Alister Hardy: A Naturalist of the Spiritual Realm

: Alister Hardy was one of the pioneers of the scientiﬁc study of spiritual experiences (SE); however, his work and insights have not received the attention they deserve. This paper, based on an in-depth analysis of Hardy’s own writings, presents his main methodological and epistemological contributions for advancing the investigation of SE. Hardy’s main epistemological propositions were as follows: the transcendent as the core of spirituality and SE as a major source of R/S beliefs; a nondogmatic approach, acknowledging that Darwinian evolution does not imply materialism and that mind is not reducible to matter; and a call for studies of psychic experiences and considering an expanded naturalism, including the “para-physical”, that could lead to a perennial philosophy and a natural theology. His methods focused on phenomenological classiﬁcation and the development of a natural history of SE based on studies with proper ecological validity on the experimental and the experiential, mixing large surveys of the general population with in-depth qualitative studies of the most prominent cases. In addition, it would be worth investigating developments of SE throughout a person’s life. Bringing back Hardy’s contributions will foster a better understanding of the history of the scientiﬁc study of SE and provide key insights for moving it forward.


Introduction
Since the late 19th century, there have been several predictions in the academic world that a strong and inevitable secularization was underway, and that religion and spirituality (R/S) would fade away (Stark 1999). However, recent global surveys contradict these prophecies, and currently, more than 80% of the world's population report having a religious affiliation, with 74% saying that religion plays an important part in their daily lives. Based on recent findings, these figures will likely continue to increase in the coming decades (Pew Research Center 2017;Stark 2015). In the last few decades, there has been a great increase in the number of studies focusing on the relationship between R/S and health (Koenig et al. 2012). However, studies of spiritual experiences (SE) have not received the same attention. This is unfortunate, because SE are widely prevalent across generations and cultures, and are considered to be at the root of the world's major spiritual traditions and religions, forming a key element of most people's R/S (Walach 2014). During the transition from the 19th to the 20th century, SE received much attention from researchers, including in William James' seminal Varieties of Religious Experience (James 2002). However, studies decreased sharply during the 20th century and have resumed only recently (Cardena et al. 2014;Daher et al. 2017; Moreira-Almeida and Santos 2012; Schmidt and Leonardi 2020;Schmidt 2016).
Scientific studies of SE face several epistemological and methodological challenges, as well as prejudices that jeopardize further developments. Perhaps because SE usually suggest, at least prima facie, some transcendent, nonphysical, aspect of reality and of human beings, they have often been neglected in the study of R/S (Cardena et al. 2014). As a consequence, investigations into R/S have most commonly focused on beliefs and practices such as church attendance or rituals. Discussions about the definition of spirituality also reflect frameworks that are stripped from a transcendent core and equated to psychological constructs such as a sense of peace and the meaning of life (Koenig et al. 2012, Moreira-Almeida andBhugra 2021). Finally, when SE are investigated, there is an effort to constrain them with psychophysiological explanations, following the Methodological Exclusion of the Transcendent proposed by Flournoy (1902) more than a century ago (Hood et al. 2018). These are some of the challenges currently faced in the academic study of R/S that may be overcome by more rigorous and open-minded investigations of SE.
The Oxford biologist Alister Hardy was a landmark figure in the field, both in terms of conducting a large national survey of SE in the UK and regarding his bold and thoughtful insights concerning scientific investigation of SE. Based on his vast and universally recognized expertise as a biologist, he pursued and argued for a "natural history" of SE, making him the first scientist to win the Templeton Prize in science and religion (Prize 2020). He saw himself as a naturalist of the spiritual realm (Hardy 1971(Hardy , 1979. Unfortunately, Sir Alister's ingenious thoughts on the epistemology and methodology that may be very helpful in moving the study of SE forward, as well as his scientific exploration and understanding of SE, have not received the attention they deserve. This paper will provide a description of the epistemology and the methodology developed by Alister Hardy in his studies of SE. For the sake of precision and accuracy, this paper will address what Hardy himself wrote on this topic, instead of second-hand descriptions of his approach. The proposal of this paper will be informative regarding Hardy's ideas and will discuss how he was the precursor of other methodological approaches. We will start by presenting a brief biography, emphasizing his life before redirecting his academic career to the scientific exploration of SE in the last two decades of his life. Next, we will discuss his epistemological and methodological insights regarding R/S and science. Finally, we will briefly present ongoing research developments in the Religious Experience Research Centre (RERC), founded by him.

Sir Alister Hardy (1896-1985)
When accepting the Templeton Prize in 1985, Alister Hardy reported that his interest and commitment to spirituality started with SE in childhood: "I came to know what I have always regarded as God when quite a boy; it was not the result of church services, of school chapel or of scripture lessons, but for quite other reasons . . . I came to feel the experience of God through the beauty and joys of nature.
From very early days I was a keen naturalist and, when out on country walks by myself looking for beetles and butterflies, I would sometimes feel a presence which seemed partly outside myself and curiously partly within myself. My God was never 'an old gentleman' out there, but nevertheless was like a person I could talk to and in a loving prayer could thank him for the glories of nature that he let me experience." (Hardy 1997, p. 1) In 1917, at 18 years of age, when he was admitted to Oxford University, he was an "ardent Darwinian . . . just as convinced of the reality of evolution as I was of man's spiritual experience" (Hardy 1997, p. 2). When he had to leave the University to serve in World War I he "made a solemn vow: that if I came through I would devote my life to trying to bring about a reconciliation of these two great truths" (Hardy 1997, p. 2). Fortunately, he survived WWI and returned to Oxford. However, he postponed his vow and instead followed the recommendation of his father-in-law, a Professor of zoology at Leeds, (Hay 1998) "to build up my scientific reputation as a platform from which to speak, before beginning the actual study of such experiences" (Hardy 1997, p. 2).
Indeed, he pursued a successful career as marine biologist, becoming Professor of zoology at Hull in 1928, Regius Professor of natural history at Aberdeen in 1942, and finally the Linacre Professor of zoology at Oxford in 1945, a position he held until his retirement in 1961. For services to science, he was elected to the Royal Society in 1940, and was later knighted for his work as a naturalist. Though he studied and collected accounts of religious experience throughout his academic career as a biologist, it was only after his retirement in 1961 from Oxford, almost 50 years after his vow during WWI, that he dedicated himself fully to the scientific exploration of SE (Hay 1998 (Hardy 1979). He began gathering accounts by placing adverts in national U.K. newspapers asking for responses to what is now known as the Hardy Question: "Have you ever been aware of or influenced by a presence or power, whether you call it God or not, which is different from your everyday self?" His work during the first years of research at the RERU was documented in his books The Biology of God in 1975, and Darwin and the Spirit of Man 1984. In recognition of his formative research at the RERC, Hardy received the prestigious Templeton Prize in 1985, shortly before his death that same year. In his address to the Templeton Committee, Hardy summarized the purpose of his motivation with these words: "science itself, as we know it, cannot deal with the real essence of religion any more than it can touch our appreciation of art, our joy in the beauties of nature or the poetry of human love. We can, however, use the methods of science to make a systematic natural history study of human experience." (Hardy 1997, p. 1).

Hardy's Ideas on Science and Religion
This section will briefly present some of Hardy's key philosophical and epistemological insights on the relationship between R/S and science and the implications fostering theory and empirical research of SE (see Table 1).
-Concept of Spirituality: Hardy put the transcendental at the core of spirituality, and argued that it is the "essential element" of SE. "The main characteristics of man's religious and spiritual experiences are shown in his feelings of transcendental reality . . . a feeling that 'Something Other' the self can be sensed" (Hardy 1979, p. 131). This conception of "something other than the self" became the foundation of the Hardy Question used to gather personal accounts of spiritual or religious experience.
Hardy argued that SE are the major source of R/S beliefs, "the reality of religion rests upon the evidence of experience" (Hardy 1979, p. 6). For example, SE such as out-of-body experiences "often induces in the person concerned . . . a conviction that the material everyday world is not the whole of reality and that there is another part to life in which the essence of religion lies" (Hardy 1979, p. 36). Hardy did not deny the importance of material aspects, but consider them insufficient to explain spiritual beliefs. These would also be influenced from the direct perception of the transcendental reality through SE. - Overall, his ideas are embedded in the Perennial Philosophy: Hardy (1997) emphasizes the "fundamental similarity" (p. 4) in the core teachings of different faiths. The crossfaith study of SE may contribute to overcoming religious intolerance: "by studying the records of religious experience from many kinds of faith we could, I believe, eventually set the world free from these terrible passions of disagreement" (p. 5). -While he never rejected Darwinism, Hardy argued that Darwinian evolution does not imply materialism. Although he declared himself a "convinced Darwinian" (Hardy 1979), he did not agree "with the unwarranted dogma that belief in modern evolutionary theory shows that the whole process is an entirely materialistic one, leaving no room for the possibility of a spiritual side to man. Unfortunately, many biologists do tell this story" (p. 10). Hardy thought that we should reconcile "Darwinian doctrine of natural selection with the spiritual side of man" (p. 10). -This point led to an expanded naturalism: Hardy argued that R/S are part of nature, of the natural world, forwarding an expanded concept of nature that is not restricted to matter and cannot be explained purely in terms of physics and chemistry. He preferred the word "para-physical" to "supernatural" (Hardy 1979) and argued that studies should not be restricted to the "unproven hypothesis or dogma of materialism" (p. 9). For Hardy, the spiritual nature of man is "a reality" and consciousness is "a fundamental attribute of life" (p. 142). -Following up an expanded naturalism, Hardy argued that mind is not reducible to matter: He assumed a dualist perspective of the mind-brain problem and argued that mind cannot be "completely described in physico-chemical statements" (p. 9). Hence, he agreed "with those great neurologists Sir Charles Sherrington, Sir John Eccles, and Lord Brain, that mental events may belong to a different order which somehow, in a way we do not yet understand, is linked with the physical system" (Hardy 1979, p. 8). -He stressed the importance of studying psychic or extrasensory experiences: Hardy saw that such experiences are often entangled with SE and form the basis of R/S beliefs and feelings (Hardy 1979). At the memorandum to create his research group in SE he listed "studies on telepathy and allied phenomena e.g., Oliver Lodge" as an example of studies he planned to conduct (Morgan 2015, p. 7). Such studies are very important because "iron evidence that one mind can communicate with another by other than physical means . . . would lend plausibility to the possibility that the influence which religious people feel when they say they are in touch with . . . some transcendental element" (Hardy 1971, p. 106). His contribution to this field was publicly acknowledged when he was elected President of the Society for Psychical Research (1965Research ( -1969 (SPR The Society for Psychical Research). -Another important key concept of Hardy's ideas was natural theology: in line with the founders of modern science (Kepler, Galileo, Newton, and others) he believed scientific investigation of nature (in the broad sense, including the spiritual realm) would inform us about God and support a "spiritual philosophy" (Hardy 1979).
The scientific investigation of SE may generate, as he wrote, an "experimental faith" (Hardy 1979) based "upon a greatly widened scientific outlook" (Hay 1998, p. 2) which would enable us to overcome materialism and nihilism (Hay 1998;Morgan 2015). -However, Hardy stressed the importance of being free from "dogmas of either materialism or theology" (Hardy 1971, p. 104), believing the naturalist of R/S should always keep an open mind. The study of SE "tend to undermine some cherished modern dogmas", hence he argued, "we must revise the widely accepted outlook held by so many intellectuals of today" (Hardy 1979, p. 142). In his book "The Living Stream", Hardy clearly distinguished the concept of natural theology from the concept of rational theology. Rational theology, he wrote, usually maintains "that God's existence could be proved, as convincingly as a theorem of Euclid, by reason alone," and this was something he could not subscribe to. According to Hardy, the theism related to natural theology is "derived empirically from the study of nature, man and human history" (Hardy 1965, p. 11).
Hardy's epistemological insights may contribute to several of the key challenges faced by contemporary academic studies of R/S. First, regarding the concept of spirituality, Hardy is aligned with many scholars who consider the transcendent as the core essential component of spirituality, although the definition of spirituality has been an ongoing source of disagreement in the last century, especially when the transcendent is signified as a necessary component (Smart 1984;McCutcheon 2012). Hardy and others point out that putting the transcendent at the core of spirituality is both faithful to SE first-hand reports (that often point to a transcendental, nonphysical, aspect of human life or the universe) and distinguishes spirituality from other psychological constructs, such as meaning of life or sense of peace. Several authors have pointed out that excluding the transcendent from the concept of spirituality removes its defining characteristic, rendering it indistinguishable from other constructs related to human experience, such as political commitments that generate meaning of life, or psychological states such as sense of peace and well-being. (Hill and Pargament 2003;Koenig 2008;Hufford 2005; Moreira-Almeida and Bhugra 2021). A second key challenge in R/S studies that benefits from Hardy's approach is the study of the nature of SE. Hardy challenges the "Methodological Exclusion of the Transcendent" (Flournoy 1902) along with its variants that argue for a commitment to physicalism (i.e., everything is physical Stoljar 2021) and restrict explanations of SE to the physiological and psychological (Hood et al. 2018). This methodological restriction has been questioned by many leading scholars in the scientific exploration of SE (Beauregard et al. 2014;Cardena et al. 2014;Cardeña 2014;Hood et al. 2018;James 2002;Kelly et al. 2007Kelly et al. , 2013Kripal 2010;Miller 2012;Moreira-Almeida and Santos 2012;Myers 1903;Walach 2014). In this sense, Hardy aligns himself with a long tradition of scholars who do not conflate naturalism with physicalism and argue that nature may also have consciousness/mind/spirit/soul as one of its irreducible components (Josephson-Storm 2017; Moreira-Almeida and Santos 2012; Nagel 2012). He rejects the alleged need of restricting human nature, especially mind and SE, to the realm of physical and chemical properties. SE may point to a complementary aspect of nature that, although nonphysical, may not be supernatural or amenable to scientific exploration. For example, an out-of-body experience occurring during a neardeath experience in a cardiac arrest does not necessarily need to be fully explained by biological (e.g., hypoxia), psychological (e.g., fear of death and imagination) or social (e.g., shared religious beliefs) influences. These influences may explain much of this SE, but not necessarily all of it. For example, reports of veridical perceptions of events occurring during cardiac arrest might indicate that consciousness can exist beyond the physicochemical processes of the brain ( van Lommel 2011). This expanded naturalism could be a key element in generating a natural history of the spiritual realm through a rigorous and open-minded exploration of a large variety of SE. Such an approach has been significantly influenced by William James (James 2002;Sech Junior et al. 2013), and has also been proposed by current researchers (Beauregard et al. 2014;Hood et al. 2018

Methods for a Natural History of the Spiritual Realm
Hardy's methodology was phenomenological and integrated notions of 'experimental' and 'experiential,' both of which he saw as scientific methods. His understanding in particular of 'experiential' as a scientific method is still challenged by some scholars, who argue that SE are unavailable 'for empirical (sensory) confirmation' (McCutcheon 2012, p. 8). However, Hardy, being a scientist, had a different understanding of 'experiential'. He insisted that, according to the Concise Oxford Dictionary, the term 'experiential' is defined as being "based on experience" and "not on authority and conjecture," which was previously assumed by those conducting scientific "tests, trials or procedures on the chance of its succeeding" (Hardy 1979, p. 139). He introduced the concept of "experimental faith", in approximation of Karl Jasper's concept of "philosophical faith" (Jaspers [1948] 2003). Hardy argued that although there is no scientific evidence for a certainty that is based on faith, there is a kind of truth that, without being irrational, can be supported by experimental faith and the evidence of its results.
Hardy was heavily influenced by William James, whose Varieties (James 2002) he considered the greatest book "on the relation of man to the cosmos since the publication of Darwin's Origin of Species" (Hardy 1997, p. 2). In combination with his broad understanding of an enlarged nature (that includes spiritual, nonmaterial aspects) he devised and applied several practical methodological approaches in the empirical study of SE.
His "naturalist's approach" is based on his biological outlook. Hardy pursued "a true natural history of this [religious] side of man" (Hardy 1997, p. 5). One of his main targets was therefore the collection of a large number of experiences that also cover a wide range of different types of SE in order to "build up a body of knowledge of actual experiences . . . first-hand accounts . . . , looking at their development, . . . antecedents and consequences . . . to draw certain tentative conclusions" (Hardy 1979, p. 2). As a scientist, he aimed to compile a large amount of data in order to look at SE from a quantitative approach.
Another core aspect of his method was to study SE in modern societies rather than primarily in "exotic" cultures. Hardy appreciated anthropology and its study of SE during the 20th century while much of the scientific community neglected and ignored such study. However, while he noted that only the anthropologists studied SE, they did so mainly outside their own countries. He was concerned that "we know much more about the religious feelings of Polynesians, North American Indians, and various tribes in Africa than we do about those of our fellow-citizens in Western society" (Hardy 1979, p. 6).
In order to understand SE in our own societies, he issued calls to the general population to report SE, broadening out the study of SE rather than limiting it to exceptional people. He put adverts in newspapers, made appeals during interviews, and published pamphlets in order to reach a wider public and thus collect a wider array of SE (Hardy 1979). While the response to his initial adverts in church magazines was limited, he received a growing number of letters after placing his adverts in national newspapers such as The Guardian, the Daily Mail, the Observer and the Times. In line with contemporary ethical standards of research practice, Hardy assured the confidentiality of every participant. Given the personal significance and highly sensitive nature of SE, it was essential to Hardy to ensure "the confidential treatment of the material" in order to insure open and sincere reports (Hardy 1979, p. 21).
The amount of data he collected enabled the application of quantitative methods. He argued that the use of representative samples of the general population was crucial in order to reveal the prevalence of SE, their predisposing factors, sociodemographic distribution, common features, and correlates with mental health and well-being. (Hardy 1979).
In addition, Hardy acknowledged the importance of in-depth qualitative studies. He insisted on the importance of collecting detailed first-hand accounts of SE that "must be the more profound aspect of our work" (Hardy 1979, p. 16). This approach draws its inspiration from biology where "a truly quantitative science of living things was however made possible only by the foundations laid down by the observations of the field naturalists first explored the natural world" (Hardy 1979). In addition, he argued for the importance of "spontaneous cases of psi phenomena . . . to be found in the volumes of the Societies for Psychical Research . . . We must not forget that discoveries by observation may be just as important as those demonstrated by experiment" (Hardy 1971, pp. 105-6).
For Hardy, in-depth investigation of the most prominent cases of SE is needed for a better understanding of SE. He argues for the need of "personal interviews with the more interesting cases" (Hardy 1997, p. 5). With in-depth interviews it is possible to study individual developments of SE throughout a person's life. Hardy saw SE not as static or standardized and argued instead that each person has a unique dynamic in his/her SE: "the more I study the significant features in the development of man's spiritual life, the more apparent it becomes that there are no 'normal' patterns: each individual must find his own and it is the discovery of such personal pattern that appears to be an essential part of all experience truly called religious" (Hardy 1979, p. 68).
Based on his data, Hardy developed a classification based on the characteristics of SE. Initially he tried "major subdivisions" in a "hierarchical system like biological specimens" (Hardy 1979, p. 23); however, this approach did not work because of the prominence of mixed characteristics, as well as many combinations of SE features. He therefore adopted a provisional classification system in which each SE received "classificatory labels" (p. 24) describing the several phenomenological characteristics of a given SE (e.g., feeling of unity with the surroundings + sense of joy + sense of awe).
Ecological validity was also important for Hardy. He encouraged avoiding artificial research procedures, which could jeopardize the study of SE, writing: "the specimens we are hunting are shy and delicate one which we want to secure in as natural a condition as possible; we must at all costs avoid damaging or distorting them by trying to trap them within an artificial framework" (Hardy 1979, p. 21). One example was his criticism of Rhine's telepathy experiments with card-guessing tests and he advocated for more naturalistic studies on telepathy (Hardy 1971).
These methodological guidelines are relevant in filling important gaps in the current scholarship on R/S, which includes the shortage of studies of SE. Of importance especially are the experiences noted by William James, as "those obscure and exceptional phenomena reported at all times throughout human history [ . . . ] religious conversions, providential leadings in answer to prayer, instantaneous healings, premonitions, apparitions at time of death, clairvoyant visions or impressions, and the whole range of mediumistic capacities" (James [1898(James [ ] 1960. Too often, these experiences have been neglected in research and theory in R/S, which has emphasized more conventional beliefs and religious behavior (Cardena et al. 2014;Stark 2017). It is worth noting that exceptional SE were a formative influence in the origins of the scientific study of religion (Tylor 1871;James 2002; Lang 1898) but largely forgotten for the past one hundred years and only recovered in recent decades (Cardena et al. 2014;Daher et al. 2017). In addition, even when those SE are studied, they are often investigated in small samples or individual cases in non-Western cultures. There is a great shortage of large population studies that focus on the prevalence and features of SE. One of the first and few studies of this sort was the "Census of hallucination", developed by the Society for Psychical Research, that involved more than 2000 respondents from the UK general population in 1894 (Sidgwick et al. 1894). Eighty years later, Hardy resumed this type of research with his national survey of SE in the UK. Following in this tradition, it would be valuable to have transcultural (ideally longitudinal) studies of large community samples that reveal the prevalence, phenomenology, precipitants and impacts of SE. The study of transcultural variants and invariants of SE would then contribute to theoretical developments. In addition, the most prominent cases of SE could be submitted to in-depth investigations, including, in addition to qualitative interviews, a wide range of evaluations such as psychological, neuroimaging, physiological and genetic.
In summary, the most relevant aspects of Hardy's methodology include the in-depth investigation of all sorts of SE, while respecting their nature and requirements (see Table 1). The emphasis on detailed qualitative investigation of spontaneous psychic and/or spiritual experiences in addition to quantitative and experimental studies would give rise to a better understanding of SE, especially in the current initial (natural history) phase of scientific exploration. This mix of approaches respecting ecological validity has recently been proposed as strategies to move forward the theory and research on SE (Belzen and Hood 2006;Cardena et al. 2014;Moreira-Almeida and Lotufo-Neto 2017).

The Posterior Developments of Research in the RERC and Its Connections and Differences from the Hardy's Original Methodology
As pointed out by the social psychologist Argyle (1997), who worked very closely with and was linked to the RERC for many years, in not adopting a given a priori ontology for SE, Hardy created a methodology "to study religious experiences and beliefs as empirical phenomena regardless of whether they are true or valid" (Argyle 1997, p. 1). Although Hardy (following James) believed that SE have an ultimate transcendental ontology-"a spiritual dimension outside that of the strictly physical" (Hardy 1979, p. 44) and may have ethical and philosophical implications, he adopted methodological strategies that made it possible to perform studies in different religious or nonreligious contexts, across cultures, without taking a priori positions regarding ontological truth or validity. In a phenomenological approach, Husserl named this attitude époché, meaning avoiding a dogmatic attitude as a researcher, and avoiding reductionism. This attitude and practice has directly inspired many researchers to adopt similar approaches. The following are some examples of Hardy's legacy and the scholarship he has inspired. Robinson (1977bRobinson ( , 1978 was a biologist like Hardy and became the director of the RERC after Hardy stepped away from it. Robinson worked on the improvement and extension of the taxonomy as a base of scientific collecting, observation and classification of SE. Of special interest for Robinson (1977a) were SE during childhood. He considered childhood as a unique dimension of life rather than merely a chronological period. His work was continued by the biologist David Hay and psychologist Rebecca Nye Nye [1998] 2006), who investigated the dimensions of SE with primary school-age children in UK. Nye further included not only the analyses of children's verbal expressions but above all their symbolic language, their own perceptions of faith and visions of God in their own terms (Nye 2009). Hay (1982), who became director of the RERC, as well as subsequent directors contributed to the expanded collection of SE accounts by adding representative experiences from a variety of cultures such as China, Turkey, Japan, India, Russia, Brazil, USA and Taiwan (e.g., Dickie 2007;Franklin 2014;Greeley 1975;Tsai 2013;Yao and Badham 2007;Yaran 2015).
Examples of methodologies recently developed in RERC's research include contextual narrative studies (Dossett 2019;Schmidt 2020), humanistic and phenomenological contributions (Freitas 2020), and ethnographic and ethnohistoric approaches (Pierini 2016(Pierini , 2020Schmidt 2014aSchmidt , 2014bSchmidt , 2016Schmidt , 2017. We see in these recent methodological alternatives adopted by RERC researchers another side of Hardy's legacy-an interdisciplinary and multidisciplinary focus on SE research. This was anticipated by Hardy in his opened-minded approach that looked beyond biology and theology, and included a unique openness to anthropology (Hardy 1979).

Conclusions
Throughout this article, we have sought to summarize Alister Hardy's main epistemological, conceptual and methodological contributions to the study of SE, what he called the "Spiritual Nature of Man." In terms of epistemological contributions, he offered an alternative that brings together different fields of knowledge-in particular biology and theology-to better understand SE, without creating a division between knowledge and experience. In his conceptualization of SE, he maintained a connection between the immanent and the transcendent, as well as a link between empirical data and philosophical conceptions. In terms of methodology, he showed the rich possibility of combining scientific rigor with genuine respect for human experience, without incurring any reductionism of SE to satisfy a specific theory or to align with an artificial method. This paper does not argue that Hardy's insights and guidelines are flawless or that they should be uncritically accepted and implemented. However, we do argue that the academic study of SE would benefit from serious consideration and discussion of Hardy's ideas in a multidisciplinary context. The utilization and adaptation of a number of Hardy's ideas could significantly advance our understanding of SE.
Indeed, we can use the same expression put forward by Morgan (2015), i.e., "continuing the heritage", to refer to the growing body of work initiated by Hardy, which can be identified in much subsequent research on SE conducted in different disciplines (biology, anthropology, psychology, psychiatry, sociology, philosophy, linguistics, and so on), directly linked to the RERC or beyond it. As often happens with great pioneers, their subsequent heritage is more than a mere continuity. Instead, pioneers inspire diverse avenues of continuing research.
However, what is truly concerning in the contemporary study of SE is how the contributions of early pioneers like William James and Alister Hardy have been forgotten or neglected, resulting in what Carrette (2002) calls disciplinary amnesia. This type of amnesia, often the result of differing ideologies, has the unfortunate consequence of obscuring the pioneers' impact on developments in the discipline, as well as neglecting their great utility for furthering our knowledge about SE.