In 2015, doctors in Germany reported the extraordinary case of a woman who suffered from what has traditionally been called “multiple personality disorder” and today is known as “dissociative identity disorder” (DID). The woman exhibited a variety of dissociated personalities (“alters”), some of which claimed to be blind. Using EEGs, the doctors were able to ascertain that the brain activity normally associated with sight wasn’t present while a blind alter was in control of the woman’s body, even though her eyes were open. Remarkably, when a sighted alter assumed control, the usual brain activity returned.

This was a compelling demonstration of the literally blinding power of extreme forms of dissociation, a condition in which the psyche gives rise to multiple, operationally separate centers of consciousness, each with its own private inner life.

Modern neuroimaging techniques have demonstrated that DID is real: in a 2014 study, doctors performed functional brain scans on both DID patients and actors simulating DID. The scans of the actual patients displayed clear differences when compared to those of the actors, showing that dissociation has an identifiable neural activity fingerprint. In other words, there is something rather particular that dissociative processes look like in the brain.

There is also compelling clinical data showing that different alters can be concurrently conscious and see themselves as distinct identities. One of us has written an extensive treatment of evidence for this distinctness of identity and the complex forms of interactive memory that accompany it, particularly in those extreme cases of DID that are usually referred to as multiple personality disorder.

The history of this condition dates back to the early 19th century, with a flurry of cases in the 1880s through the 1920s, and again from the 1960s to the late 1990s. The massive literature on the subject confirms the consistent and uncompromising sense of separateness experienced by the alter personalities. It also displays compelling evidence that the human psyche is constantly active in producing personal units of perception and action that might be needed to deal with the challenges of life.

Although we may be at a loss to explain precisely how this creative process occurs (because it unfolds almost totally beyond the reach of self-reflective introspection) the clinical evidence nevertheless forces us to acknowledge something is happening that has important implications for our views about what is and is not possible in nature.

A 2018 paper by one of us posits that dissociation can offer a solution to a critical problem in our current understanding of the nature of reality. This requires some background, so bear with us.

According to the mainstream metaphysical view of physicalism, reality is fundamentally constituted by physical stuff outside and independent of mind. Mental states, in turn, should be explainable in terms of the parameters of physical processes in the brain.

A key problem of physicalism, however, is its inability to make sense of how our subjective experience of qualities—what it is like to feel the warmth of fire, the redness of an apple, the bitterness of disappointment and so on—could arise from mere arrangements of physical stuff.

Physical entities such as subatomic particles possess abstract relational properties, such as mass, spin, momentum and charge. But there is nothing about these properties, or in the way particles are arranged in a brain, in terms of which one could deduce what the warmth of fire, the redness of an apple or the bitterness of disappointment feel like. This is known as the hard problem of consciousness.

To circumvent this problem, some philosophers have proposed an alternative: that experience is inherent to every fundamental physical entity in nature. Under this view, called “constitutive panpsychism,” matter already has experience from the get-go, not just when it arranges itself in the form of brains. Even subatomic particles possess some very simple form of consciousness. Our own human consciousness is then (allegedly) constituted by a combination of the subjective inner lives of the countless physical particles that make up our nervous system.

However, constitutive panpsychism has a critical problem of its own: there is arguably no coherent, non-magical way in which lower-level subjective points of view—such as those of subatomic particles or neurons in the brain, if they have these points of view—could combine to form higher-level subjective points of view, such as yours and ours. This is called the combination problem and it appears just as insoluble as the hard problem of consciousness.

The obvious way around the combination problem is to posit that, although consciousness is indeed fundamental in nature, it isn’t fragmented like matter. The idea is to extend consciousness to the entire fabric of spacetime, as opposed to limiting it to the boundaries of individual subatomic particles. This view—called “cosmopsychism” in modern philosophy, although our preferred formulation of it boils down to what has classically been called “idealism”—is that there is only one, universal, consciousness. The physical universe as a whole is the extrinsic appearance of universal inner life, just as a living brain and body are the extrinsic appearance of a person’s inner life.

You don’t need to be a philosopher to realize the obvious problem with this idea: people have private, separate fields of experience. We can’t normally read your thoughts and, presumably, neither can you read ours. Moreover, we are not normally aware of what’s going on across the universe and, presumably, neither are you. So, for idealism to be tenable, one must explain—at least in principle—how one universal consciousness gives rise to multiple, private but concurrently conscious centers of cognition, each with a distinct personality and sense of identity.

And here is where dissociation comes in. We know empirically from DID that consciousness can give rise to many operationally distinct centers of concurrent experience, each with its own personality and sense of identity. Therefore, if something analogous to DID happens at a universal level, the one universal consciousness could, as a result, give rise to many alters with private inner lives like yours and ours. As such, we may all be alters—dissociated personalities—of universal consciousness.

Moreover, as we’ve seen earlier, there is something dissociative processes look like in the brain of a patient with DID. So, if some form of universal-level DID happens, the alters of universal consciousness must also have an extrinsic appearance. We posit that this appearance is life itself: metabolizing organisms are simply what universal-level dissociative processes look like.

Idealism is a tantalizing view of the nature of reality, in that it elegantly circumvents two arguably insoluble problems: the hard problem of consciousness and the combination problem. Insofar as dissociation offers a path to explaining how, under idealism, one universal consciousness can become many individual minds, we may now have at our disposal an unprecedentedly coherent and empirically grounded way of making sense of life, the universe and everything.

The views expressed are those of the author(s) and are not necessarily those of Scientific American.

Most recently the author of The Idea of the World: A Multi-disciplinary Argument for the Mental Nature of Reality, Bernardo Kastrup has a Ph.D. in philosophy (ontology, philosophy of mind) and another in computer engineering (reconfigurable computing, artificial intelligence). He has worked as a scientist in some of the world's foremost research laboratories, including the European Organization for Nuclear Research (CERN), and authored many academic papers and books on philosophy and science. For more information, freely downloadable papers, videos, etc., please visit www.bernardokastrup.com.

Adam Crabtree is on the faculty of the Centre for Training in Psychotherapy, Toronto. He is a clinician who has treated many cases of severe forms of DID overs the past 30 years. He has written extensively about the history of psychodynamic psychotherapy from the time of Franz Anton Mesmer to the present, tracing the development of ideas about dissociation in the West, particularly in his book From Mesmer to Freud: Magnetic Sleep and the Roots of Psychological Healing (1993).

Edward F. Kelly is a professor in the Division of Perceptual Studies (DOPS), a research unit within the Department of Psychiatry and Neurobehavioral Sciences at the University of Virginia Medical School. He served as lead author of Irreducible Mind (2007) and Beyond Physicalism (2015), which systematically explore empirical and theoretical topics related to the primacy of mind in nature. His research interests currently focus on intensive neuroimaging studies of altered states of consciousness in exceptional subjects of various kinds.