Philosophical Correlates to Hemisphere Functionc. 2011 by John LaMuth (4,000 words)
The grand correlation of the reflective mind to the structure of the human brain is an anticipated achievement whose time has finally come. Countless lifetimes of research have been spent in the fields of behavioral psychology and philosophy in preparation for the day when the gap separating these two great disciplines would finally be bridged. The introspective discipline of philosophy has traditionally maintained a substantial lead in the search for a mind/brain synthesis. The philosophical concept of reflective awareness goes clear back to antiquity. On the other hand, neuroanatomical research into the structure of the human brain dates only to the last few centuries, with the bulk of the research gathered over only the last 50 years. Up until a decade or so ago, not enough was known about the total activity of the brain to even guess as to the basis for general human reflection, much less its particular details. The bilateral symmetry of the paired cerebral hemispheres was originally suggestive of this type of reflective interaction, although experimental verification was long in coming. In this regard, virtually every neocortical area is connected with its mirror image area in the opposite hemisphere by way of the large bundle of nerve fibers known as the corpus callosum. Only a few minor exceptions, such as primary visual area #17, as well as the sensory representations for the hands and feet, circumvent this symmetrical pattern of bilateral connection. This missing contribution is insignificant compared to the estimated 200 million total nerve fibers within this commissure bundle. This dual-directional conductivity for the corpus put callosum, accordingly, is rated in the billions of nerve impulses per second. The magnitude of this interhemispheric information system rivals even the intra-cortical pattern of connectivity that connects the various areas within a single hemisphere. Although both hemispheres are virtually indistinguishable on a gross anatomical level, a general asymmetry in function has recently become apparent over the last few decades. For almost a century it has been known that the cortical speech areas are virtually always located within the left hemisphere, also designated as the dominant hemisphere. Any asymmetry of hemisphere function in normal subjects is obscured by the massive bundle of fibers connecting corresponding points within each hemisphere.
The therapeutic series of surgical sections of the corpus callosum in epileptic patients gave the first major indications of this significance of this bundle of fibers in a global psychological phenomenon of reflection. The unobstructed accessibility to the corpus callosum via the dorsal cleft between the two hemispheres permits a selective disruption of this tract without damage to adjoining cerebral structures. This surgical procedure was undertaken and that is the course of last resort for over a dozen epileptic patients suffering from chronic seizures intractable to even heavy medication. Unilateral seizures were effectively blocked from passing to the opposite hemisphere, wherein promoting a marked remission of the debilitating aspects of the epileptic syndrome.
The postoperative psychological testing of a number of these patients by Sperry (and associates) has clearly indicated the potential for a fully independent hemisphere function. Each hemisphere in the split-brain patient receives its own spatially exclusive complement of sensory input the determined by the bilateral localization of spinal and brainstem tracts ascending to the forebrain. These bilateral input restrictions imposed upon each cerebral hemisphere serves as the basis for the classic experimental designed by Sperry for testing the reactions of the functionally isolated hemisphere. For instance, the finer discriminative aspects of the tactile sense relayed by way of the dorsal column tract project to the hemisphere situated across from the side of the body that had been stimulated. This sensory specificity is exploited in the experimental situation by placing a familiar object into either the left or right hand of the patient out of the line of vision and soliciting a subjective impression. The visual modality exhibits a similar bilateral specificity in that the portions of the retina directed towards the left hand of the visual field project to the right hemisphere, while the opposite proves true for the right half of the visual field. Here, the experimental design is modified so that a picture or written information is flashed to either the left or right visual field for a scant one-tenth of the second, so as to defeat in the subsequent shifts in the gaze of the subject that would tip off the contralateral hemisphere.
The catalogued subjective reports of the test subjects in the various experimental contexts have yielded a quite unexpected interpretation of the functional variability between the two cerebral hemispheres. Sperry was able to show that the two hemispheres communicated in radically different styles, prompting the functional distinctions of the dominant hemisphere and the minor hemisphere. The dominant hemisphere alone communicates through verbal language consistent with the corresponding location of the major speech centers within this hemisphere. Sperry estimates that the left hemisphere exhibits this dominance aspect in roughly 98 percent of the cases studied, making these two aspects virtually synonymous for all intents and purposes. Likewise, the right hemisphere is invariably associated with an expressive mode that is attributed to more of a minor role. The minor hemisphere communicates only in a nonverbal, gestural style that further brings to mind its descriptive designation as the “mute” hemisphere. The verbal communication of the dominant hemisphere, and the gestural expression of the minor hemisphere, were paradoxically shown to independently occur, often completely at odds with one another. In a classic series of controlled psychological studies on split-brain patients, Sperry (et. al., 19xx) demonstrated that the dominant hemisphere operates in an essentially independent fashion from the minor hemisphere. For instance, the patient was seated so that words flashed on a screen were visible only to the left or right hemisphere. The word “pencil” was projected so as to reach only the right minor hemisphere. On questioning after the presentation, the patient replied that no word had been seen, which is consistent with the location of the speech areas in only the left hemisphere. However, simultaneous to the verbal denial, the left hand (which is controlled entirely by the right hemisphere) proceeded to a tray of small objects out of the line of vision, and through tactile discrimination was consistently able to selected named object. The minor hemisphere demonstrated the capability for an intelligent course of action, yet it was unable to express itself verbally; hence, the designation of mute hemisphere. The dollar hemisphere was capable of reporting in the first person tense, The noting the functioning of the “I” ego. If the transcendent ego is posited only in the dominant hemisphere, what is the nature of the mute intelligence located in the minor hemisphere? By all right appearance, the right hemisphere appears impersonal in its mode of expression, which seems somewhat reminiscent of Sartre’s prepersonal aspects of consciousness. Perhaps transcendence of consciousness is posited in the minor atmosphere, just as the transcendent ego is specialized to the dominant hemisphere.
Sartre expresses a similar portion of view in the following quotation: “It will be said that a principle of unity with duration is, nevertheless, needed is the continued flux of conscious is capable of positing transcendent objects outside the flux. Consciousness must be a perpetual synthesis of past consciousnesses and present consciousness, thus consciousness refers perpetually to itself. The whole of consciousness is a singular property that belongs to consciousness itself aside from any relations if they have with the “I.” Consciousness can be limited only by itself. … Thus it constitutes a synthetic and individual totality entirely isolated from other totalities of the same type, and the “I” can evidently only be an expression (rather than a condition) of this incommunicability and inwardness of consciousness.” The impersonal mode of expression for the minor hemisphere is exceedingly reminiscent of the non-positional property of consciousness. Sartre defines as property in the following quotation: “The essence of consciousness is an absolute, because consciousness is consciousness of itself. Consciousness is not positional, or is not for itself its own object. Its object is by nature outside of it, which is why it posits and grasps the object in the same act. Unreflected consciousness of the first-degree knows itself only as absolute inwardness.” The accurate tactile discrimination of the minor hemisphere demonstrates a clear correspondence to Sartre's concept of translucence, which is more fully described in the following quotation: “Pure consciousness is an absolute quite simply because it is consciousness of itself. It remains, therefore, a phenomenon in the very special sense of which “to be” and “to appear” are one (translucence). Consciousness with out the “I” is absolutely existent by virtue of “now” existence.”
This definition of the minor hemisphere in terms of now existence is certainly in agreement with the experimental evidence. Despite the good performance of the right hemisphere with respect to the names of common objects, even the simplest of verbs, or verbal commands, are not comprehended by it. In addition, Sartre also writes: “… transcendental consciousness is an impersonal spontaneity. It determines its existence at each instant, without our being able to conceive anything before it. Thus, each instant of our conscious life reveals to us a creation “ex nihilo.” Not a new arrangement, but a new existence. There is something distressing for each of us to catch in the act this tireless creation of existence of which we are not the creators. At this level man has the impression of ceaselessly escaping from himself, of overflowing himself, of being surprised by riches which are always unexpected.
The dominant hemisphere is by all outward appearance the structural substrate of the transcendent ego. The dominant hemisphere is freely expressive in terms of verbal communication, suggesting a functional orientation primarily temporal dimension. The sequential ordering of word concepts into syntactical statements that define past or future events seemingly verifies such a time-ordered capability of the ego. Sartre similar writes in the following quotation: “… the ego is not the real totality of consciousness (such a totality would be a contradiction, like any infinite unity enacted), but the ideal unity of all the states and actions? Be ideal, naturally, this unity can embrace an infinity of states. By virtue of this concrete nucleus, a more or less sizeable quantity of empty intentions (by right, an infinity of them) are directed towards the past and toward the future, and aim at the states and actions not presently given.” The “I” ego, as the unity of actions, is necessarily optimized for abstraction within a temporal dimension for directing actual responses of a complex task. Sartre suggests a similar point in the following quotation: “We must not forget that action requires time to be accomplished. It has articulations; it has moments. To these moments correspond concrete, active consciousnesses, and the reflection which is directed on the consciousnesses apprehends the total action in intuition, which exhibits it as the transcendent unity of the active consciousnesses.” The dominant hemisphere is incompetent on virtually any variety of spatial task, suggesting that that time-oriented dominant hemisphere is complemented by the spatially-oriented minor hemisphere, and vice versa.
From this exhaustive type of analysis, it would appear that the distinctive functional characteristics of the human cerebral hemispheres exhibit a precise correspondence to the existential notions of the “I” ego and consciousness. The results of the split-brain studies indicate that the two hemispheres interact in an information capacity during reflection, suggesting a similar relationship applies for the subjective constructs of consciousness and the ego. Certain psychological deficits were, nevertheless, aparent in split brain patients due to the section of the corpus callosum, suggesting that information interchange between hemispheres is crucial in this sphere of reflective consciousness. A description of the most familiar form of reflection (Cartesian reflection) serves to illustrate in greater detail how the ego and consciousness interact during reflection in general. According to the classical Cartesian formula: “I think, therefore I am” represents a prime example of reflection concerning the ego. Edmund Husserl, in Cartesian Meditations, further demonstrates the dual character for this formula: the components of which are, I think of a proposition (P), and I am aware I think (P). Sartre, in contrast denies the existence of this transcendental “I” in awareness. Hear the statements are revised to reflect: I think (P), and am aware I think (P). From a historical perspective, it is significant to note that prior to Husserl’s influence, the phenomenon of intentionality was only considered to be a simple two-term relationship. Intentionality was first considered as a philosophical issue by the medieval school of Scholasticism. The scholastics were founded upon the authority of the Latin fathers, as well as Aristotle and his commentators. According to the scholastics, intentionality was defined precisely as the particular aspect of consciousness to be conscious of an object. It follows that mental events such as imagining, thinking, etc., share the common aspect of being directed to an intentional object in a matter distinct from the other types of physical causality. Medieval scholastics further characterized intentional acts as mental references to a content, a mental direction of upon the object. The original version of intentionality, termed representationalism, proposes that physical objects set up a corresponding mental representation or content within the mind that is intentionally grasped by the subject. This representational model, however, proves inadequate for explaining the occurrence of mental acts of imagination directed toward nonexistent objects, such as the unicorn.
The concept of intentionality was first introduced to contemporary philosophy in 1874 by the German philosopher/psychologist, Franz Brentano. Brentano's background in scholasticism served as the foundation for the transition to his own distinctive brand of descriptive psychology. Brentano tried to circumvent the inconsistencies in the classical formulation of intentionality by revising a few key points. Although he progressed through a number of different formulations, Brentano envisioned intentionality as a relation between a subject an entity that may or may not exist. Difficulties emerged, however, when attempting to categorize the existential status of this entity with regard to fantasy or reality.
It was only through the radical insights of Brentano’s under study, Edmond Husserl, that resolved the inconsistencies plaguing intentionality theory. Although trained as a mathematician, Husserl defected to philosophy under the influence of Brentano’s lucid brand of descriptive scientific philosophy. Husserl went on to establish his own philosophical movement with the publication in 1906 of Ideas; General Introduction to Pure Phenomenology. In the seminal work, Husserl was the first to propose that intentionality was actually a three-term style of relationship. According to Husserl, each act is associated with a noema: a mental content through which the act is directed towards its object. The act of imagining a unicorn has a specific noema, even though it is directed towards an unreal object. The noema manifests itself as a psychic intermediary, uniting the actively intending ego with its intentional object. The transcendent and transcendental aspects of Husserl’s notion of the ego showed distinct functional parallels to the ego/consciousness dualism previously described by Sartre. Husserl distinguishes this type of functional dualism concerning the ego in terms of the corresponding designations of the noema and noesis. According to Husserl, the noema corresponds to the unitary aspect of the ego-experience, whereas noesis relates to the constituting variety factors. Husserl develops this stain more thoroughly near the end of section 15: “If we follow this methodological principal in the case of the dual topic, their became opened to us, first of all, the general descriptions to be made, always on the basis of a particular cogitationes, with regard to each other to correlative sides. Accordingly, on the one hand, descriptions of the intentional object as such, with regard to the determinations attributed to it in the modes of consciousness concerned, attributed furthermore with corresponding modalities, which stand out when attention is directed to them. For example: the modalities of being, like certainly being, possibly or presumably being, etc.; or the subjective-temporal modes, being present, past, or future. This line of description is called noematic. Its counterpart is noetic description, which concerns the modes of the cogito itself, the modes of consciousness (for example: perception, recollection, retention), with the modal differences inherent in them (for example: differences in clarity and distinctness).”
The functional distinctions already shown to exist between the two cerebral hemispheres clearly parallel the differences between noesis and noema. Both noesis and noema will further be examined in the context of phenomenological reduction for clues to the innermost workings of this alternate form of reflection. The general type reflectionant’s principle differs radically from the reciprocal (intentional) reflection just described. Husserl clearly distinguishes these two types of reflection in section 80 of Ideas. He states that in general acts of reflection, I apprehend myself to be present as the human being that I am. This human I-ego corresponds to the “I think” of the Kantian tradition. Such reflections by consciousness are clearly distinguished from phenomenological reduction by Husserl. Phenomenological reduction is the reflective technique which served as the basis for all of Husserl’s radical insights into the field of Phenomenology. Husserl’s phenomenological reduction is composed of two distinct stages similar to the thinking and knowing phases of Kantian reflection. The neuroanatomical basis for each stage of reduction reciprocally parallels the neural events previously cited as underlying general reflection.
The first-stage of phenomenological reduction is designated transcendental reduction, or phenomenological epoche, also known as bracketing. Epoche is defined as the observation of an object as experienced in the present, disavowing any judgment concerning its enduring existence. This process is antithetical to the basis for the natural sciences, which draw fresh inferences by means of general reflection ordered in accordance with the logic of experience. The scientific method demands a naive acceptance of experiences of a transcendent nature as the subject for theoretical inquiry. The epoche phase, however, sets the thesis of the natural standpoint completely out of action, setting aside all inferences concerning the laws of nature. Instead of living in and inquiring from, the perspective of the continuum of nature, such cognitive theses are tied up or bracketed from a phenomenological standpoint. It represents an observation of the object has actually experienced in the present, disallowing any reference to its enduring existent. With the time dimension attenuated, the transcendental consciousness of the right hemisphere is free to develope a holistic unification of gestalt characteristics entirely within the here and now. This process is technically defined as bracketing the transcendent object and retracting the attention to the transcendental noema. Accordingly, the pictorial and pattern sense of the right hemisphere is accented, while the temporal qualities of the left hemisphere are bracketed.
After suspending the reality of the world, the phenomenological residuum that remains is the sphere of pure consciousness in its absolute being. Husserl states that consciousness in itself has a being of its own, which in absolute uniqueness remains unaffected by the phenomenological disconnection. Epoche gives pure consciousness (and the whole phenomenological region) its objective accessibility. Within the residuum of the phenomenological suspension they're necessarily remains the pure ego displaying a non-constituted transcendence (or transcendence in immanence). This pure ego is fundamentally different from the empirical human ego, being differentiated in each stream of experience as the following cogito. Husserl takes a similar position at the end of section 8 in Cartesian meditations (find that quote).
The bracketing phase of phenomenological reduction further invalidates the extensions of the time dimension related to the past and future states of being. Husserl suggests that phenomenologically purified consciousness forfeits not only its attachment to the material world, but also with setting in cosmic time. The chronological notions of precession and succession, even sequentiality, remain forever external to the state of suspended judgment. With the time representation of the dominant cerebral hemisphere attenuated, the transcendental consciousness of the minor hemisphere is free to develop a holistic pattern of experience entirely within the here and now. This phasing out of activity within the the dominant hemisphere during epoche must be evident on the higher levels of consciousness, as it was in the case of a recall on the primary level.
The second stage of phenomenological reduction is termed eidetic reduction by Husserl (eidos = essence). Eidetic reduction takes the residuum remaining from the bracketing epoche and translates it into the universal essence of experience. The essential universality of the most through which our perceptions are inwardly lived are eidetically actualized according to their essential possibilities within the realm of variation. As the core lead of our factual experience, the real world presents itself as a special case of the variety of possible worlds that are eidetically imaginable to the empirical ego.
Using a useful analogy, eidetic reduction is methodologically comparable to a geometry of experience. From a given number of axioms, Euclidean geometry derives along strictly logical lines the totality of all possible formulations with it its theoretical domain so that nothing in principle remains open within it. In relation to the essential nature of space, geometry is methodologically capable of foreseeing the construction of all possible forms within its domain without being limited to determining each and every one of them. Eidetic reduction operates on the same essential lines except that modes of consciousness are in focus rather than spatial constructs. Husserl states that it is only the individual element that Phenomenology ignores, while a raises into eidetic consciousness the whole of the domain of essences in their concrete fullness.
The method for performing eidetic reduction involves shifting to the abstract experience of the universal and essential properties of the bracketed consciousness. One has only to think of different perceptual versions of say a chair, while intuitionally varying the properties in order to discern the qualities essential to the essence of the chair. The essence of the chair, which is the property of a real-life object, is distinct from the meaning of chair determined out of the sensory context. Here the meaning of a tree (which represents an abstract concept from experience) is not necessarily equivalent to the essence of the tree (which represents a property of the object in the real world). The perceptual vector termed the tree is borne through the definition as to the best set of sensory rules concerning what to include in this concept. It is possible to gain intuition in to the essential nature and relationship of mental phenomena through the overall analysis of experience as systematically varied in eidetic imagination. In this sense, one maintains in the imagination a multitude of variations of the experience, and focuses one's attention upon that which remains unchanged in the multiplicity. This essence this essentially invariant, for it is primarily what is maintained in continuous evidence during the process of variation. The result of eidetic reduction is the true essence of the original object in its purest form.
In conclusion, the reflective process of phenomenological reduction exhibits distinct parallels to the previously described Cartesian style of reflection. The epoche and eidetic stages of phenomenological reduction appear to correspond to the thinking and knowing phases of Cartesian reflection, with the exception that their order occurs within a different cerebral hemispheres. A parallel description of differing semantic fields within the two hemispheres would seem to corroborate exactly such a speculation. As was the case for Cartesian reflection, this superficial type of philosophical correlation to hemisphere function is not entirely convincing without a more detailed range of correspondence. It is further possible to demonstrate the three level hierarchy of functional interaction for phenomenological reduction, just as a reflective ego was described in terms of the qualities, states, and ego. In this manner, phenomenological reduction exhibits the same reliable correlation to brain structure that was already shown for Cartesian reflection. Therefore, phenomenological reduction formally appears to mirror the ego-driven dynamics of Cartesian reflection in relation to the mirror-image symmetry linking the paired cerebral hemispheres.
In conclusion, through the breakthrough prerequisites of the dual parameter grid, a suitably effective correlation between the principles of behavioral psychology and human forebrain organization finally becomes conceptually complete. This innovation was technically proposed in terms of a common exteroceptive, interoceptive, and proprioceptive organizational dynamic for both brain and behavior. This functional correlation to behavioral principles, however, only technically applies to the organizational dynamics restricted to a single cerebral hemisphere, necessitating a further degree of functional analysis targeting the interactivity linking the paired cerebral hemispheres for ultimately explaining the linguistic and ethical aspects specified within the three-digit coding system. Through the aid of the parallel reflective concepts of Cartesian reflection and phenomenological reduction, a thoroughly adequate model of the linguistic aspects of the ethical hierarchy is finally proposed, extending its underlying behavioral foundations to a parallel correlation within the realm of the pure neurosciences. Although this cursory sphere of speculation admittedly represents the briefest of outlines for such a grand unified endeavor, the full details are ultimately reserved for an upcoming book release.