I don't think the mind itself is 'stratified', unless you're referring to traditional concepts of the hierarchical relationship between consciousness and the 'subconscious' (including the personal biographical subconscious, the deeply, bodily, unconscious, and the collective 'unconscious' which would better be referred to, I think, as the collective subconscious). The "subconscious mind" is now becoming a viable concept in several lines of brain/mind research as a result of recognitions of the degree to which we often operate on the basis of the 'automatic pilot' it provides.
Moreover, when we come to recognize the sources of 'meaning' expressed by our species (beginning in artistic expression and expanding in other forms and directions of expressiveness) we are confronted with works of the 'mind' that involve both prereflective consciousness and reflective consciousness. It seems to be the case, as parapsychologists and psychical researchers have long recognized, that the mind works with and through subconscious ideation and subconsciously received information as well as active waking consciousness. In other words, there are subconscious inflows into the conscious mind through permeable 'boundaries'. Rather than adopting the iceberg metaphor to denote the conscious mind's distinction (separation) at the water line from the 90 percent of human protomentality situated beneath and beyond conscious thought/mentation, it might be more valid to think of the conscious mind and the subconscious mind as interrelated in a more fluid environment {say, for example, an underground spring issuing into a body of water, in which what is sensed and inchoately 'known' in the underground water remains intermingled with what becomes visible and otherwise sensible and thinkable in the pool of water that forms at the surface (which is continually charged by what continues to flow upward from the spring's source deep in the earth in cases where the spring issues not just in a local body of water but one which flows into a river eventually issuing in a sea).
It's just a metaphor but it might be an accurate one to represent the holism of consciousness realized at and through various levels of existence in its issuing and evolution from its ultimate grounding conditions in physical nature. To carry the metaphor a little further, the water issuing from deep underground springs -- such as the one located 20 miles from where I live, claimed to be the deepest underground spring on the planet, is extraordinarily clear by the time it pools at the surface and begins its subsequent issuance in a river that empties into the Gulf of Mexico -- incredibly clear except after considerable storms in the area during which tannin from tree roots on and beneath the banks of the pool leaks into the water and stains it the color of strong tea. I think we are intrinsically 'one' with the natural world in which, from which, we have evolved, despite the development of consciousness and mind by which we are able to stand a degree or two apart from 'what-is' and express the 'difference' brought about by our perspective -- which is always colored by the natural (and later the cultural) world in which we exist.
Is the mind stratified? I've been thinking about this in terms of the popular "Triune brain theory" this article says the emotional system is much more complex and deeply integrated into the other systems of the brain than the TBT suggests, and the "limbic system doesn't exist" per se as there is no one emotional system in the brain.
Does the Limbic System Exist? — Brain Science Podcast
Natural Kinds Theory of Emotions
(Note Tononi is referenced here - neural Darwinism)
"... a neuroscience approach to emotion need not make the modular assumption that distinct brain regions or circuits are dedicated to instantiating instances of psychological categories such as anger, sadness, and fear.
Rather, it might be more productive to work with the assumption that emotional phenomena are instantiated in widely distributed, interacting networks. So instead of asking “Where is the brain locus of anger?”, we might ask “What are the networks that participate in the brain states that we experience as anger, or in seeing someone as angry?”. In this regard, the concept of a “neural reference space” (Edelman & Tononi, 2000) is useful.
A neural reference space is the neuronal workspace that implements the brain states that correspond to a class of mental contents (e.g., anger). Different brain states are implemented by flexible neuronal assemblies, so that a given neuron need not participate in every brain state within a class (e.g., in every instance of anger) or in the exact same mental state (e.g., the exact same instance of anger) at two points in time. According to Edelman’s neural Darwinism view (1987; Edelman & Tononi, 2000), groups of neurons compete to instantiate a mental content at a given point in time, and only one is selected to do so. According to Spivey (2007), the human brain is never in a discrete mental state but rather can be described by a fuzzy logic that allows many different states at once (each with some probability). It may be that there are different networks within the neural reference space for emotion that are differentially recruited for constituting different mental contents (e.g., anger vs. sadness vs. fear), or it may be that the space is entirely flexible. Either way, the question becomes one of functional selectivity for affect and emotion rather than functional specialization per se. "
And this paper argues for consideration of other models than "natural kinds" (Panksepp):
"Panksepp has claimed that there is strong evidence for the existence of seven architecturally and/or chemically distinct circuits in the subcortex of the mammalian brain, each of which produces a constellation of behaviors (e.g., grooming, retrieving pups, and nursing) associated with a distinct experiential state (e.g., love) and constitutes the circuitry for a discrete or basic emotion (e.g., CARE). Izard also claims seven, but his list is a bit different (for a discussion, see Ortony & Turner, 1990). Our review of the literature leads us to challenge this claim; for the sake of brevity, we will focus on Panksepp’s model (although our points apply to Izard’s model as well)."
"For almost 5 decades, the scientific study of emotion has been guided by the assumption that categories such as anger, sadness, and fear cut nature at its joints.
Barrett (2006a) provided a comprehensive review of the empirical evidence from the study of emotion in humans and concluded that this assumption has outlived its usefulness."
Of Mice and Men: Natural Kinds of Emotions in the Mammalian Brain? A Response to Panksepp and Izard
CONCLUSION
Barrett (2006a) points out that the field of emotion research finds itself in what Greenwald (Greenwald & Ronis, 1981) calls a “disconfirmation dilemma.” For every study that reports evidence that is consistent with the natural-kind view, there is more than one study that does not.
Even taking into consideration measurement error, the natural-kind model does not account for the majority of the data. It is possible to come up with reasons for why scientists don’t see the expected results in any single measure of emotion, the pattern of findings across studies is clear. Like Izard, some might argue that the natural-kind model doesn’t account for all the evidence but that it still accounts for some. And this is true. And like Panksepp, some might argue that all we need are better designs, better methods, and better measures. And again, this might be true. It all comes down to how disconfirming evidence is considered.
Classical Newtonian physics also fits our experience of the physical world. If you push something, it speeds up. If you drop something, it falls down. Newtonian equations work to describe the physical world in the majority of cases. It was the small number of cases in which these equations did not work that ignited a paradigm shift that forced scientists to rewrite the laws of physics, first with the special and general theories of relativity (to describe the movement of large bodies like stars) and then with quantum mechanics (to describe the movement of small bodies like electrons). So, the question for emotion researchers is this: How do we want to treat the disconfirming evidence in our field, which, unlike physics, is found in considerably more than a few isolated cases? Maybe it is time to take other hypotheses seriously. Barrett (2006a) was advocating that the science of emotion do just that."
