.
  • 6. Myers (1900-1901), 454.
  • 7. Sidgwick & Sidgwick (1906), 106; see also Myers (1903), 2, 122-123.
  • 8. Sidgwick & Sidgwick (1906), 289-291.
  • 9. Sidgwick et al. (1912), 1-2.
  • 10. Sidgwick et al. (1912), 35-37.
  • 11. July 16th 1887.
  • 12. Sidgwick et al. (1912), 36.
  • 13. Sidgwick et al. (1912), 6.
  • 14. Sidgwick et al. (1912), 40.
  • 15. Sidgwick et al. (1912), 21-22.
  • 16. Sidgwick et al. (1912), 47-48.
  • 17. Sidgwick et al. (1912), 48.
  • 18. Sidgwick et al. (1912), 49.
  • 19. Sidgwick et al. (1912), 50-51.
  • 20. Sidgwick et al. (1912), 37-38.
  • 21. Sidgwick (1996-1997), 298-315.
  • 22. Sidgwick, Sidgwick & Johnson,  (1894), 393.
  • 23. Sidgwick & Sidgwick (1906), 502, 507.
  • 24. Hodgson (1898), 357-412.
  • 25. Society for Psychical Research (1899), 68.
  • 26. See for instance, Strutt (1920), 288.
  • 27. Sidgwick (1902), 52, cf. 144.
  • 28. Sidgwick (1902), 54.
  • 29. Sidgwick (1902a), 86-87; see also Sidgwick (1902b), 3.