Talk:Multiple thought streams

Multiple parallel modalities

"In an ambitious new theory of the processes of consciousness, Dennett (1992) challenges the standard view of consciousness. This he characterizes as the "Cartesian Theatre" view in which the subjective self i likened to a privileged observer watching a play in which everything comes together on the stage. In other words, consciousness is akin to watching a single sequence of perceived events unfolding before us which match the actual sequence of real events occurring outside of us. Against this view, Dennett argues for what he calls a "multiple drafts model" in which "all varieties of perception -- indeed, all varieties of thought or mental activity -- are accomplished in the brain by parallel, multi-track processes of interpretation and elaboration of sensory inputs" (o. 111). In other words, the contents of consciousness, far from being a unified stream, consist of multiple narratives which are undergoing continuous editorial revision. The significance of these ideas in this context is that they imply a multivocal quality identical to that attributed by social constructionist writers to interpersonal and societal symbolic transactions."^[1]

Building Blocks vs Unified Fields

"Following Searle (2000), we can distinguish two models of the structure of consciousness: the building block model and the unified field model.3 The building block theorist takes the subject's overall phenomenal perspective—the stream of experience—to be built up out of units of consciousness—phenomenal ‘building blocks’. A building block theorist could follow O'Brien and Opie in holding that a conscious individual has “several distinct phenomenal consciousnesses, at least one for each of the senses, running in parallel” (O'Brien & Opie 1998: 387), or they could argue for a different account of how thick the building blocks of consciousness are. What they will agree on is that, at any one time, a conscious individual does not enjoy a single consciousness‐generating system.

The unified field theorist denies that the subject's phenomenal perspective is built up out of individual phenomenal units. Instead, she holds that each of the phenomenal features that contribute to the subject's phenomenal perspective is conscious in virtue of the fact that it is caught up in the subject's phenomenal field. The unified field theorist recognizes that there is multiplicity within the contents of consciousness at any one point in time, but she denies that this multiplicity is a manifestation of the activity of multiple consciousness generating systems.

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Nancy Kanwisher comes closer to an explicit endorsement of the building block model:

'The multiplicity of cortical loci where correlations with awareness have been found provides some evidence against one of the oldest ideas about consciousness, that the contents of awareness are represented in a single unitary system. … Instead, the data described above seem more consistent with a view in which the contents of current awareness can be represented in many different neural structures. However, one could still argue that the neural correlates described above are not in fact the actual representations that constitute the conscious percept, but merely information that is likely to make it onto the (as‐yet‐undiscovered) screen of awareness, so the possibility of such a unitary awareness system is not definitively ruled out by these data. In contrast to the idea of a unitary and content‐general Cartesian theatre of awareness, the data summarized above fit more naturally with the following simple hypothesis: the neural correlates of awareness of a particular visual attribute are found in the very neural structure that perceptually analyzes that attribute. (Kanwisher 2001: 97, emphasis in original).'

Perhaps the most explicit endorsement of the building block model, at least within the cognitive neurosciences, comes from Zeki and collaborators.

'Activity at each stage or node of a processing–perceptual system has a conscious correlate. Binding cellular activity at different nodes is therefore not a process preceding or even facilitating conscious experience, but rather bringing different conscious experiences together. (Bartels & Zeki 1998: 2330; see also Zeki 2007).'

Zeki and Bartels call these conscious experiences ‘micro‐consciousnesses’, and appear to conceive of them as phenomenal building blocks.

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Arguably, the best case to be made for phenomenal disunity in human beings concerns epileptic patients who have undergone section of the corpus callosum—so‐called split‐brain patients. Under carefully controlled laboratory conditions, split‐brain patients sometimes behave as though they have two streams of consciousness, one in each hemisphere (see e.g. Marks 1981; Zaidel et al. 2003). For example, the split‐brain patient might be shown the word ‘key‐ring’, so that ‘key’ falls within the patient's left visual field and ‘ring’ falls within the patient's right visual field. The contralateral structure of the visual system ensures that stimuli projected to the left visual field are processed in the right hemisphere and vice‐versa. When asked to report what she sees the patient in the key‐ring experiment will typically say only that she sees the word ‘ring’, yet, with her left hand the patient may select a picture of a key and ignore pictures of both a ring and a key‐ring. According to the two‐streams model of the split‐brain syndrome, this disunified behaviour is a manifestation of the fact that the split‐brain patient has two streams of consciousness, one in each of her two hemispheres.

Although it is the received view of the split‐brain, there is good reason to regard the two‐streams account with some suspicion. For one thing, split‐brain patients enjoy behavioural unity outside of carefully controlled laboratory settings; in everyday life, they behave as would someone with a single phenomenal perspective (Zaidel 1994).6 Furthermore, it is possible to explain the disunified behaviour of the split‐brain patient without supposing that she or he has a disunified consciousness. In order to do this, we need only suppose that the patient has a single phenomenal field whose contents “switch” between the two hemispheres in accordance with shifts in hemispheric activation (Levy 1977; 1990; Levy & Trevarthen 1976). According to this ‘switch’ model, the split‐brain operation does not split the patient's stream of consciousness into two, but merely limits the degree to which the patient's phenomenal field can simultaneously draw on the neural activity of both hemispheres. In effect, the model represents the split‐brain patient as operating with only half of a phenomenal mind at a time. The everyday consequences of this deficit are minimal because activation moves back and forth between hemispheres as and when it is needed.

In my view the switch model provides the best overall account of the split‐brain. However, the model is controversial, and it may well be the case that some split‐brain patients do, on occasions, have two streams of consciousness. Would this provide support for the building block model? I think not. The streams of consciousness that, according to the two‐streams model, split‐brain patients enjoy hardly look like phenomenal building blocks. There is some elasticity within the building block approach as to how ‘big’ the building blocks of consciousness are, but it is implausible to suppose that the typical phenomenal field is composed of only two building blocks, one grounded in each hemisphere. So even on the two‐streams account of the split‐brain we should not think of the split‐brain syndrome as revealing the pre‐existing structure of consciousness."^[2]

Interacting cognitive subsystem model

"Interacting Cognitive Subsytems (ICS) is a comprehensive systemic model of the organization and function of the resources underlying human cognition. in this paper we use ICS to provide a conceptual framework for understanding normal and dysfunctional cognitive-affective relationships, and their modification.

ICS proposes nine interacting cognitive subsystems, each specialized for handling a specific type of information. We describe the operations of ICS and its account of emotion development and production. ICS emphasizes the importance, as part of the total cognitive configuration producing emotion, of a schematic synthetic level of processing that integrates both propositional meaning and direct sensory contributions. Processing at this level corresponds, subjectively, to holistic “sense” or “feeling” rather than to thoughts or images. We illustrate this emphasis by comparison of ICS with the model underlying cognitive therapy."^[3]

Dipsychism and Polypsychism

"The theories of mental organization that emerged can be concisely classified into two main groups: the theory of dipsychism and that of polypsychism [3], implying either two "layers" of consciousness or more than two.

If there were two layers (dipsychism) the first was conceived as the normal waking consciousness, the second as usually hidden, but occasionally revealing itself in dreams, abnormal symptoms, in hypnosis, and occasionally in unusual and unexpected creative acts. The two layers of personality (or consciousness) were assigned different qualities, depending on the authorities describing them. In what Ellenberger calls the "closed" form of the theory the subconscious contains only tendencies and memories arising in the experience of the individual, but no longer available to the waking consciousness. According to Janet, who was the first to use the expression "subconscious," the unavailable ideas, as we have already noted, became "dissociated" or "disaggregated," so that they could not be synthesized into waking awareness; Freud, in his first concept of the unconscious believed that it consisted of "repressed" thoughts or wishes. Hence dissociation and repression described essentially the same facts of a closed subconscious layer. In the "open" form of the theory, the subconscious layer is not only more extensive than the conscious layer, but it has access to some broader sets of experience that may never have been in the waking consciousness. Such a "subliminal self was posited by Myers [4, 5] and was favorably supported by James in his Varieties of Religious Experience [6]. This general position has found more recent expression in Jung's collective unconscious and in his belief in universal archetypes and mandala symbols in dreams [7]. The issue is again of interest because of present-day romanticism about consciousness expansion and human potentiality. The iceberg analogy is often used, with consciousness merely the portion that is visible and the larger (and more important) portion beneath the surface.

Another distinction differentiates various views of the subconscious in the "closed" and "open" form. In one position, common to Janet and the early Freud, the subconscious (or unconscious) portion is somewhat debased as being fragmented, illogical, or impulse ridden (as in the seething cauldron picture of the unconscious associated with early psychoanalysis). The opposite view is that the subconscious (whether "closed" or "open") may be the source ofmorality, inspiration, or creativity. Oddly enough, the phenomenal observations are as contradictory as the theories explaining them.

The polypsychic theories accept the general notion of splits in the personality or ego but assert that the cleavages may result in more than two subordinate parts. Freud, for example, moved from his earlier dipsychism1 to a tripsychism in proposing the division into id, ego, and superego: "The poor ego has a still harder time of it; it has to serve three harsh masters, and has to do its best to reconcile the claims and demands of all three. ... The three tyrants are the external world, the superego and the id" [8, p. 108]. His later disciples have divided the ego into numerous apparatuses and substructures [9, 10]."^[4]

Some criticisms of multi-phenomenological conscious states

Multiple Realizability Revisited: Linking Cognitive and Neural States

No double-dissociation between optic ataxia and visual agnosia: Multiple sub-streams for multiple visuo-manual integrations

Train of Thought Neurobiology

Cooperation between the default mode network and the frontal–parietal network in the production of an internal train of thought

References