The Morrígan

O Morrigan, we call your name
Across the dusty years.
You speak to us, of blood and lust. 


The primary themes asAlso known as the Morrigu, “great queen” or “phantom queen,” the Morrigan has the ability to change her shape and take the form of a crow. Yet another name for her is Badb, meaning “battle-crow” though it’s sometimes translated as “air-demon.” The motif of animal transformation is known as the feth fiada, (“master spell” or “master mist”) and is a frequently recurring theme in Irish mythology. The Morrigan takes part in “The Táin Bó Cúailnge,” or “The Cattle-Raid of Cooley,” throwing in her lot as she sees fit. She has a connection to Cúchulainn, though her exact feelings toward him are unclear, and she takes great interest in his successes and failures; at his death, she and her sisters perch on his shoulders in crow form. The Morrigan is known as a triple goddess figure, taking the forms of maiden, mother and crone at different points throughout the myths. At the end of “The Second Battle of Mag Tured,” she predicts a grim future.

Associated with the Morrígan are battle, strife, and sovereignty. She sometimes appears in the form of a crow, flying above the warriors, and in the Ulster Cycle she also takes the forms of an eel, a wolf and a cow. She is generally considered a war deity comparable with the Germanic Valkyries, although her association with a cow may also suggest a role connected with wealth and the land.

Part 2: Psyche and Matter: The Connections

Modern science may have brought us closer to a more satisfying conception of this relationship [between psyche and physis] by setting up, within the field of physics, the concept of complementarity. It would be most satisfactory of all if physis and psyche could be seen as complementary aspects of the same reality.[12] – Wolfgang Pauli


Microphysics is feeling its way into the unknown side of matter, just as complex psychology is pushing forward into the unknown side of the psyche. Both lines of investigation have yielded findings which can be conceived only by means of antinomies, and both have developed concepts which display remarkable analogies. If this trend should become more pronounced in the future, the hypothesis of the unity of their subject-matters would gain in probability. Of course there is little or no hope that the unitary Being can ever be conceived, since our powers of thought and language permit only of antinomian statements. But this much we do know beyond all doubt, that empirical reality has a transcendental background.[13] – C. G. Jung

In attempting to understand the deepest levels of reality, it is wise to take note of Jung’s observation that our concepts are imperfect instruments, and that any conceptual representations we may form of these regions of reality will likely involve antinomies, and should be taken as being essentially symbolic rather than literal. For example, progress in the conceptual understanding of the nature of quanta was accomplished by acknowledging the principle of complementarity, which states that mutually exclusive sets of concepts must be used to completely characterize quantum phenomena in all their aspects. As Marie-Louise von Franz tells us, Jung recognized that this principle of complementarity applied to psychology as well as to physics:

Bohr’s idea of complementarity is especially interesting to Jungian psychologists, for Jung saw that the relationship between the conscious and unconscious mind also forms a complementary pair of opposites.[14]

The analogy suggested here is that the wave-particle complementarity in quantum physics parallels the unconscious-conscious complementarity in psychology. Indeed, just as the wave is the unobserved aspect of the quantum and the particle is the observed aspect, so the unconscious is the unobserved aspect of the psyche and the conscious is the observed aspect. Moreover, the wave is continuously spread throughout space, while the particle has a limited location. Similarly, Jung states that

The area of the unconscious is enormous and always continuous, while the area of consciousness is a restricted field of momentary vision.[15]

The analogy goes even further. The quantum wave function represents probabilities, as contrasted to the actualized particle. Similarly, the archetypal structures of the unconscious represent fundamental potentialities of psychic manifestation, while conscious contents are actualizations of these potentialities. As von Franz explains,

What Jung calls the archetypes…could just as well be called, to use Pauli’s term, “primary possibilities” of psychic reactions.[16]

This suggests that the unus mundus behind both psyche and matter is also a continuous world of potentiality. Jung elaborates:

The common background for microphysics and depth-psychology is as much physical as psychic and therefore neither, but rather a third thing, a neutral nature which can at most be grasped in hints since in essence it is transcendental. The background of our empirical world thus appears to be in fact an unus mundus. … The transcendental psychophysical background corresponds to a `potential world’ in so far as those conditions which determine the form of empirical phenomena are inherent in it.[17]

The following table summarizes the correspondence between complementary principles in psyche and matter:

TRANSCENDENT unconscious contents
unmanifest archetypes
unobserved quanta
wave functions
EMPIRICAL conscious contents
manifest images
observed quanta

Extending the analogy between psyche and matter further, physicist Victor Mansfield points out a similarity in the manner in which potentialities are transformed into actualities in the two realms:

In physics the irreversible measurement process transforms the potentialities into actualities. What is the corresponding psychic function that transforms `the potential world…’ into the world of multiplicity? It is reflective consciousness, the association of knowing with the ego, which makes the empirical world possible and brings the transcendental into the empirical world of multiplicity. The primordial unity of the unus mundus is shattered by reflective consciousness-a point agreed upon in most mystical traditions.[18]In quantum mechanics it’s only when an individual observes that an acausal spacetime event manifests. Our participation through measurement generates acausality. Analogously, when a unique center of consciousness, a specific individual, actualizes a possibility in the unus mundus, acausality enters our world. Introducing a particular perspective, a finite center of consciousness, inevitably brings acausality into the transition from possibilities to actualities.[19]

Similarly, Jung has made a correspondence between the indeterminacy inherent in quantum measurement and the attempt to consciously determine unconscious contents:

Any attempt to determine the nature of the unconscious state runs up against the same difficulties as atomic physics: the very act of observation alters the object observed. Consequently, there is at present no way of objectively determining the real nature of the unconscious.[20]

It should be pointed out here that Jung’s characterization of quantum measurement requires clarification. The quantum measurement does not alter the actual properties of the object being observed since these properties do not have determinate existence prior to measurement. More accurately, the measurement is the occasion for the determination of the actual properties of the object. There is thus a spontaneity that enters nature in quantum measurement. Similarly, the manifestation of unconscious contents within consciousness also has an element of spontaneity, insofar as the particular conscious image manifesting an archetype is not completely determined by previous conscious contents. This type of spontaneity is especially evident in synchronicity.

Although synchronicity phenomena and quantum phenomena have certain similarities, there are also important differences. Consider, for example, nonlocal correlations that have been experimentally observed between two separated quantum events. Like synchronicity, the observed properties of the observed quanta have an element of spontaneity in their manifestation, and the correlations between the two quanta are not due to efficient causation between the two particles. Quantum nonlocality phenomena differ from synchronicity, however, because two quantum events are both events in the outer physical world. Synchronicity, on the other hand, is necessarily a connection between an inner event and an outer event, bridging psyche and matter, and thus pointing to the unus mundus. This brings us to perhaps the most important distinction between the two phenomena, which relates to the inner psychological meaning that is essential to synchronicity. As explained by Mansfield,

In the quantum phenomenon…there is no meaning involved. …In contrast, when an archetype manifests in a synchronicity experience, meaning is the critical point.[21]

Thus, synchronicity essentially involves the manifestation of meaning in the sense of an unconscious compensation that serves an individual’s process of individuation toward wholeness. Nonlocal correlations between quanta, in contrast, are connections between two physical events, and do not involve a manifestation of inner psychological meaning.

Another more subtle distinction between synchronicity and quantum nonlocality is that the quantum correlations are scientifically repeatable and predictable, while synchronicity phenomena appear to be almost entirely spontaneous and unpredictable. A closer psychological analog to quantum nonlocality is parapsychological phenomena. Mansfield elaborates:

Parapsychological phenomena are an example of general acausal orderedness, but not of synchronicity, which I strictly define as an acausal exemplification of meaning in the inner and outer world. Parapsychological phenomena are acausal since no energy or information exchange seems responsible for the correlations measured, but they lack the meaning associated with synchronicity. Furthermore, parapsychological phenomena, like similar quantum phenomena, are “constant and reproducible”…. This reproducibility is in further contrast to the unique and unpredictable nature of the more narrowly defined synchronicity.[22]

Jung considered synchronicity to be a special case of “general acausal orderedness,” which refers to forms of order that cannot be understood in terms of efficient causality or physical determinism. For example, the causal ordering of physical phenomena according to the deterministic laws of classical physics are not acausal orderedness. Nonlocal quantum correlations, however, are an instance of acausal orderedness manifest in the physical world. Synchronicity is also an example of a specific form of acausal orderedness which involves a meaningful connection between inner and outer events, exhibiting a manifestation of the depths of the unus mundus prior to divisions between psyche and matter.

From the above comparisons between physics and psychology, we can infer that the unus mundus is a domain of unified potentiality beyond the limitations of spatial separation and causal relationships in time. Although it is prior to many structures and limitations of manifest phenomena, this domain has orderedness and meaning–it is a domain of Logos. As a result, the deep structure of the unus mundus is perhaps most appropriately represented using the symbols of mathematics. As Jung explains,

Number helps more than anything else to bring order into the chaos of appearances. It is the predestined instrument for creating order, or for apprehending an already existing, but still unknown, regular arrangement or “orderedness.” It may well be the most primitive element of order in the human mind.[23]

And von Franz amplifies Jung, pointing out that mathematical order is common to both psychological and physical domains:

The deepest and most clearly distinguishable archetypal factor, which forms the basis of psycho-physical equivalence is, the archetypal patterns of natural numbers. . . . In respect to mathematical structure, the acausal orderedness in matter is of the same kind as that in the psyche and each is continually reflected in the other.[24]As an archetype, number becomes not only a psychic factor, but more generally, a world-structuring factor. In other words, numbers point to a background of reality in which psyche and matter are no longer distinguishable.[25]

If indeed number, and mathematics in general, reflects the order of the unus mundus, this would explain the profound mystery of how it is that mathematics, which is a phenomenon of the mind, should prove so remarkably effective in representing the physical world. This mysterious harmony between psyche and matter is implicitly present at the foundation of all physics, and testifies to the Pythagorean roots of modern science. The Pythagoreans, however, viewed mathematics as much more than a mere language of quantity. For them numbers were symbols charged with archetypal meaning. The modern view of numbers, in other words, acknowledges only the quantitative aspect of numbers and ignores their aspect as quality and meaning. Moreover, von Franz points out that numbers are not merely static forms, but also represent vibrational energies (as the Pythagoreans recognized in the intimate connection between numbers and musical tones):

Since today we see processes everywhere rather than structures or static orders, I have also proposed seeing numbers in this perspective–as rhythmic configurations of psychic energy.[26]From time immemorial number has been used most frequently to bridge the two realms because it represents the general structure of psychic and physical energy motions in nature and therefore appears, as it were, to provide the key to the mysterious language of unitary existence, particularly in its aspect of meaning (Tao).[27]

Like quanta, numbers have two complementary aspects, both of which are required if we are to more completely understand them. They have both quantitative and qualitative aspects, both static and dynamic aspects. It is through this double aspect of number, von Franz claims, that we can see their importance as a bridge between psyche and matter:

This complementary double aspect of number (quantity and quality) is in my opinion the thing which makes it possible for the world of quantity (matter) and of quality (psyche) to interlock with each other in a periodical manner.[28]

Although von Franz associates matter with quantity, and psyche with quality, it should be noted that material vibrations, as with musical strings, are experienced as qualities or quantities depending on which aspect of the phenomenon we choose to isolate. Moreover, mathematical ideas experienced in the psyche have aspects of quantity as well as quality. Thus, it appears more appropriate to identify the qualitative aspect of number with its more subtle, vibrational component (whether physical or psychic) and the quantitative aspect of number with its more concrete, discrete component. The table of complementary aspects can then be amended to include the elements of number, as follows:

TRANSCENDENT unconscious contents
unmanifest archetypes
numerical psychic qualities
unobserved quanta
wave functions
numerical physical qualities
EMPIRICAL conscious contents
manifest images
distinct numerical quantities
observed quanta
distinct material quantities

In any case, the key to the unity of psyche and matter, and to understanding the unus mundus, essentially involves the nature of number. There was at least no doubt as to this point for von Franz:

In the last analysis, the mystery of the unus mundus resides in the nature of number.[29]

The understanding suggested by the above comparisons between structures in physics and psychology, therefore, is that physis and psyche are aspects of the same reality, with mathematics as a key archetypal core of both. However, we should note that the complementarity between psyche and matter (i.e., the two columns of the table above) appears distinct from the complementarity within psyche and matter (i.e., the two rows of the table above), so we should be careful not to confuse the two.

According to von Franz, the physicist David Bohm arrived at a similar understanding of the unified ground of psyche and matter:

David Bohm also presupposes the existence of an “ocean of energy” as the background of the universe, a background that is neither material nor psychic, but altogether transcendent. . . . Ultimately, it corresponds exactly to what Jung calls the unus mundus, which is situated beyond the objective psyche and matter and which also is situated outside space-time.[30]

Bohm’s “ocean of energy” is a deep part of the implicate order of reality, which is distinguished from the explicate order. Typically, we are conscious of only these explicate features of reality, while the implicate features form an unconscious background. Bohm’s idea of the implicate order thus normally corresponds to the unconscious, while the explicate order corresponds to the conscious. He summarizes the idea of the implicate order as follows:

The essential feature of this idea was that the whole universe is in some way enfolded in everything and that each thing is enfolded in the whole. From this it follows that in some way, and to some degree everything enfolds or implicates everything, but in such a manner that under typical conditions of ordinary experience, there is a great deal of relative independence of things. The basic proposal is then that this enfoldment relationship is not merely passive or superficial. Rather, it is active and essential to what each thing is. It follows that each thing is internally related to the whole, and therefore, to everything else. The external relationships are then displayed in the unfolded or explicate order in which each thing is seen, as has already indeed been indicated, as relatively separate and extended, and related only externally to other things. The explicate order, which dominates ordinary experience as well as classical (Newtonian) physics, thus appears to stand by itself. But actually, it cannot be understood properly apart from its ground in the primary reality of the implicate order.[31]

Reality is a flowing of this whole (or, in Bohm’s terms, a holomovement) with varying degrees of implication and explication. For Bohm, reality includes both psyche and matter, and the idea of the implicate order applies to mind as well as to matter, thus providing a link between the two:

We are suggesting that the implicate order applies both to matter…and to consciousness, and that it can therefore make possible an understanding of the general relationship of these two, from which we may be able to come to some notion of a common ground of both.[32]

And von Franz agrees:

These terms of Bohm’s can be applied quite well to the ideas put forward by Jung in his area of research. For example, in that case the archetypes can be understood as dynamic, unobservable structures, specimens of the implicate order. If, on the other hand, an archetype manifests as an archetypal dream image, it has unfolded and become more “explicated.” If we go on to interpret this image using Jung’s hermeneutic technique. . . that image would “explicate” and unfold still further.[33]

It is significant to note that, as von Franz implies, unconscious content can be explicated to various degrees, making it more conscious. This suggests that there is not a clear distinction between the conscious and the unconscious, but rather a continuum. Indeed, Jung explicitly says just this:

Conscious and unconscious have no clear demarcations, the one beginning where the other leaves off. …The psyche is a conscious-unconscious whole.[34]

In other words, the psyche is a unity or whole containing an explicate region of consciousness that is neither fixed nor ultimately distinguishable from the whole. According to Bohm, however, consciousness is not necessarily coincident with the explicate order, since we can become directly aware of these subtle flowing aspects of the implicate order taking place in the background of the more concrete and explicit aspects of our experience. Nevertheless, our consciousness is often habitually fixated on the more explicit content. As Bohm explains:

One reason why we do not generally notice the primacy of the implicate order is that we have become so habituated to the explicate order, and have emphasized it so much in our thought and language, that we tend strongly to feel that our primary experience is of that which is explicit and manifest. However, another reason, perhaps more important, is that the activation of memory recordings whose content is mainly that which is recurrent, stable, and separable, must evidently focus our attention very strongly on what is static and fragmented. This then contributes to the formation of an experience in which these static and fragmented features are often so intense that the more transitory and subtle features of the unbroken flow…generally tend to pale into such seeming insignificance that one is, at best, only dimly conscious of them.[35]

Bohm seems to point out possibilities of consciousness that were not acknowledged by Jung. In particular, for Jung the unconscious is a transcendental region of reality that we can never know directly. Thus, we only know the unconscious indirectly and imperfectly from the images and other concrete manifestations that surface in consciousness. According to Bohm, however, although consciousness is habitually fixated on the explicit surface manifestations rising up from deeper implicate levels of the psyche, it is nevertheless possible to become directly conscious of these implicate orders of reality–orders of reality that Jung assumed to be forever unconscious. Thus, while Jung remains correct with regard to consciousness that is fixated exclusively on explicit orders, his statements must be qualified to allow for a consciousness that develops the capacity to be aware of subtler levels of manifestation. Such a consciousness will have the capacity for direct awareness of contents that previously would be considered transcendent, unconscious, and only indirectly knowable by inference from more explicit and concrete manifestations. The implication is that we cannot maintain a rigid or ultimate distinction between the transcendent and empirical, between the archetypes and their manifestations, or between the implicit order and the explicit order. Rather, the explicit is imbedded in and essentially integrated with the implicit, with a continuum of degrees of enfolding and unfolding uniting the two. Similarly, the manifested images of the archetypes cannot ultimately be separated from the archetypes, but must be seen as their manifested aspects that are inseparable from the archetypes in their potential-actualized wholeness.

An Integral View of Psyche and Matter

Surprisingly, our exploration into the unity of psyche and matter has revealed an essential unity between the implicate and explicate aspects of each. That is, the unity is as much vertical within each realm as horizontal between them. In retrospect, we can see why this must be so, since the separate empirical realms of psyche and matter cannot truly be united if this unity only resides in a transcendent realm that is absolutely divided from the empirical realms. We must have unity both vertically and horizontally. This combined vertical-horizontal integration can be illustrated by the following analogy from physics. Prior to Einstein, energy and matter were thought to be separate and autonomous empirical phenomena. This separation of energy and matter is reflected in the two classical conservation laws: the conservation of energy and the conservation of mass. After Einstein, however, the distinction between matter and energy was no longer absolute, and it was recognized that mass and energy are separate aspects or manifestations of an underlying unity of mass-energy (mathematically represented as a 4-dimensional energy-momentum vector). The old conservation laws were thus subsumed within a new law: conservation of mass-energy.

TRANSCENDENT 4-dimensional energy-momentum vector
1 component of the energy-momentum vector 3 components of the energy-momentum vector

In this analogy, the duality of mass and energy is horizontal, because these are two phenomena manifesting on the same empiric plane. They manifest as relatively autonomous phenomena as long as relative motions are negligible in comparison with the speed of light. In Einstein’s theory, matter and energy are understood as the empirical manifestations of a unified reality (i.e., the energy-momentum 4-vector). Energy corresponds to one component of the 4-dimensional vector, while mass corresponds to the other three components. Interestingly, however, the vector acts as a whole, with the result that its mass and energy components can be mixed in various ways when the vector manifests (is “projected”) into a particular empirical reference frame. This mixing betrays the unity of energy and mass within this transcendent realm. One can visualize the essence of this mixing by imagining two spotlights shining on an upright pole from different angles, projecting two shadows on the floor. One shadow is the analog of energy, the other is the analog of mass. If we tilt the pole away from its upright orientation, the lengths of the two shadows (i.e., the observed mass and energy) will change, while the length of the pole itself stays constant.

The above analogy illustrates how we might understand how psyche and matter can manifest as relatively autonomous realms that are nevertheless mysteriously coordinated by virtue of their common origins deep within the unus mundus. Like the conservation laws of matter and energy, psyche and matter manifest in such a way that the transformations of one are in many ways independent of the other. Our thoughts, for example, normally appear to operate with relative independence from the transformations taking place in most of the physical world. Conversely, the transformations of matter in the universe are not normally altered by our thoughts. Yet, certain anomalous phenomena such as synchronicity sometimes burst forth unexpectedly, hinting at some mysterious unity of psyche and matter. And at deeper, subtler, and more implicate levels of manifestation, the connections become increasingly evident, such as the archetypal patterns of number that are essential to the orderedness in both realms.

Thus, if consciousness becomes sufficiently subtle to see the implicate aspects of both psychic and physical phenomena, their unity in a common source can be directly experienced and not merely inferred indirectly from diverse concrete particulars. This implies the necessity for an expanded epistemology for physics, psychology, and knowledge in general that takes us well beyond the forms of knowing that are limited to only the most explicit orders of reality. For truly integrative knowledge, we must expand and deepen our capacities of consciousness. Otherwise, an integral theory will be nothing more than a pleasing speculative construct based on explicit contents that have emerged from the deeper levels. In short, if we are really to know the unitive depths of Bohm’s ocean of energy, we must allow ourselves to sink down into them, and not merely watch the surface phenomena that merely hint at what is below. The unconscious calls us into its depths.

We can define the unconscious in the most general sense as the domain of all things that are indirectly known, posited, or presumed to exist outside of the present conscious awareness but that have an influence on the contents of conscious awareness. The unconscious is the realm of the unmanifest (relative to our present consciousness). Typically, our consciousness is fixated on the explicate order, while the implicate order remains largely unconscious. In some cases, however, consciousness may move into the depths of the implicate order. In addition to both personal and impersonal psychic contents, these depths also include both personal and impersonal physical contents. For example, although the dishes inside the dishwasher are presumed actually to be there, they are in fact outside of present conscious awareness, and are in the domain of the unconscious (relative to our present consciousness). Because they are in principle accessible to anyone, they are part of a collective unconscious. What we conventionally call objective physical reality, therefore, can be viewed as a region of the collective unconscious that is partially presented to each of us in a unique way during our waking consciousness. The structures of this region of the unconscious are known as the physical laws, since they determine the lawful manner in which this region behaves and evolves. The so-called objective world is in fact part of the unconscious and is only glimpsed indirectly through its projections into conscious awareness. For example, if I open the dishwasher, what appears in consciousness is a visual image of a plate viewed from a particular perspective. The plate in itself is not seen. It is not in consciousness. Only a projection of the plate’s visual image is seen. The plate itself (its implicate aspect) remains a transcendental idea posited to exist outside of consciousness. The plate is therefore still largely implicate in the unconscious, even when I am looking at an explicate aspect of it. Only an image of the plate actually arises in consciousness. Moreover, if my friend is looking as well, she will see a different image due to her different perspective. Neither one of us sees the plate in all its implicate totality, however. This is analogous to the fact that the universal implicate aspects of archetypes are not manifest in the explicate order, but their diverse explicate aspects manifest to us in dreams as particular symbolic expressions that vary from person to person.

The explicit archetypal contents that are generally accessible to us provide the basis for a collective understanding of a shared world. In the case of access via the physical senses, this collective understanding takes the form of the physical world. In the case of the mind, this collective understanding takes the form of psychological archetypes, transpersonal states of consciousness, mathematics, and so on. Insofar as the archetypes are not entirely unambiguous in their explicate manifestations, or manifest in ways that are influenced by cultural or personal factors, they allow us to create a multitude of interpretive frameworks for understanding and representing these objective worlds. Thus, for example, our inner experience of mystical states of consciousness may find expression in various different philosophical or religious systems, while our outer experience of physical phenomena may be understood in terms of distinct scientific paradigms. The development of physics involves the successive refinement of our shared understanding and explorations of deeper and deeper regions of these collectively accessible regions of outer experience. As our understanding penetrates to deeper levels of increasing subtlety, the representation becomes more universal and comprehensive, so that the structure of the nested representations within physics range from very general universal laws down through particular instances valid only for restricted domains of experience, to a specific quantitative numerical prediction for a given experimental arrangement. Our understanding is therefore provided with a depth that reaches from the multiple contents of explicate conscious awareness from many possible perspectives, down to the universal implicate depths that are common to all perspectives. A similar structure is present in mystical traditions, where the understanding links the particular experiential phenomena of an individual, up through intermediate levels common to certain types of individuals engaged in particular practices, to universal principles common to all individuals. Depth psychology is again similar, with experiential dream images and such related first to personal unconscious contents, and then to deep archetypal structures of a collective nature.

Note that each phenomenon contains within it aspects of all levels. The implicit aspects of a phenomenon may be known directly by a correspondingly subtle awareness. Alternatively, they may be unfolded by comparing and contrasting similar phenomena from many different perspectives, providing us with a more explicit understanding of the aspects that are particular to each phenomenon, and the aspects that are universal to all the similar phenomena.

It appears that at a very deep level there is no distinction between physical and psychic structures, and that these are, as it were, two perspectives we have on the same core reality. Thus, through comparison and contrast of physical and psychic phenomena, we can isolate the essence of this common core. It does seem clear, however, that one key feature of this core is its mathematical nature. (Note that this view contrasts with the notion that “physical” is a concrete level of reality, while “psychic” is a subtle level. Rather, they both have depths of subtlety that penetrate to the core of reality, and they both have a concrete surface that is immediately present in ordinary empiric consciousness. Thus mind cannot be reduced to matter, nor matter to mind. Both emerge as different aspects of a more fundamental ground.)

It should be kept in mind that, as Bohm points out, our access to these deep implicate levels is not necessarily limited to indirect access through correlation of diverse explicit contents with theoretical representations in order to infer their common core. It is also possible to directly access these implicate levels of reality that are normally considered unconscious. In other words, the unconscious can become conscious in two ways: indirectly through inference from explicit contents, or directly through an expansion of the range of consciousness into the more implicate levels of reality.

With the advance of physics and psychology, our theoretical understanding of the mystery beyond the range of our present consciousness is expanding to the point where we see hints of the identity of psyche and matter at deep levels. The evolution of consciousness that is explicating and integrating more of the unconscious appears to be bringing into an explicate unity an original implicate unity. This integrative theoretical understanding, however, is merely an attempt to conceptually hold together diverse fragmented contents that have emerged on the explicate level. Such a conceptual unity is at best a partial and imperfect representation of otherwise unconscious content, and we must be careful not to mistake this representation for the unconscious content itself, confusing our world of abstractions with concrete experience. Fundamentally, this mistake is the ignorance of the process of positing the existence of things beyond or outside our consciousness, and thus confusing our conscious representations of those things as being “things themselves” (such as when we imagine a material particle to have an objectively existing position). Because the conscious representation inevitably fails to correspond exactly with the unconscious reality, the confusion results in a distortion of our understanding of reality. Inevitably, reality (i.e., the unconscious portion of reality) manifests itself to consciousness in a way that contradicts this distortion. This unconscious compensation is then experienced as a crisis, and the anomaly is either integrated or denied. If it is integrated, a more comprehensive and accurate conscious representation of reality typically develops. If it is not integrated, the unconscious compensations will continue until they create sufficient cognitive crisis to result in a sacrifice of the distortion. In either case, because our representations can never perfectly mirror reality, the developmental process will continue. This whole process of development is based on the fundamental mistake of failing to recognize that our conscious representation of what is outside of our consciousness (i.e., the objective world) is an imperfect imaginative construct, and not an actual mirror of some real, objective reality.

If there is a recognition of the very process of positing the existence of things outside of consciousness through the confusion of the representation with the real, then any inaccuracy of our conscious representation is no longer a problem because it is never confused with reality in the first place. The spontaneous revelations of reality that do not fit into prior representational schemes are then experienced with delight, and are not met with resistance. In other words, it is recognized at the deepest level of our psyche that reality always has and always will infinitely transcend our representations of it. As a result, we are most in touch with reality when our experiences go beyond our representations of reality.

Quantum Physics, Depth Psychology, and Beyond Part 1.

Quantum Physics


The existing scientific concepts cover always only a very limited part of reality, and the other part that has not yet been understood is infinite. Whenever we proceed from the known into the unknown we may hope to understand, but we may have to learn at the same time a new meaning of the word `understanding’.[3] – Werner Heisenberg

The fundamental laws of quantum physics were discovered independently in 1925 by Werner Heisenberg and in 1926 by Erwin Schrödinger in response to puzzling experimental evidence that contradicted the fundamental concepts of classical physics. For example, electrons (which were previously thought to be particles) were found to exhibit properties of waves. Conversely, light (which was previously thought to be waves) was found to exhibit properties of particles. This confusion of classical distinctions between particles and waves was resolved by Niels Bohr’s principle of complementarity, according to which the wave and particle concepts are understood to be mutually exclusive but both necessary for a complete description of quantum phenomena.

A consequence of this wave-particle duality is that all matter has a wave aspect, and cannot be said to have a definite localized position at all times. Moreover, by virtue of their nonlocal wave properties, pairs of spatially separated particles sometimes exhibit nonlocal correlations in their attributes. Another consequence of the wave-particle duality is a corresponding duality between the unobserved and the observed. This duality raises puzzling questions regarding the nature of measurement in quantum mechanics: how is it that the wave suddenly changes into a particle, and how is this sudden transformation related to observation?

A deeper understanding of these subtle issues requires some basic understanding of the way quantum physics describes phenomena. According to quantum physics, the state of an unobserved quantum of matter or light (such as an electron or photon) is represented by a solution to Schrödinger’s wave equation. This solution is a quantum wave function y(x) whose intensity |y(x)|2 at any particular position x represents the probability of observing the quantum at that position. When the quantum is observed, however, it is seen to have a definite actual position, and the wave function no longer properly describes the quantum. Thus, when the quantum is unobserved, it is a nonlocal wave of probable positions; and when the quantum is observed, it is a particle having a definite localized position. As a result, both the particle and wave concepts are required to completely characterize a quantum: the particle concept is required to describe its particle-like behavior when observed, while the wave concept is require to describe its wave-like behavior when unobserved. The particle and wave concepts are called “complementary” descriptions because they are both needed to characterize the observed and unobserved aspects of any quantum, as illustrated in the following table.

wave functions
unobserved quanta
observed quanta

Although observation is evidently necessary to bring about the transition from possible to actual, the fundamental nature of observation in quantum theory remains somewhat mysterious. This problem of measurement derives from the fact that, prior to observation the quantum is described as being a nonlocal wave of probability spread throughout space, while after observation only one of the possible values is actualized. Thus, observation involves a discontinuous “collapse” (also called a “projection”) of the quantum wave function from a continuum of possibilities to a single actualized value. This projection, however, is an ad hoc element of the formalism, and is not a lawful transformation that is governed by Schrödinger’s wave equation. There is no explanation for how, when, or where this mysterious projection happens. Moreover, when the projection takes place, the laws of quantum physics do not predict which of the possible values will be actualized in any given observation, thus violating classical determinism and introducing an element of acausality and spontaneity into the theory at a fundamental level.

In a fundamental analysis of the quantum measurement process, John von Neumann argued that consciousness is required to explain the projection of the wave function from possibility to actuality. In particular, he reasoned that because all physical interactions are governed by Schrödinger’s wave equation, the projection that is associated with observation must be attributed to a non-physical consciousness that is not governed by physical law. According to von Neumann, this activity of consciousness only serves to cause the projection, and does not select or influence the particular value actualized. There is thus a spontaneity inherent in the projection that takes place in the transition from the unobserved to the observed.

Jungian Psychology

Since the stars have fallen from heaven and our highest symbols have paled, a secret life holds sway in the unconscious. …Our unconscious…hides living water, spirit that has become nature, and that is why it is disturbed. Heaven has become for us the cosmic space of the physicists, and the divine empyrean a fair memory of things that once were. But “the heart glows,” and a secret unrest gnaws at the roots of our being.[4] – C. G. Jung

The notion of the psychological unconscious was first extensively developed in Freud’s The Interpretation of Dreams, published in 1900, and further developed in his Three Essays on the Theory of Sexuality, published in 1905. In addition to the contents of our conscious awareness, Freud considered the psyche to also contain an unconscious region whose contents are hidden and cannot be directly observed. These unconscious contents, according to Freud, consist of previously conscious contents that have been repressed and forgotten. The unconscious is thus a kind of `skeleton closet’ containing personal psychological contents that were conscious in the past but then hidden away. Although they are no longer directly observable, these unconscious contents can be indirectly known through their effects on consciousness, such as their influence on our dreams. In Freud’s conception, the unconscious contains only personal psychic contents that were previously conscious, but then repressed, typically during childhood.

After studying with Freud, Carl Jung deepened and expanded Freud’s notion of the unconscious, most notably in his Psychology of the Unconscious, published in 1912, and his Archetypes of the Collective Unconscious, published in 1934. According to Jung, the unconscious contains, in addition to repressed personal contents, a deep and vast region of collective psychic contents, called the collective unconscious. In contrast to the personal unconscious contents that were previously conscious, the collective unconscious contents do not derive from previously conscious personal contents. Instead, the collective contents are innate and universal. In Jung’s words,

We have to distinguish between a personal unconscious and an impersonal or transpersonal unconscious. We speak of the latter also as the collective unconscious, because it is detached from anything personal and is common to all men, since its contents can be found everywhere, which is naturally not the case with the personal contents.[5]

Although the collective unconscious is present in the depths of each individual psyche, it is not subjective in the sense of being different from person to person. Because the collective unconscious is common to all individuals, it is objective in the sense that all individuals share these same deep psychic structures. As Jung writes,

The collective unconscious stands for the objective psyche, the personal unconscious for the subjective psyche.[6]

In short, the door to the unconscious does not open up to a skeleton closet, as Freud proposed, but opens up to a larger world beyond the walls of the conscious psyche.

It is important to note that between the personal and collective regions of the psyche there are various intermediate levels of depth, each having its share of universality and particularity. Jung explains:

In as much as there are differentiations as corresponding to race, tribe, and even family, there is also a collective psyche limited to race, tribe, and family over and above the “universal” collective psyche.[7]

The unconscious, in other words, is not divided into distinct personal and collective regions, but rather is a continuum with the personal and universal contents at each extreme. Jung’s most important contribution and his primary interest, however, is in the deeper regions of the collective unconscious, whose structures Jung calls archetypes. Like Plato’s Ideas, the archetypes of the collective unconscious are universal patterns that shape our experience of the world and provide it with common elements. Following Kant, however, Jung considers the archetypes as epistemological structures rather than independent ontological entities:

The collective unconscious, being the repository of man’s experience and at the same time the prior condition of this experience, is an image of the world which has taken eons to form. In this image certain features, the archetypes or dominants, have crystallized out in the course of time.[8]

According to Jung’s conception of the collective unconscious, the archetypal structures are not fixed, but dynamic. Not only do the archetypes evolve over time, but they also have dynamic and creative activity in the present. Moreover, this activity is not merely a reaction to the activities of consciousness, but is inherent in the unconscious itself. As Jung explains,

If [the unconscious] were merely reactive to the conscious mind, we might aptly call it a psychic mirror world. In that case, the real source of all contents and activities would lie in the conscious mind, and there would be absolutely nothing in the unconscious except the distorted reflections of conscious contents. The creative process would be shut up in the conscious mind, and anything new would be nothing but conscious invention or cleverness. The empirical facts give the lie to this. Every creative man knows that spontaneity is the very essence of creative thought. Because the unconscious is not just a reactive mirror reflection, but an independent, productive activity, its realm of experience is a self-contained world, having its own reality, of which we can only say that it affects us as we affect it–precisely what we say about our experience of the outer world. And just as material objects are the constituent elements of this world, so psychic factors constitute the objects of that other world.[9]

The objective psychic world, or collective unconscious, is thus similar to the objective physical world in that both worlds have objective structures and both worlds have autonomous activity independent of our personal will. For example, just as the objective physical world serves as a creative impetus for the development of our scientific worldviews, the psyche develops and evolves because the objective psyche is not merely repressed conscious contents, but has an autonomous activity that is relatively independent of our personal consciousness. Because this activity of the unconscious is relatively autonomous, it often manifests as a compensation or correction to our conscious views or beliefs. The result is an evolution of the psyche toward wholeness and integration, a process Jung called `individuation’.

In an unconscious compensation, some unconscious content is spontaneously expressed or manifested in consciousness, such as in a dream, and provides the psyche with an opportunity to integrate the unconscious content into consciousness. One of the most interesting and dramatic types of unconscious compensation is the phenomenon Jung calls synchronicity. Synchronicity is necessarily meaningful in the sense that it is a form of unconscious compensation that serves to advance the process of individuation. It is distinguished from other forms of unconscious compensation by the fact that synchronicity involves a connection between inner psychological experience and outer experiences in the world, where the connection is acausal in the sense that the inner experience cannot have been an efficient cause of the outer experience, or vice versa. In short, synchronicity is a meaningful, acausal connection between inner and outer events. Because the phenomenon of synchronicity involves an acausal coordination of the inner and outer worlds in a meaningful way, it is not exclusively a psychological or physical phenomenon, but is “psychoid” meaning that it somehow essentially involves both psyche and matter. Thus, Jung interpreted synchronicity to imply the existence of an extremely profound level of reality prior to any distinction between psyche and matter. In other words, synchronicity phenomena represent a manifestation in consciousness of psychoid structures present in the depths of a transcendental unitary reality Jung called the unus mundus:

Since psyche and matter are contained in one and the same world, and moreover are in continuous contact with one another and ultimately rest on irrepresentable, transcendental factors, it is not only possible but fairly probable, even, that psyche and matter are two different aspects of one and the same thing.[10]

The unus mundus is also implied by the fact that we evidently occupy one reality that contains both psyche and matter, and that these two domains of reality are not absolutely independent and isolated, but interact with each other. As Jung says,

Psyche and matter exist in one and the same world, and each partakes of the other, otherwise any reciprocal action would be impossible. If research could only advance far enough, therefore, we would arrive at an ultimate agreement between physical and psychological concepts.[11]

Jung’s concept of the unus mundus, therefore, not only shows how matter is implicated in the depths of the psyche, but also provides a framework for integrating our understanding of psyche and matter. In this framework, both the objective psychic and objective physical worlds are rooted in a common unity at the depths of reality. Because the unus mundus is normally unconscious, it is experienced as the mysterious Other that is the infinite unseen context of our finite conscious experience. Viewed in its subjective aspect, this unified reality takes the form of a psychic domain containing psychological archetypes that manifest in our inner experience. Viewed in its objective aspect, the unus mundus takes the form of a physical domain containing the archetypal laws of nature that govern manifestations in our outer experience. If psyche and matter are, as this suggests, a single reality viewed from different perspectives, then a comparison of their common elements as revealed in physics and psychology may provide insight into the nature of reality at its deepest and most universal level.

Thomas J. McFarlane


Physics and the Immortality of the Soul


The topic of “life after death” raises disreputable connotations of past-life regression and haunted houses, but there are a large number of people in the world who believe in some form of persistence of the individual soul after life ends. Clearly this is an important question, one of the most important ones we can possibly think of in terms of relevance to human life. If science has something to say about, we should all be interested in hearing.

Adam Frank thinks that science has nothing to say about it. He advocates being “firmly agnostic” on the question. (His coblogger Alva Noëresolutely disagrees.) I have an enormous respect for Adam; he’s a smart guy and a careful thinker. When we disagree it’s with the kind of respectful dialogue that should be a model for disagreeing with non-crazy people. But here he couldn’t be more wrong.

Adam claims that there “simply is no controlled, experimental[ly] verifiable information” regarding life after death. By these standards, there is no controlled, experimentally verifiable information regarding whether the Moon is made of green cheese. Sure, we can take spectra of light reflecting from the Moon, and even send astronauts up there and bring samples back for analysis. But that’s only scratching the surface, as it were. What if the Moon is almost all green cheese, but is covered with a layer of dust a few meters thick? Can you really say that you know this isn’t true? Until you have actually examined every single cubic centimeter of the Moon’s interior, you don’t really have experimentally verifiable information, do you? So maybe agnosticism on the green-cheese issue is warranted. (Come up with all the information we actually do have about the Moon; I promise you I can fit it into the green-cheese hypothesis.)

Obviously this is completely crazy. Our conviction that green cheese makes up a negligible fraction of the Moon’s interior comes not from direct observation, but from the gross incompatibility of that idea with other things we think we know. Given what we do understand about rocks and planets and dairy products and the Solar System, it’s absurd to imagine that the Moon is made of green cheese. We know better.

We also know better for life after death, although people are much more reluctant to admit it. Admittedly, “direct” evidence one way or the other is hard to come by — all we have are a few legends and sketchy claims from unreliable witnesses with near-death experiences, plus a bucketload of wishful thinking. But surely it’s okay to take account of indirect evidence — namely, compatibility of the idea that some form of our individual soul survives death with other things we know about how the world works.

Claims that some form of consciousness persists after our bodies die and decay into their constituent atoms face one huge, insuperable obstacle:the laws of physics underlying everyday life are completely understood, and there’s no way within those laws to allow for the information stored in our brains to persist after we die. If you claim that some form of soul persists beyond death, what particles is that soul made of? What forces are holding it together? How does it interact with ordinary matter?

Everything we know about quantum field theory (QFT) says that there aren’t any sensible answers to these questions. Of course, everything we know about quantum field theory could be wrong. Also, the Moon could be made of green cheese.

Among advocates for life after death, nobody even tries to sit down and do the hard work of explaining how the basic physics of atoms and electrons would have to be altered in order for this to be true. If we tried, the fundamental absurdity of the task would quickly become evident.

Even if you don’t believe that human beings are “simply” collections of atoms evolving and interacting according to rules laid down in the Standard Model of particle physics, most people would grudgingly admit that atoms are part of who we are. If it’s really nothing but atoms and the known forces, there is clearly no way for the soul to survive death. Believing in life after death, to put it mildly, requires physics beyond the Standard Model. Most importantly, we need some way for that “new physics” to interact with the atoms that we do have.

Very roughly speaking, when most people think about an immaterial soul that persists after death, they have in mind some sort of blob of spirit energy that takes up residence near our brain, and drives around our body like a soccer mom driving an SUV. The questions are these: what form does that spirit energy take, and how does it interact with our ordinary atoms? Not only is new physics required, but dramatically new physics. Within QFT, there can’t be a new collection of “spirit particles” and “spirit forces” that interact with our regular atoms, because we would have detected them in existing experiments. Ockham’s razor is not on your side here, since you have to posit a completely new realm of reality obeying very different rules than the ones we know.

But let’s say you do that. How is the spirit energy supposed to interact with us? Here is the equation that tells us how electrons behave in the everyday world:

Don’t worry about the details; it’s the fact that the equation exists that matters, not its particular form. It’s the Dirac equation — the two terms on the left are roughly the velocity of the electron and its inertia — coupled to electromagnetism and gravity, the two terms on the right.

As far as every experiment ever done is concerned, this equation is thecorrect description of how electrons behave at everyday energies. It’s not a complete description; we haven’t included the weak nuclear force, or couplings to hypothetical particles like the Higgs boson. But that’s okay, since those are only important at high energies and/or short distances, very far from the regime of relevance to the human brain.

If you believe in an immaterial soul that interacts with our bodies, you need to believe that this equation is not right, even at everyday energies. There needs to be a new term (at minimum) on the right, representing how the soul interacts with electrons. (If that term doesn’t exist, electrons will just go on their way as if there weren’t any soul at all, and then what’s the point?) So any respectable scientist who took this idea seriously would be asking — what form does that interaction take? Is it local in spacetime? Does the soul respect gauge invariance and Lorentz invariance? Does the soul have a Hamiltonian? Do the interactions preserve unitarity and conservation of information?

Nobody ever asks these questions out loud, possibly because of how silly they sound. Once you start asking them, the choice you are faced with becomes clear: either overthrow everything we think we have learned about modern physics, or distrust the stew of religious accounts/unreliable testimony/wishful thinking that makes people believe in the possibility of life after death. It’s not a difficult decision, as scientific theory-choice goes.

We don’t choose theories in a vacuum. We are allowed — indeed, required — to ask how claims about how the world works fit in with other things we know about how the world works. I’ve been talking here like a particle physicist, but there’s an analogous line of reasoning that would come from evolutionary biology. Presumably amino acids and proteins don’t have souls that persist after death. What about viruses or bacteria? Where upon the chain of evolution from our monocellular ancestors to today did organisms stop being described purely as atoms interacting through gravity and electromagnetism, and develop an immaterial immortal soul?

There’s no reason to be agnostic about ideas that are dramatically incompatible with everything we know about modern science. Once we get over any reluctance to face reality on this issue, we can get down to the much more interesting questions of how human beings and consciousness really work.

Sean Carroll is a physicist and author. He received his Ph.D. from Harvard in 1993, and is now on the faculty at the California Institute of Technology, where his research focuses on fundamental physics and cosmology. Carroll is the author of From Eternity to Here: The Quest for the Ultimate Theory of Time, and Spacetime and Geometry: An Introduction to General Relativity. He has written for Discover, Scientific American, New Scientist, and other publications. His blog Cosmic Variance is hosted byDiscover magazine, and he has been featured on television shows such asThe Colbert Report, National Geographic’s Known Universe, andThrough the Wormhole with Morgan Freeman.

Does time exist?

The most difficult and rigorous of the above 3 questions, the definition of time has perplexed thinkers since ages. Plato argued that time was created when the creator fashioned the world from existing material, giving form to primitive matter. Plato argues in the Timaeus that the creator:

… sought to make the universe eternal, so far as might be. Now the nature of the ideal being was everlasting, but to bestow this attribute in its fullness upon a creature was impossible. Wherefore he resolved to have a moving image of eternity, and when he set in order the heavens, he made this image eternal but moving, according to number, while eternity itself rests upon unity; and this image we call Time.

In the 17th century Galileo discovered a ‘clock’ in the sky which recorded ‘absolute time’, namely the times of the eclipses of Jupiter’s moons. Theoretically this provided a solution to the longitude problem, but in practice observing the eclipses of Jupiter’s moons from the deck of a ship was essentially impossible.

The ultimate version of the mechanical universe appeared in Newton’s Principia in 1687. According to Classical Physics (and Isaac Newton), laws of motion require time to have some specific features. Simultaneity is an absolute concept and time brings an order to the events occurring in space. No matter when or where an event occurs, classical physics assumes that you can objectively say whether it happens before, after or simultaneously with any other event in the universe. In addition, Classical Time must also be continuous to define velocities and accelerations. The whole description of Newton’s laws depended on time and so Newton began by defining time as:

“Absolute, true, and mathematical time, in and of itself and of its own nature, without reference to anything external, flows uniformly and by another name is called duration. Relative, apparent, and common time is any sensible and external measure (precise or imprecise) of duration by means of motion; such a measure – for example, an hour, a day, a month, a year – is commonly used instead of true time.” -Principia

Here we can see the influence of religion, especially deism–the belief that God can exist while allowing natural laws to govern the universe without a supernatural element)–on Newton at the beginning of the Enlightenment.

Now apart from these special features of the absolution in Newtonian time, another concept has to be encompassed by it – the concept of duration, of a metric, so that we can distinguish events apart.

In essence, Newton proposed that the world comes equipped with a master clock. The clock uniquely and objectively carves the world up into instants of time. Newton’s physics listens to the ticking of this clock and no other. Newton additionally felt that time flows and that this flow gives us an arrow telling us which direction is the future.

Newton’s definitions and laws were quickly accepted because they led to correct predictions about the world. Such knowledge also allow us to calculate when such eclipses occurred in the past. Laplace correctly argued that given the laws of mechanics, the complete picture of the past and future world is encapsulated in the present world.

These definitions worked well with the physical observations till the advent of Relativity in the early 20th century. Einstein questioned the absoluteness of simultaneity. According to his special theory of relativity, what events are happening at the same time depends on how fast you are going. The true arena of events is not time or space, but their union: spacetime. Two observers moving at different velocities disagree on when and where an event occurs, but they agree on its spacetime location. In 1909 Minkowski said that:

Henceforth space by itself and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality”. (Minkowski 1909).

Things became worse for Classical time by 1915 with the emergence of General Relativity, which said that gravity distorts time. Only in rare cases is it possible to synchronize clocks and have them stay synchronized, even in principle. This dethroned the Newtonian concepts of space and time. You cannot generally think of the world as unfolding, tick by tick, according to a single time parameter. In extreme situations, the world might not be carvable into instants of time at all.

Now to substantiate upon what time actually is, we can imagine spacetime to be a loaf of bread. Each slice of bread would then form the description of the happenings at a particular instance if the slice the loaf “timewise”. Likewise, we can also slice the loaf “spacewise”. Timelike-related events are those that can be causally related. An object or signal can pass from one event to the other,
influencing what happens. Thus, the following conclusion can be made from General Relativity:

Spacelike related events are causally unrelated. No object or signal can get from one to the other. Observers disagree on the sequence of spacelike events, but they all agree on the order of timelike events. If one observer perceives that an event can cause another, all observers do.

Now let us propose a thought experiment [as proposed by Craig Callender, a philosophy professor at the University of California, San Diego]. Now we know that we can slice the loaf in any way we want.

First we slice the loaf successively with time, bottom up. This creates a series of events like a film in a camera [as shown in the upper portion of the figure]. We can also slice the loaf left to right [as shown in the lower portion of the figure]. Although both the methods of slicing are possible, they are vastly different from each other.

In the normal, past-to-future slicing, the data you need to collect on a slice are fairly easy to obtain. For instance, you measure the velocities of all particles. The velocity of a particle in one location is independent of the velocity of a particle someplace else, making both of them straightforward to measure. But in the second method, the particles’ properties are not independent; they have to be set up in a very specific way, or else a single slice would not suffice to reconstruct all the other slices.
Therefore, this manner of slicing lets us differentiate space from time and vice versa, and lets us define time as:

Time is the direction within spacetime in which good prediction is possible—the direction in which we can tell the most informative stories. The narrative of the universe does not unfold in space. It unfolds in time.


What does the ‘arrow of time’ imply? The (in)existence of Flow of Time:

This part concerns more ontological concepts of time rather than physical ones.
From our day to day experiences we know that time has a direction from “eggs to omelettes” and not vice versa. The arrow of a physical process is the way it normally goes, the way it normally unfolds through time. If a process goes only one-way, we call it an irreversible process; otherwise it is reversible. The amalgamation of the universe’s irreversible processes produces the cosmic arrow of time, the master arrow. Usually this arrow is what is meant when one speaks of time’s arrow. The arrow simply indicates a process unfolding with time, and time need not “flow”. It can be still.
However, the works of Austrian Physicist Ludwig Boltzmann argued that because Newton’s laws work equally well going forward or backward in time, time has no built-in arrow. Instead he proposed that the distinction between past and future is not intrinsic to time but arises from asymmetries in how the matter in the universe is organized.

The above two statements contradict each other, and in fact, physicists are still debating regarding the arrow of time. There are 3 major views regarding the metaphysics of spacetime:

Presentism deals with the present. It says that the present is what exists, and the past is no more existent and the future is not yet. The diagram illustrating presentism also has arrows pointing up (conventionally, towards the future) attached to the plane representing the present. These arrows emphasize the idea that the present (and hence the existent) constantly shifts or changes. These arrows represent, then, the dynamic aspect of time called temporal becoming orpassage.
On the other hand, Eternalism says that ALL the possible events (quantum states) are already present. They are all there and the now like the here is a function of one’s perspective, one’s position in the spacetime, and these positions are indicated by the line in the spacetime representing the history of spacetime locations of a particular object or person. Such a line is often called a world line.
Therefore time has no arrow in case of Eternalist beliefs. Time simply acts as pointers connecting two different events, which we, by our own convention, call the now’s and here’s.
Possiblism offers an intermediate approach. While the future is possible, the past is what is actual and one can notice from the figure itself that the world line is complete till the present. However, the lines can branch into numerous possible futures. This will imply that time can have multiple arrow directions.

Does time exist?

Those who believe that general relativity provides the better starting point begin with a theory in which time is already demoted and hence are more open to the idea of a timeless reality. On the contrary, Physicists who think quantum mechanics provides the firmer foundation, like superstring theorists, start with a full-blooded time.

When physicists rewrote Eintein’s equations for gravity in the same form as the equations for electromagnetism, the idea being that the same techniques used to develop a quantum theory of electromagnetism could then be applied to gravity as well. When physicists John Wheeler and Bryce DeWitt attempted this procedure in the late 1960s, they arrived at a very strange result. The equation (dubbed the Wheeler-DeWitt equation) utterly lacked a time variable. The symbol t denoting time had simply vanished.

Taking the result literally, time doesn’t exist.

Carlo Rovelli and Julian Barbour are the proponents of this timeless theory and are attempting to rewrite quantum mechanics in a timeless manner, just the way relativity requires.

The reason they think this maneuver is possible is that although general relativity lacks a global time, it still manages to describe change. In essence, it does so by relating physical systems directly to one another rather than to some abstract notion of global time. But even if the universe is timeless, somewhere it seems incorrect and incoherent with our observations.

Barbour and Rovelli have each offered suggestions for how time (or at least the illusion of time) could pop out of nothingness. Known as semiclassical time, it goes back to a 1931 paper by English physicist Nevill F. Mott that described the collision between a helium nucleus and a larger atom.

To model the total sysem, Mott applied an equation that lacks time and usually is applied only to static systems. He then divided the system into two subsystems and used the helium nucleus as a “clock” for the atom. Remarkably, the atom, relative to the nuleus, obeys the standard time-dependent equation of quantum mechanics. A function of space plays the role of time. So even though the system as a whole is timeless, the individual pieces are not. Hidden in the timeless equation for the total system is a time for the subsystem.

Therefore, time emerges from timelessness. We perceive time because we are, by our very nature, one of those pieces.


1. Page on Nature
2. Classical time
3. Time According to Sir Issac Newton
4. stanford.eduBeing and Becoming in Modern Physics
5. Page on Utm
6. Consciousness Studies/The Philosophical Problem

P.S. I would highly recommend the episode “Does Time Really Exist” of the documentary series Through the Wormhole [“Through the Wormhole” Does Time Really Exist?

Quantum Logic

Quantum Mechanics as a Probability Calculus

It is uncontroversial (though remarkable) that the formal apparatus of quantum mechanics reduces neatly to a generalization of classical probability in which the role played by a Boolean algebra of events in the latter is taken over by the “quantum logic” of projection operators on a Hilbert space.[1] Moreover, the usual statistical interpretation of quantum mechanics asks us to take this generalized quantum probability theory quite literally—that is, not as merely a formal analogue of its classical counterpart, but as a genuine doctrine of chances. In this section, I survey this quantum probability theory and its supporting quantum logic.[2]

[For further background on Hilbert spaces, see the entry on quantum mechanics. For further background on ordered sets and lattices, see the supplementary document: The Basic Theory of Ordering Relations. Concepts and results explained these supplements will be used freely in what follows.]

Quantum Probability in a Nutshell

The quantum-probabilistic formalism, as developed by von Neumann [1932], assumes that each physical system is associated with a (separable) Hilbert space H, the unit vectors of which correspond to possible physical states of the system. Each “observable” real-valued random quantity is represented by a self-adjoint operator A on H, the spectrum of which is the set of possible values of A. If u is a unit vector in the domain of A, representing a state, then the expected value of the observable represented by A in this state is given by the inner product <Au,u>. The observables represented by two operators A and B are commensurable iff A and B commute, i.e., AB = BA. (For further discussion, see the entry on Quantum Mechanics.)

The “Logic” of Projections

As stressed by von Neumann, the {0,1}-valued observables may be regarded as encoding propositions about—or, to use his phrasing, properties of—the state of the system. It is not difficult to show that a self-adjoint operator P with spectrum contained in the two-point set {0,1} must be a projection; i.e., P2 = P. Such operators are in one-to-one correspondence with the closed subspaces of H. Indeed, if P is a projection, its range is closed, and any closed subspace is the range of a unique projection. If u is any unit vector, then <Pu,u> = ||Pu||2 is the expected value of the corresponding observable in the state represented by u. Since this observable is {0,1}-valued, we can interpret this expected value as the probability that a measurement of the observable will produce the “affirmative” answer 1. In particular, the affirmative answer will have probability 1 if and only if Pu = u; that is, u lies in the range of P. Von Neumann concludes that

… the relation between the properties of a physical system on the one hand, and the projections on the other, makes possible a sort of logical calculus with these. However, in contrast to the concepts of ordinary logic, this system is extended by the concept of “simultaneous decidability” which is characteristic for quantum mechanics [1932, p. 253].

Let’s examine this “logical calculus” of projections. Ordered by set-inclusion, the closed subspaces of H form a complete lattice, in which the meet (greatest lower bound) of a set of subspaces is their intersection, while their join (least upper bound) is the closed span of their union. Since a typical closed subspace has infinitely many complementary closed subspaces, this lattice is not distributive; however, it is orthocomplemented by the mapping

MM = {vH | ∀uM(<v,u> = 0)}.

In view of the above-mentioned one-one correspondence between closed subspaces and projections, we may impose upon the set L(H) the structure of a complete orthocomplemented lattice, definingPQ, where ran(P) ⊆ ran(Q) and P′ = 1 − P (so that ran(P′) = ran(P)). It is straightforward thatPQ just in case PQ = QP = P. More generally, if PQ = QP, then PQ = PQ, the meet of P and Qin L(H); also in this case their join is given by PQ = P+Q − PQ.

1.1 Lemma:
Let P and Q be projection operators on the Hilbert space H. The following are equivalent:

  1. PQ = QP
  2. The sublattice of L(H) generated by P, Q, P′ and Q′ is Boolean
  3. P, Q lie in a common Boolean sub-ortholattice of L(H).

Adhering to the idea that commuting observables—in particular, projections—are simultaneously measurable, we conclude that the members of a Boolean “block” (that is, a Boolean sub-ortholattice) of L(H) are simultaneously testable. This suggests that we can maintain a classical logical interpretation of the meet, join and orthocomplement as applied to commuting projections.

Probability Measures and Gleason’s Theorem

The foregoing discussion motivates the following. Call projections P and Q orthogonal, and writePQ iff PQ′. Note that PQ iff PQ = QP = 0. If P and Q are orthogonal projections, then their join is simply their sum; traditionally, this is denoted PQ. We denote the identity mapping on Hby 1.

1.2 Definition:
A (countably additive) probability measure on L(H) is a mapping μ : L → [0,1] such that μ(1) = 1 and, for any sequence of pair-wise orthogonal projections Pi, i = 1,2,…

μ(⊕i Pi) = ∑i μ(Pi)

Here is one way in which we can manufacture a probability measure on L(H). Let u be a unit vector of H, and set μu(P) = <Pu,u>. This gives the usual quantum-mechanical recipe for the probability that P will have value 1 in the state u. Note that we can also express μu as μu(P) = Tr(P Pu), wherePu is the one-dimensional projection associated with the unit vector u.

More generally, if μi, i=1,2,…, are probability measures on L(H), then so is any “mixture”, or convex combination μ = Σi tiμi where 0≤ti≤1 and Σi ti = 1. Given any sequence u1, u2,…, of unit vectors, let μi = μui and let Pi = Pui. Forming the operator

W = t1P1 + t2P2 + … ,

one sees that

μ(P) = t1Tr(P P1) + t2Tr(P P2) + … = Tr(WP)

An operator expressible in this way as a convex combination of one-dimensional projections in is called a density operator. Thus, every density operator W gives rise to a countably additive probability measure on L(H). The following striking converse, due to A. Gleason [1957], shows that the theory of probability measures on L(H) is co-extensive with the theory of (mixed) quantum mechanical states on H:

1.3 Gleason’s Theorem:
Let H have dimension > 2. Then every countably additive probability measure on L(H) has the form μ(P) = Tr(WP), for a density operator W on H.

An important consequence of Gleason’s Theorem is that L(H) does not admit any probability measures having only the values 0 and 1. To see this, note that for any density operator W, the mapping u → <Wu,u> is continuous on the unit sphere of H. But since the latter is connected, no continuous function on it can take only the two values 0 and 1. This result is often taken to rule out the possibility of ‘hidden variables’—an issue taken up in more detail in section 6.

The Reconstruction of QM

From the single premise that the “experimental propositions” associated with a physical system are encoded by projections in the way indicated above, one can reconstruct the rest of the formal apparatus of quantum mechanics. The first step, of course, is Gleason’s theorem, which tells us that probability measures on L(H) correspond to density operators. There remains to recover, e.g., the representation of “observables” by self-adjoint operators, and the dynamics (unitary evolution). The former can be recovered with the help of the Spectral theorem and the latter with the aid of a deep theorem of E. Wigner on the projective representation of groups. See also R. Wright [1980]. A detailed outline of this reconstruction (which involves some distinctly non-trivial mathematics) can be found in the book of Varadarajan [1985]. The point to bear in mind is that, once the quantum-logical skeleton L(H) is in place, the remaining statistical and dynamical apparatus of quantum mechanics is essentially fixed. In this sense, then, quantum mechanics—or, at any rate, its mathematical framework—reduces to quantum logic and its attendant probability theory.

Interpretations of Quantum Logic

The reduction of QM to probability theory based on L(H) is mathematically compelling, but what does it tell us about QM—or, assuming QM to be a correct and complete physical theory, about the world? How, in other words, are we to interpret the quantum logic L(H)? The answer will turn on how we unpack the phrase, freely used above,

(*) The value of the observable A lies in the range B.

One possible reading of (*) is operational: “measurement of the observable A would yield (or will yield, or has yielded) a value in the set B”. On this view, projections represent statements about the possible results of measurements. This sits badly with realists of a certain stripe, who, shunning reference to ‘measurement’, prefer to understand (*) as a property ascription: “the system has a certain categorical property, which corresponds to the observable A having, independently of any measurement, a value in the set B”. (One must be careful in how one understands this last phrase, however: construed incautiously, it seems to posit a hidden-variables interpretation of quantum mechanics of just the sort ruled out by Gleason’s Theorem. I will have more to say about this below.)