Introduction

A disease can pose a remarkable threat to us, as seen with COVID-19. On the other hand, we can experience it without any noticeable threat, as with a mild headache or a cold. Whichever the case may be, a disease is “something with vicious effects,” or a contamination to avoid. As we try to avoid it, however, we inevitably must face illness. According to Susan Sontag, the disease is “the night-side of life” and a “more onerous citizenship” (Sontag, 1977, p. 3).

What is a disease?Footnote 1 Bjørn Hofmann notes that the conceptual definition of “disease” varies and that the terms used for this definition are not uniform. He argues that disease cannot be defined by a simple word and is rather “a complex concept” (Hofmann, 2001, p. 217). Just like the scope and complexity of the concept, a disease is understood in diversified contexts. With this notion that disease is understood in various ways without any explicit or unified definition, Germund Hesslow emphasizes that too many concepts of disease “do not play any significant role in medical judgment.” Moreover, he sees it as nothing more than an obstructive, nonsensical “illusory” concept (Hesslow, 1993, p. 3). According to him, philosophical analyses of disease do little to help further scientific understanding or medical practice. He claims that we need to find a method that is useful for medicine.

While concurring with Hesslow’s argument that research contributing to the field of medicine is necessary, this paper maintains that a phenomenological understanding of disease is helpful for medical practice. As Hofmann explains, conceptual definitions of disease vary, and these may be deemed futile if they offer no concrete help for clinical treatment. This issue could be resolved if we can secure a practical understanding of disease concepts that can genuinely contribute to medicine. No matter how diverse the concepts of the disease may be, we aspire to comprehend the nature of the disease. we all experience disease at some point in our lives, so disease is an object we want or need to identify. Most of the elderly in the world suffer from an “ill-defined disease,” and specifically that disease is a leading cause of death for people aged over 75 years of age worldwide.Footnote 2 In this point, we can say that diseases are closely related to understanding human life. Hesslow compares the futility of the philosophical concept of disease to the case of “car maintenance” (Hesslow, 1993, pp. 1–2). Just as a car can be repaired when it breaks down, disease is the same as being repaired by a car mechanic. What we cannot disregard here, however, is that disease experiences are with human beings, not cars.

As James A. Marcum points out, modern medical science is overly dependent on mechanical reductionism, which leads to problems when “humane” diseases are viewed as mere mechanical dysfunctions (Marcum, 2008, p. 10). Marcum points out that such a tendency is due to disregarding the holistic meaning of diseases that can be discovered on the qualitative dimension. Edmund Pellegrino, a renowned American philosopher of medicine, argues “Medicine is the most humane science, the most empiric of arts, and the most scientific humanities” (Pellegrino, 1979, p. 17). According to Pellegrino, medical science, which necessarily presupposes the liberal arts, is a scientific “liberal art.” If life from birth to death is interwoven with the disease, medical science, which seeks the understanding of humans, is necessarily accompanied by the understanding of the disease. Understanding the suffering of a disease is, above all, about considering how to live better, and in this sense, a philosophical analysis of the disease is necessary.

Considering the essential nature of a philosophical understanding of disease, this paper aims to highlight the utility of Husserl’s transcendental phenomenology. Grounded in the recognition that a philosophical perspective is crucial for comprehending illnesses, this study will assert the advantageous nature of employing Husserl’s philosophical framework for a more insightful exploration of disease. Even Jonathan Sholl, who saw a naturalistic understanding as enabling a dynamic examination of illness from various aspects, acknowledges the significance of the phenomenological perspective. According to him, a phenomenological perspective offers a method to explore the foundational structure of the experience of illness through the richness of experience and transcendental methods (Sholl, 2015, pp. 395–400). This article will present the practical value and potential by demonstrating that his transcendental phenomenological methods of inquiry have useful significance for understanding disease. To achieve this, I will briefly examine the misunderstandings about the disease in the section “Some misunderstandings about diseases” and address why phenomenology is helpful in understanding disease, followed by a concrete exploration of the characteristics and utility of phenomenological methods in the section “Phenomenological understanding”.

Some misunderstandings about diseases

In general, people believe the disease is a type of internal state that brings an impairment of average functional ability. Christopher Boorse defines disease as a “function” that refers to making “contributions” to organisms achieving biological “goals” (Boorse, 1975, p. 57). Take typing on a keyboard as an example. If the goal is to type on the keyboard with your fingers, people with normal fingers will have no problem. In other words, the fingers that achieve the goal of typing on the keyboard are in a state of normal function, while the fingers would be in a state of disease if this task is impossible. To move the blood through the body by regular contractions, our heart is in a state of normal function when it has no problems to circulating the blood. The heart, exercising normal function, is in a state of zero diseases, namely, a healthy state. If seeing well is the goal of the eyes, the state of eyes that cannot see puts them in a state of disease. These explain why “health is the absence of disease” (Boorse, 1997, p. 8). In other words, it means “disease is not being healthy or being deviated from normal functions.”

From this point of view, disease is a condition that deviates from normal functions or cannot perform normal functions. Boorse described disease characteristics with the analogy of a “Volkswagen” (Boorse, 1975, p. 59). If the Volkswagen is broken and does not function, the problem is addressed by finding an auto mechanic to fix the broken car. Just as a car mechanic fixes a problem in the vehicle, any person with a disease can go to a professional doctor to cure the disease. Physicians have the task of returning the state of disease, in which normal functions cannot be exercised, to the state of normal functions since normal functions for the survival and reproduction of a species are “both necessary and sufficient for defining disease” (Sisti and Caplan, 2016, p. 7).

If we comprehend disease as a malfunction, however, we may overlook the positive aspects and diverse experiences that disease entails. The definition of disease varies according to time and culture. Sometimes we witness experiences of illness, such as severe headaches, fevers, or chills, which may give the person “religious visions” or “spiritual insights” (Carel, 2016, p. 66) that serve as a source of regained vitality. These experiences also provide an opportunity to see life differently. Havi Carel suggests that the coronavirus disease also allows us to perceive our lives in an entirely different way. Such instances indicate that what is considered an illness is helpful to living. Abnormality is not always understood as a negative concept.

With this understanding as a base, we can raise the second issue: disease can be related to subjective valuation. The disease is attached to valuation in that the state of the disease is accompanied by suffering. The disease is a state of “dis-ease.” Generally speaking, a disease accompanying “suffering” damages the state of “well-being.” In other words, disease reflects human expectations to avoid these damages. The state of “well-being” or the state of “no disease” differs in different people, which leads to the fact that the state of “well-being” or the state of “good health” is inevitably under evaluation. According to William E. Stempsey, “pathology is not divorced from clinical medicine and is not value free,” even in speaking about the “nerve” or “organ” from a pathological perspective (Stempsey, 2000, pp. 326–327). It is because the experience of a disease must include the total circumstances. Take headaches as an example: the experience of headaches cannot be simply explained as an abnormal state. We do not understand a headache simply as a malfunction of specific nerve cells in the brain. The illness we call a headache is experienced through many phenomena, such as declining concentration, stress, problems in completing various daily tasks, etc. The disease cannot simply be understood as a matter of “with disease” or “without disease” by mere natural facts that are calculated or measured. Since the disease can be understood as a “continuum” (Kaplan, 2009, p. 44) that cannot be calculated but can persist somewhere. It shows that our understanding of the disease should not be judged only as describable in quantitative terms but as something that encompasses various contexts.

Once again, it is emphasized that the reason to explore various contexts in understanding diseases is that normal standard values may be understood differently depending on age, region, and race. Therefore, the disease may be experienced in different ways and with varying levels of distress. If standard statistics turn out differently in different circumstances, it is indisputable that being ‘normal’ must be a definition to be understood in relation to the various contexts.Footnote 3 In this point, H. Tristram Engelhardt sees that disease is inevitably correlated with values. According to him, the definition of disease “must involve” human valuation regarding certain functions (Engelhardt, 1976, p. 266). The disease is reflective of human expectations to be freed from suffering. From his perspective, health is essentially the state we all desire, while disease is the state we wish to avoid. Health and disease reflect human values for “good” or “not good” Therefore, disease must entail practical treatment in a particular setting or context.

Since essentially related to an individual’s practical motives to cure suffering or discomfort, disease may be understood differently depending on biological, genetic, and sociological perspectives, resulting in different diagnoses. For example, COVID-19 may be harmless to asymptomatic people, but for others, it may be a life threat. For each of them, there are different diagnoses for their treatment. The diagnosis of a disease may vary depending on the individual or social conditions. Joseph Margolis argues that “the actual concept of disease cannot but reflect the social expectations” (Margolis, 1976, p. 252). The standard definition of disease varies according to the standard for “normal,” as required by different historical periods or circumstances.

The disease is “not isolated” to the environment surrounding human beings (Nordenfelt, 1995, p. 5). The disease can be defined in “different ways” (Nordenfelt, 1995, p. 9) depending on physical, mental, social, cultural, historical, and religious perspectives. In recognizing that diseases can be understood diversely within different contexts, there is a potential for the misunderstanding that diseases can be relatively understood. As S. Kay Toombs explains by quoting Tolstoy’s novel, The Death of Ivan Ilyich (Toombs, 1987, p. 226), the experience of disease is significant only to the person who has it and presents no significance to others who do not share this experience. In other words, emphasizing only the experience of disease limits the general definition of disease that all can share. Howard Brody argues that the experience of illness can never be standardized, arguing that if diagnosing 12 patients, “we can see a dozen different ways of responding to the illness” (Brody, 1985, p. 252).

Suppose this leads to a situation where treatments for diseases can be as varied as views on diseases themselves. In that case, this can be a problem that causes distrust in the achievements of modern medical science. If practical treatment can be relatively implemented with an understanding of practical motives depending on the context or the subjective experience, this may mean that unified treatment never materializes. With its excessive focus on the social assessment of suffering patients, subjective understanding is limited in setting practical clinical standards for general sharing. While it has positive aspects in understanding the diversity of illness experiences and the broadening of views about illness, the subjective point of view is problematic in that it does not provide a general direction for practical movement. To address such problems, this discussion explores methods of transcendental phenomenology. This paper argues that phenomenology, while affirming the importance of the experience of illness, also presents the possibility of shared elements within our experiences. According to Carel, phenomenology is a “toolkit” enabling patients to describe their experience systematically and comprehensively (Carel, 2011, p. 42). As Tania L. Gergel articulated, phenomenology is “more productive” and aids in elucidating the complexity of understanding illness (Gergel, 2012, p. 1108). In the following section, let us delve further into the utility of phenomenological understanding of illness, particularly in the context of mental disorders. The paper will then explore what it means to understand illness through Husserl’s phenomenological approach.

Phenomenological understanding

Utility of Phenomenological Understanding

As much as it values the importance of experience, phenomenological understanding of illness becomes particularly attentive to patient-centered care by focusing on the patient’s experience. Focusing on the patient’s experience helps facilitate an exploration of what the patient truly desires. According to Carel, a phenomenological understanding of disease prompts medical staff to interact with patients more ethically (Carel, 2011, p. 44). Based on Drew Leder’s argument, a phenomenological understanding of diseases allows for the exploration of various methods to approach treatment more strategically for the impaired body (Leder, 2022, pp. 137–154). This situation is notably evident, especially in comprehending mental illnesses. Because understanding mental illness solely as a neurobiological issue or attributing it to genetic defects in brain function can easily overlook the diversity inherent in a patient’s experience. No matter how closely one examines brain cells under a microscope, one cannot see the patient’s consciousness and experience. As patients exist within the interactive context of their surrounding environment, the examination of a patient’s mental illness should scrutinize the patient’s existential life. Phenomenological methods elicit the fundamental causes of a disease by examining the patient’s lived experiences.

According to Dan Zahavi and Sophie Loidolt, a phenomenological understanding of mental illness has proven its utility through three generations of research. The first generation of phenomenological psychiatric studies, centered around Karl Jaspers, Eugené Minkowski, Ludwig Binswanger, and Medard Boss, exposed shortcomings in the biological understanding of mental disorders. Second-generation research, led by Ronald D. Laing, Erving Goffman, and Franco Basaglia, revealed the association of mental illness with social institutions. Finally, third-generation research, with Frantz Fanon at its core, demonstrated the connection between mental illness and nationalist and colonial domination (Zahavi and Loidolt, 2022, pp. 57–71). By uncovering the fundamental causes of problems through lived experiences, phenomenological methods have positively contributed to expanding the horizons of understanding mental illness. It has allowed for shared insights to be accessible to us all. Phenomenological methods facilitate examining the diversity inherent in the understanding of diseases, which can be subject to bias. Simultaneously, within this diversity, these methods reveal the essence of the disease experience. For instance, one phenomenological method, suspension of judgment (bracketing), aids in advancing a new understanding of the phenomenon of illness by “resisting reductive dominant perspectives” while embracing the diversity of experiences (Carel, 2021, pp. 207–208). Such characteristics suggest the direction clinical practices should aspire to.Footnote 4 At this juncture, we cannot help but to elucidate what phenomenological methods entail. Let us explore this in the following section.

Phenomenological explorative methods

In medicine of phenomenology, understanding illness not only draws on the phenomenology of Husserl but also leads them to utilize and explore Martin Heidegger, Maurice Merleau-Ponty, and Jean P. Sartre in commutative approaches. Compared to their efforts, this paper relies on the phenomenological method of Edmund Husserl, the founder of phenomenology, to understand disease. Husserl did not directly discuss the phenomenological exploration of disease. Nevertheless, we can apply his phenomenological methods to the identification of disease. It is because Husserl’s phenomenological research methods essentially explain not only the essential structure of intentional experience but also the meaning of intentional experience in given objects in various ways. As is well known, Husserl’s phenomenology aims to come back “to the things themselves.” Returning to the things themselves is not different from saying that it begins with our lived experiences. According to him, lived experience is intentional experience. In intentional experience, we identify the object in intentional acts. Husserl calls intentional acts “objectifying acts.” He argues intentionality, as a “being of” or “about something,” is an objectifying act of consciousness that intuitively reveals the essential objects in the perception (Husserl, 2001, p. 314). He believes that the essential understanding of the object is possible through this intentional act (Moustakas, 1994, p. 33). According to Van Manen, this phenomenological method is “to grasp the very nature of the thing” (Van Manen, 1990, p. 177). In other words, Husserl’s phenomenology aims to grasp the essence of lived experience.

Husserl’s investigation, which emphasizes intentional experiences, uses two primary methods: static and genetic.Footnote 5 Genetic analysis is a method that privileges observation from the point of view of continuous becoming. At the same time, the static one observes reality as it is given to the observer at a specific moment (Drummond, 2008, p. 161). Genetic analysis focuses on the phenomena in the process of continuous becoming, and the static method focuses on the essential features of the given phenomena, namely the static method focuses on the eidos of the lived experience and the genetic on its actual manifestations in life. In Husserl’s method of inquiry, both methods should be emphasized, not just one. In the phenomenological method, both static and genetic, Husserl tries to grasp the meaningful essence of living phenomena.

Husserl’s phenomenological study of disease accepts both static and genetic views. He uses this method to broaden the horizon of understanding. While accepting a scientific understanding of illness based on experience and observation, the phenomenological research method takes note of the various qualitative meanings explored through the lived experience of illness. It goes even further and attempts to explain the nature of the meaning of illness as it emerges from the lived experience. In this aspect, research in phenomenological qualitative experiences of disease views to the point of transcendental phenomenology. In contrast to the contradictory stance of objectivity-versus-subjectivity, phenomenology accepts both and defines the essential features of experience with a transcendental method (I will discuss this in detail later).

An important point that should not be misunderstood here is that Husserl’s phenomenological method does not deny the scientific objective method of understanding disease. He emphasizes that “the inductive constituted nature (Die induktiv konstituierte Natur)”Footnote 6 is a world of acts, which is a world identifiable by “causality (Kausalität)” (Husserl, 2013, p. 360), saying that an objective explorative method is an attitude and a way of understanding the world. Natural science is a method of understanding nature. We can observe the world of nature as an objective fact: “As a phenomenologist, I can, of course, at any time, go back into the natural attitude” (Husserl, 1970, p. 210). He says that we could look at an object from the point of view of a father, but also from the point of view of a European or a scholar. Husserl acknowledged the undeniable utility of science and held a favorable view toward it. However, he harbored doubts about the assertion that the scientific method alone is the ultimate and sole means of understanding phenomena. Husserl believed that an attitude toward the contemplation of an object could be freely changed. The same phenomenon can be researched in diverse ways, depending on the attitude. To Husserl, “attitude” is a core concept of revealing phenomenological research methods, referring to the “mode” of treating an object and the world. The same is valid for understanding disease.Footnote 7 A person can adopt a natural attitude toward the study of disease, but a phenomenological understanding of disease can be pursued only by moving from an objective attitude to a phenomenological attitude.

To say that explorative methods can vary depending on the attitude of the viewer means that we can consider “other possibilities thinkable (andere Möglichkeiten denkbar)” (Husserl, 2013, p. 363), apart from a mere objective method. In Husserl’s view, the attitude to understand a phenomenon solely by objective quantitative methods is not seeing the “things-themselves”. It is because the objective explorative method is the attitude to generalize complicated things simply. Husserl defines this “naive” way of understanding as “the naturalizing of ideas” (Husserl, 1965, p. 80) or “in the natural attitude” (Husserl, 1983, p. 54). To Husserl, explorative scientific methods are an attitude to take a simple look at what is being explored rather than to reveal the “things themselves”. The method of emphasizing objectivity, which excludes intentional experience, is a narrow understanding.

The experience of illness has diverse non-quantifiable elements. It needs to be viewed from different contexts, such as the patient’s suffering, stress, family, or social relationships, etc. This also becomes clear in the diagnosis of mental illness. For example, ADHD is not only defined by damage to specific nerve cells in the brain. An ADHD diagnosis can be confirmed from a variety of contexts, and treatments are offered from a holistic perspective. Another example to consider is depression. The causes of depression can be understood in various ways. For instance, factors such as chemical changes in the brain, neurological endocrine abnormalities, neuroimmune causes, genetic factors, individual temperament, psychosocial factors, current lifestyle habits, and health status can contribute. Due to the complexity of psychological and social factors intricately intertwined with these conditions, treating depression is challenging with no unanimous consensus on a singular etiology. We don’t understand ourselves in terms of some technically explained cases, such as our height, weight, heart rate, blood type, or physique. Under these premises, the phenomenological inquiry goes beyond the quantitative natural attitude to demand identification from a fundamental dimension. As is well known, phenomenology tries to reveal the “things themselves” without prejudice. Therefore, phenomenological inquiry goes beyond the natural way of understanding and strives to examine the state of the disease itself in its adequacy.

Phenomenological inquiry requires the inquiring person to change his attitude to stop judgment. Husserl requires a mere objective attitude, once regarded as self-obvious, must be changed to another attitude by “epoché (έποχή)” (Husserl, 1999b, p. 23). Attitude transformation by stopping judgment does not mean denying the natural attitude itself; it means putting parentheses around faith and conviction in a natural attitude rather than unconditional acceptance to explain an experienced state adequately.

As we have seen above, we discovered other facts regarding diseases when we moved away from a mere natural understanding. By suspending judgment through uncritical and simplistic comprehension without considering diversity, we can contemplate new dimensions of experience. By attempting to reveal the various aspects of phenomena vividly, phenomenological exploratory methods reveal aspects of the phenomena that go even further than the limited methods of understanding achieved with a natural attitude. Phenomenological understanding further reveals other aspects of experienced states, explains the meaning of these aspects, and captures the essence of the states. In the goal of exploring the essence, with both static and genetic analysis, phenomenology uses different methods of exploration than subjective perspective, which only emphasizes subjective experiences. Phenomenological exploration is an encouraging exploratory method because it overcomes the problems of relativity of understanding disease.

Changing the attitude from a natural attitude, “phenomenology takes as its starting point the examination of phenomena as they appear in a subject’s experience” (Waksler, 2001, p. 68). Lived experience constitutes the basis of phenomenological analysis, and the “experience” of the person is the fundamental starting point to understanding the “significance and validity” of the phenomena surrounding the person. This is direct because “experience is the primal instituting of the being-for-us of objects as having their objective sense” (Husserl, 1969, p. 164). To understand the nature of experienced states, phenomenology explores the object’s meaning given to the person’s consciousness. We must be careful here to avoid misunderstanding. The exploration of the object in the person’s consciousness does not mean that the phenomenological exploration here is that of subjective psychologism.

Husserl’s phenomenology was born by presenting methods to overcome empirical naturalism (objectivism) and psychologism (subjectivism). Phenomenological exploration does not follow the dualistic classification of objectivism and subjectivism. As discussed earlier, phenomenological exploration regards “intentionality” as a fundamental universal feature of consciousness and takes as its “axiom” the subjectivity of consciousness as fundamentally connected with the object. In phenomenological exploration, the consciousness of the object through intentionality is called the “intentional act,” and phenomenological exploration is primarily performed through “intentional acts.” The object is not considered independent of the explorer. Intentionality essentially constitutes phenomenological exploration, and therefore objectivity always exists in relation to subjectivity. In this sense, Husserl tries to overcome the dualistic method of inquiry (objectivism and subjectivism) in understanding the object.

Exploring the experiences following intentional acts, phenomenology notes qualityFootnote 8 revealed through subjective experiences that are not merely converted into quantity. In phenomenological qualitative research, quality refers to the meaning that constitutes the experiential state that is not converted into quantity. Our experienced states can be analyzed by quantitative methods, as in mathematical economics, insurance design, or experimental psychology. In contrast, phenomenological qualitative inquiry investigates various qualitative meanings that quantitative investigations cannot satisfy.

A person’s experiences can have different qualities depending on the attitude he or she takes toward the object. The qualitative experiences can vary. This is also true for the experience of the disease. As far as disease is concerned, phenomenological qualitative research is interested in identifying the different qualitative meanings of disease. As in the case mentioned above, a COVID-19 infection may cause no problems for some, while for others it may be a life-threatening experience. The disease is experienced differently by different people and reveals an individual qualitative meaning in the body with different “habituality.” When we suffer from a headache, we do not feel a lesion in the nervous system located in specific areas of the brain.

On the other hand, we have direct experience of this damage in everyday life. As we differ in the habituality of the body, the experience of a headache can be felt in diverse ways. The disease causes suffering to the patient, whereas a patient’s disease is experienced by a doctor as “a typical example” to identify within a clinical category (Toombs, 1987, p. 223). The same disease is differently experienced depending on the attitude with which it is viewed.

A lived body (Leib), as the center of intentional acts, can experience disease differently according to physical conditions. Take a patient with “multiple sclerosis” as an example.Footnote 9 They have a myelin sheath, which typically transports nerves from the central nervous system but is damaged, making it impossible to move their legs. For this person with disabilities, who relies on a wheelchair to get around, the disease is not nearly as noticeable as nerve damage. Taking a flight of stairs to the second floor is perceived as suffering by the person with disabilities. For most people, climbing stairs is not a chore, or walking between floors may even be a desirable light activity. For people with disabilities, however, the second floor is experienced as a place that is impossible to reach, a place that is too far away to reach, or a place of suffering. The same place can be experienced differently from the object intended with different physical conditions. An experience of disease changes a person’s “totality” and perspective towards the disease. In the sense of identifying the qualitative significance of diverse experiences, Toombs argues that this phenomenological exploration presents an “enormous practical significance” for “effective therapies” (Toombs, 2001, p. 248). Qualitative significance identified through lived experiences can be revealed differently depending on one’s generation, region, culture, race, and gender, as well as physical conditions. Phenomenology-as-quality research explores the qualitative meaning of these diverse experiences.

If our discussion ends on the dimension that qualitative meaning must be studied as it is revealed through various experiences, then phenomenology as qualitative research is not so different from subjective research of experiences. Phenomenological research methods adopt the list of facts of experiences. However, phenomenological research as qualitative research does not refer only to descriptive phenomenological experiences but focuses on the essential content of experiences. Phenomenological research goes further to try to explain the essence of the object for exploration by use of both static and genetic analysis. Not only that, but phenomenological exploration also takes a deeper dive into the object with transcendental constitutions. According to Husserl, a transcendental constitution means “thinking more (mehr meinen).” With this transcendental constitution, phenomenology seeks the eidetic meaning that makes experience possible. Phenomenological methods are not limited to describing how experiences differ and what is in each of their experiences. For example, according to Toombs, the experience of illness of a person with disabilities vis-à-vis a space in eidetic meaning is defined as “existential fatigue” (Toombs, 2001, p. 253). The source of these experiences is essentially in “suffering,” and “existential fatigue” is the fundamental eidos that constitute the experiences of people with disabilities. Because for individuals with a disability preventing them from ascending stairs, mobility itself becomes an exhausting and uncomfortable experience. Their existential situation is consistently filled with ‘fatigue’, inevitably encountering discomfort. The fundamental element constituting their experience is precisely fatigue. In other words, the staircase for a person with disabilities is essentially an object experienced in existential fatigue. Therefore, an essential understanding of people with disabilities can be determined from their existential fatigue. The spatial experience of people with disabilities is transcendental “fatigue.”

Understanding the essence is important because it deepens the understanding of the people who suffer from the disease. Phenomenological qualitative research differs from a simple descriptive research because of its eidetic approach. The phenomenological static investigation focuses on the essence. The essence is not something that is suddenly recognized without any context. To perceive the essence means to describe the phenomena of experience and to grasp them by reducing what is described with intentional acts. Husserl argues that in the change of attitudes, essence or “eidos” can be grasped through intuition (Husserl, 1977, p. 64).Footnote 10 The intuition of the essence proceeds from the object and examines the various aspects of the object in the imagination called “free variations” and grasps a unified quality that is revealed through this process. In examining the diverse elements constituting experiences and connecting common elements in continuous unity identified from the elements, Husserl asserts the essence of experience can be perceived. Phenomenology can extract universals through intentional acts. This is the method of static phenomenological analysis. With this investigation, Husserl’s phenomenological investigation aims “to grasp the structural essences of experience” (Moustakas, 1994, p. 35). This demonstrates the potential harmony between qualitative inner experiences and quantitative universals.

Understanding disease through phenomenological methods

The subjective method consists of considering various experiences as facts identifiable by experience and identifying them. The subjective experiential understanding is fundamentally different from the phenomenological understanding as it does not involve intentional acts for consideration. Phenomenology goes on to the method of “intuition of essence” to find the objectivity that the phenomenological approach understands and that is different from mere natural attitude. Phenomenological research explains the essence of the various experiences that are descriptively revealed. As qualitative research, phenomenological exploration can be divided into two main categories based on its revelation of the essence: experiential research as phenomenological psychology (ERPP) and experiential research as transcendental phenomenology (ERTP), which identifies the fundamental foundation that constitutes these experiences from phenomenological attitudes. ERPP is the attitude of phenomenological psychology that describes diverse lived experiences of consciousness. ERTP is the attitude of transcendental investigation of phenomenology to gain an eidetic understanding of the object given by consciousness. It examines the fundamental possibilities and conditions of such conscious experiences. Each of them, in turn, is divided into two categories according to whether the eidetic reduction is exercised through intentional acts. To sum up, Husserl’s phenomenological research is divided into four categories: (1) Descriptive Experience Research as Phenomenological Psychology (DERPP), (2) Essential Experience Research as Phenomenological Psychology (EERPP), (3) Descriptive Experience Research as Transcendental Phenomenology (DERTP), and (4) Essential Experience Research as Transcendental Phenomenology (EERTP).

We can more easily understand the above phenomenological inquiry methods through the case presented by Toombs. According to Toombs, disease experiences, as phenomenological experiences, can be classified into “four levels” (Toombs 1990, pp. 230–237), as follows: Level One is “Pre-Reflective Sensory Experience,” Level Two is “Suffered Illness,” Level Three is “Disease,” and Level Four is “Disease State.” Level One through Level Three involves disease constituted by a patient’s experiences, while Level Four is an objectively conceptualized disease extracted from the patient’s experiences. Level One is a state in which unfamiliar experiences, painful experiences, and sensual discomfort of the body are intentionally felt without reflective awareness. Level Two is a state in which the pain of illness is reflectively felt and constituted—a state in which a space separate from the painful experience is perceived. To perceive a space means, for example, to evoke a particular specific intentional act toward the body, such as the eyes, the stomach, or the head. At Level Three, the disease is shared with other people. At this Level, the person experiencing the illness may share the suffering experienced with others. For example, a person who experiences pain from a lump in the breast is surprised to be diagnosed with breast cancer. At this Level, the person reflectively shares the pain from the disease and places significance on it. Finally, at Level Four, the disease is reproduced as a concept generally shared among doctors. The medical concepts analyzed and shared by physicians are understood as a common concept, separate from the patient who experiences the disease. At this Level, the disease is considered a factual object, independent of the patient. For example, a disease is described by facts, such as the destruction of brain cells or the reduction of white blood cells.

At Level Four, the disease is revealed from objective understanding and conceptually referred to without any relation to subjective experiences.Footnote 11 The factual objective understanding, of course, can be presented as an attitude toward understanding disease. However, experiences of disease can be identified at other levels. The disease experiences may vary according to the person’s experiences. Only emphasizing Level Four is no different than arguing for a natural attitude to understanding disease. We must also investigate the experiences leading from the Level One to Level Three. In this sense, we can never dismiss the disease experiences from Level One to Level Three. These facts point to the potential of phenomenological research on illness experience.

The importance of phenomenological research is shown in the perception of the essence identified in the descriptions of the various qualitative experiences. From phenomenological research methods, the disease experience levels are classified from the state of experiencing immediately intended suffering to identify essence perception through reflection. By describing diverse intended disease experiences as they are, we can conduct DERPP. Moreover, we can identify the essence that emerges from these descriptions using EERPP. Furthermore, we can investigate the factors that constitute the essence of experiences revealed by perceiving the essence on a factual basis through DERTP. From these lists, we can find a transcendental essence that constitutes the essence of the disease through the EERTP.

According to Toombs, for example, the transcendental essence of illness, secured by methods such as experiential research as transcendental phenomenology, is defined as “loss” (Toombs, 1987, p. 235). From the most fundamental dimension, illness causes the loss of human totality, certainty and control, freedom, and familiarity, and thus the loss of “integrity” for the sufferer. In a word, for Toombs, the essence of illness captured by the transcendental phenomenological method is “loss.” Loss is a common fundamental element in the experience of illness.

To understand the above-mentioned phenomenological research method, let us take the case of a “cold” as an example again. A cold, of course, is easily understood by its objective conceptual definition as a disease caused by a virus. As argued above, this is one perspective from which to understand the illness experience of a cold. We can use phenomenological, descriptive methods to gain a deeper understanding of the illness experience of a cold. In DERPP, a variety of experiences of a cold can be “listed”: mild fever, feeling fatigued, a runny nose, stuffy nose, or coughing. However, the cold experience can be understood differently in different contexts. To one, it can be experienced as a time to rest and take a day off; to another, it can be experienced as leading to fears of possible complications. Describing the diverse intentional experiences as facts of consciousness, we can define the “generals” of these listed experiences by an intuition of essence (static analysis). For example, A cold can be defined as a respiratory illness, a contagious disease, a signal calling for hygiene, cleanliness, and rest, or it can be feared because it is associated with death. Thinking more deeply, phenomenological inquiry can identify “transcendental conditions” that constitute the experience of a cold. For instance, it can highlight human finitude, vulnerability, culture, dietary habits, economic conditions, or religious beliefs. Finally, it can reduce the various cases that show up in the transcendental constitution and extract a basic “transcendental essence” from the listed transcendental constitutional elements. A cold can ultimately be an experience of “loss,” as Toombs analyzed, but it can also be understood as “resilience” (Carel, 2016, p. 140). If we look beyond the mental and physical state of the person experiencing the cold, we can also recall their environment and lifestyle habits as conditions for cold experiences, from which we can derive the most basic identified conditions. In other words, we can affirm the transcendental essence of the object, which is derived from intentional experience through reduction.

We must remember here that the defining essence of the person’s experience of illness promoted by phenomenological methods must be validated with “transparency” to be evaluated as a condition for understanding and constituting the normal world (Crowell, 2013, p. 89). For the person’s experience of illness to be used broadly in the lifeworld, the experiences listed and understood must be transparently validated and shared. The validated understanding of illness can be seen as a concept that many people agree upon and share, but it is also a case of “anomaly.” This is because it is a task to capture the general essence from a variety of experiences, and an experience that is not part of the definition of essence may pose problems in understanding the phenomenological analysis. With its emphasis on the intentional experience of the given object, the phenomenological inquiry does not exclude instances of an anomaly; rather, it understands diverse experiences or instances of an anomaly as indicative of “qualitative variation” (Steinbock, 1995, p. 245). Anomalous or atypical experiences expand the generalized understanding of objects and create “the possibility of a new normative meaning” (Steinbock, 1995, p. 245). It means that the essence of objects understood through reduction may be an “optimal” outcome for understanding and sharing the object, but the outcome can always be modified or changed. Phenomenology opens up various possibilities for understanding disease according to genetic analysis.

Anomalous experiences cannot be readily generalized or excluded. In phenomenological understanding, however, these experiences are not excluded or even presented as potential elements leading to the creation of a new understanding. While phenomenological methods of inquiry seek to perceive the essence of transcendental construction through reduction, they also accept the diversity of experiences and seek to expand the horizon of understanding the object for inquiry. Because the phenomenological genetic analysis focuses on the point of view of continuous becoming. The phenomenological exploration methods described so far are summarized in Table 1.

Table 1 Phenomenological research.
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From the point of view of explaining the meaning revealed as intuition of the essence of qualitative experience, phenomenological methods of disease research are significant in that they go beyond explaining the understanding of disease by merely factual objective methods and examine the patient’s experience in a holistic context. Considering the patient’s existential experience cannot lead to a forced view of illness based on an objective understanding of patients. The multifaceted qualitative exploration of illness, experienced as the object given to consciousness, is associated with an open attitude towards suffering people. It reveals a problem with the attitude of defining disease only by whether there is a lesion identifiable by objective facts. As a notable example advocating for anti-psychiatry, one can consider Thomas S. Szasz. He dismissed psychiatry as “alchemy” or “astrology” (Szasz, 2010, p. 1) because no objective lesions were found that indicated a neurological abnormality. It tends to deny the diverse experiences of disease and the essential insights secured from them. His rejection of psychiatry because mental illness is neither objectively justified nor quantitatively confirmed is based on a lack of understanding of the multifaceted condition experienced in the intentional relationship of subject and object. For example, we do not consider the love of our parents or lovers as fantasy or fiction, even if it is not explicitly revealed as an objective fact in real life. By experiencing love directly, we can discover the essential meaning of the love we experience.

Since Husserl’s phenomenological research defines the diversity of qualitative meaning and the nature of disease, it overcomes the problem of mere natural attitude views and the relative issue of subjective experiences. Moreover, it establishes the norms for understanding illness through a diverse analysis of experience and understands the diversity of experience under openness. To reiterate: Husserl’s methods for exploring essence are always carried out with an open attitude. Husserl says essence is an “open undetermined horizon” and also “a realm of endless accessibilities,” and, thus, no person can fathom its infinity (Husserl, 1999a, p. 131). The being understood by experience can be changed by various aspects. The person who is on a certain horizon under different conditions should consider the possibility that the validity of the phenomenological understanding of the essence can always be modified. It is not to say that phenomenological exploration is finished with relativism. Transcendental phenomenological research presents the possibility of an “understanding” that is generally shared as the optimal outcome (with static and genetic analysis), and yet it leads to a constructive openness out of new validity that can be backed up by qualitative experience and does not lapse into dogma (genetic analysis). In this regard, phenomenology criticizes an understanding of mental illness that solely relies on the DSM-5 standard. The knowledge of mental disorders based on the dogmatic manual in the clinical inference process often fails to adequately capture the complicated situations of patients and the rich content of their experiences. Clinical diagnoses, according to the manual, may either diminish or exaggerate the patient’s experience. Anna Drożdżowicz criticizes the standardized DSM for creating a “lack” of “specificity” and “effectiveness” in mental illness and for creating a simplistic understanding of mental illness by producing “poorly standardized categories” (Drożdżowicz, 2020, pp. 686–687). Josef Parnas criticizes the DSM “shut off discussion” of productive features related to mental disorders (Parnas and Sass, 2015, p. 239). In capturing universals from diverse experiences, however, the phenomenological exploratory methods help to search for “the better” consistently for people with illness experiences (Svenaeus, 2019, pp. 467–468). Phenomenological research is a project to discover the dynamic meaning of essence.

Conclusions

The essence of Husserl’s phenomenological experiential research methods is realized in other aspects through data analysis along with data collection. In contrast to the mere objective stance, phenomenological experiential research discovers the intentional meaning of the experienced objects. It aims to clarify the essential significance of the objects by reflecting the transcendental reduction. Husserl’s transcendental inquiry is similar to Bruce G. Link and Jo Phelan’s search for “the fundamental cause of diseases” (Link and Jo, 1995). The many complex causal relationships affecting disease and health can never be simplified. Finding the fundamental cause involves a comprehensive approach to the disease’s social, economic, and environmental factors. This allows us to understand the buffering effect various factors have on health and disease. In particular, it identifies the various environmental and cultural causes of disease and reminds us of the importance of social, economic, and political participation. By uncovering the fundamental causes of diseases, phenomenological transcendental analysis of experiential diversity traces the essential roots of the disease experience.

In terms of phenomenological exploration methods, disease is significant because it offers a new perspective and understanding of our lives. Phenomenological research explores qualitative aspects experienced in different ways, illuminating the different types and essences of the object personalized through illness experiences. Phenomenological research overcomes the problems of subjective relativism by applying eidetic reduction and going beyond the biased exploratory methods. It means the phenomenological exploration criticizes the medicalization that emphasizes only the simple understanding and leads to taking note of the different qualitative elements of the experiences that could have been isolated. It is important to define the essence of the aspects as well as the aspects of the experiences of illness because such exploration is helpful for medical fields that comprehend the diverse experiences of patients from a broader perspective. This phenomenological research has practical significance for understanding disease. For example, the different aspects of illness experience revealed by phenomenological analysis prevent a biased understanding of illness. Based on an understanding of the multiple experiences of illness, phenomenological methods of inquiry lead patients to reexamine their problems and explore the various aspects of the patient’s experience about treatment. Consistent with today’s need for advanced precision medicine, phenomenological understanding of disease points in a direction that moves away from mechanically standardized clinical care and instead offers diversified medical services with tailored treatments optimized for the patient. Thus, disease analysis through phenomenological research helps in the collection of health and medical Big Data to set standards for a variety of examples. In addition, phenomenological research can be used in the study of legal, ethical, and regulatory norms using health and medical data. Considering all the discussions, the future value of phenomenological research can be regarded as substantial. It is true that the study of illness experience as a disciplinary field still requires additional discussion and empirical verification. In this sense, phenomenological research must be a task to be pursued further.