BRAIN AND IMAGINING
Should we ever succeed in making the shift,
we would be properly at home in our physical universe for the very first
time. P.M.Churchland 1989
1. imagining
I am in the small living room of our first house. I am five years old. It
is Sunday afternoon. I am alone but I can hear other people in the kitchen.
The room is dark but there is bright sunlight in a tree outside the one
small window. I have just discovered an ability I didn't know I had. It
is this: if I close my eyes I can make pieces of wood fit together to make
a birdhouse. I can see them being set together. In real life I have seen
a bluebird flying out of a binder-twine can among the farm machines in the
long grass behind the pump house, but I have never seen a birdhouse. There
is a diagram of the parts of a birdhouse in the encyclopedia and I am aware
that what I am seeing is like that diagram. What I have discovered is that
I can see it on purpose, without the picture in the encyclopedia, and I
can make it move. I can set the parts together and finish the birdhouse.
I try again. There it is. What an interesting power.
I don't remember how I happened to find this power; what I remember is the
sensation of discovering it. It was the discovery of psychic action -- a
kind of action that really happens though it isn't real. It does not change
anything in the world and no one can see it, but it is an action, because
it is something I do, and it is more completely my own action than anything
I have done before. -- Something like that.
2. cognitive order
Imagining is interesting because it is autonomous and yet coherent: it is
not a relation to the things and events around us while we are imagining,
yet it is organized as if it were a relation to things or events of some
kind. The complexity of this organization can be impressive, as when we
dream a long journey through landscapes we have never seen or work out the
planting scheme for a perennial garden. Or it can be extraordinary: Dorothy
Richardson writing Pilgrimage.
When we are perceiving we can think of the structuredness of our experience
as given by the things we perceive, but when we imagine it is clear that
the structureness of our experience is somehow our own structure. The fact
that we are able to imagine implies the existence of cognitive order and
the experience of imagining is a demonstration of the particulars of that
order.
3. mentalism and imagining
But how are we to understand cognitive order? Aristotle spoke of perceiving
and imagining as being like digestion and locomotion in being aspects of
the self-structuring activity of animal bodies. For Aristotle, cognitive
order is one kind of physical order. That was a good beginning, but without
a developed biology, there was not much more to be said along those lines.
In the long meantime the locus of cognitive order was taken to be the mind
or soul, both taken as distinct from the body. Our ability to imagine contributed
to this detour. It is a strange fact that when we perceive, we do not perceive
the means by which we perceive. It would be impractical to do so. We perceive
instead the sorts of things it has been useful to us to perceive. And when
we think and imagine it is the same: we think and imagine by means of physical
structures we are not aware of as such.
Given that we are blind to our own nervous systems in action, imagining
has seemed to be disembodied. We have tended to think of seeing as presence
in the world and of imagining as absence from it; when we imagine we seem
to perceive, and when we seem to perceive we really seem to PERCEIVE, so
we seem to ourselves to be perceiving elsewhere, off-world, 'among our thoughts',
in 'the world of the imagination', in a spirit world.
The seeming detachability of presence from physical presence is as it were
the empirical basis for mind-body dichotomies. 'The mind' or 'consciousness'
is thought of as the part of us that can be in the physical world, perceiving
physical things, and then in a dream world, perceiving dream things, and
then in a thought world, perceiving thought things.
A 'mind' or 'consciousness' thus able to perceive, think and imagine even
when it has left the physical world cannot be explained in physical terms.
Its orderedness cannot be thought of as the orderedness of a perceiving,
imagining or thinking body. What happened historically is that cognitive
order was thought of in terms of its results rather than its means, but
its results were spoken of as if they WERE means: reasoning is taken to
be a manipulation of concepts, imagining is accomplished by means of images,
and perception is an arranging of percepts. And so on. The fact that we
are able to perceive, imagine and think is taken to imply the coexistence
of separate faculties of perception, imagination and reason.
We can think of mentalist descriptions of cognitive order as a protopsychological
functionalism that was gradually arriving at useful notions of what needs
explaining. After all, we have gone on wanting to know how we are able to
perceive, imagine and reason. But mentalist descriptions are confused when
they purport to be explanations.
Some say the Senses receive the Species of Things,
and deliver them to the Common-sense, and the Common-sense delivers them
over to the Fancy, and the Fancy to the Memory, and the Memory to the Judgement,
like handing of things from one to another, with many words making nothing
understood. Hobbes, Leviathan ch. II
We shall unearth this naive ontology of images as a more or less implicit
postulate of all the psychologists who have studied the subject. Sartre
1936, 72
4. transition
The effort to construct a brain-based theory of mind can be seen as part
of the long project of slowly working our way into an understanding of ourselves
as physical creatures in inalienable contact with the universe that has
formed us. We have inherited a discussion of cognitive order that,
at least in explanatory terms, has been following a red herring for several
millennia. We have been working out the biology of cognition for only a
couple of centuries. We are in transition. With the present boom in neuroscience,
this transition has been accelerating. We are rushing toward a fully physicalist,
causal, brain-based theory of cognitive order. But our present theories
are showing the marks of transition: they are strange mixes of mentalist
and physicalist vocabulary, metaphor and explanatory style.
This attempt to put together a brain-based theory of imagining is one attempt
to get the transition right. Imagining has a long mentalist history.
It does have good currency as a phenomenological term. There is no other
word for what someone is doing when she seems to see the parts of the birdhouse
set together. The ability to do that marvelous thing still wants explaining.
But imagining probably does not have current uses as an explanatory
term: the ability to imagine is not usefully describe as being given by
the imagination. It IS usefully described as given by a combination
of general and specific organizational abilities of nervous systems.
5. naturalizing imagining
The picture of imagining I will describe here has been pieced together from
suggestions in the recent work of neuroscientists (Changeux, 1985; Damasio,
1995; Edelman, 1989; Pribram, 1991), philosophers (P.S. Churchland, 1989;
P.M.Churchland, 1989 and 1994; Dennett, 1991) and psychologists (Kosslyn,
1995). Aspects of these theories were also anticipated by Wittgenstein,
Hebb, Gibson, Langer, Sartre, Vygotsky, Piaget, and by even earlier writers
including the gestaltists and Freud.
There are three main pushes in a neural redescription of imagining. One
is an effort to revise our terminology so we speak more exactly, less mentalistically,
about what is going on when we imagine. The second is an effort to understand
what imagining is useful for, and how it could have evolved. The third is
an effort to imagine what is actually happening in a brain as we imagine
something, to picture imagining as a spatiotemporal event. These three pushes
depend on one another, but I will have to describe them separately.
6. watching how we talk
Those of us who have stopped arguing about mind-body identity are
still working our way into habits of discourse that assume it deeply enough
so that our vocabulary and structuring metaphors are no longer at odds with
that assumption. When we talk about imagining it is for instance chancy
to talk about the image, mental imagery, and image processing,
because those sorts of construction set us up. If we talk as if we are really
seeing an imagined object rather than seeming to see an object, we are next
door to thinking of ourselves as seeing a representation, i.e. as
seeing the 'internal' object by means of which we are imagining. Similarly
if we talk about image processing we are set up to think of what
we are imagining -- that birdhouse diagram -- as being the representional
structure that is being processed or transformed, rather
than thinking of the whole event -- imagining the parts of the birdhouse
coming together -- as being a process.
There is another trap in thinking of imagining as internal; the structures
by means of which we imagine are, like the structures by means of which
we perceive or initiate action, inside our skulls; but perceiving and acting
are not internal -- since they are physical relations between organisms
and parts of the world-- and seeming to perceive and seeming to act are,
as such, nowhere. The birdhouse I imagined was not in the world, not in
my head, not even in 'the imagination'. It is only when I speak of really
seeing it that I am led to wonder where it is.
I am suggesting that we talk about imagining as seeming perception and seeming
action because it works: the change in locution immediately sorts out disputes
about whether, for instance, imagining a birdhouse 'relies on' a pictorial
or a propositional format of representation. The answer of course is that
the question is nonsense. Pictures and sentences are both things we can
see or imagine, but the MEANS by which we see or imagine them are neither
pictures nor sentences -- they are four-dimensional shapes of neural activation,
which we tend to call representations.
Representation is hazardous in the same way mental image is
hazardous: it sets us up to equivocate between what we seem to see and the
unseen means by which we seem to see it. That equivocation is the founding
equivocation of mentalist theories of mind, and uncareful uses of representation
are in fact the most troubling mentalist remnants in would-be physicalist
contemporary theories of mind. Several theorists, Edelman and the recent
Dennett, try to work without it, and I will do the same.
Something that really isn't an image could be the
very thing someone is talking about under the guise of an image. Dennett 1991, 94
A person picturing his nursery is, in a certain way, like a person seeing
his nursery, but the similarity does not consist of his really looking at
a real likeness of his nursery. Ryle 1949, 72
We must carefully distinguish the mental objects themselves from the
operations and computations carried out with these objects. Changeux
1985, 133
... idealist, Cartesian epistemology of the psychologist. Edelman
1989, 13
7. seeming and sentience
There is more that needs to be said about seeming: we are able to
perceive and we are able to seem to perceive. With both perceiving and seeming
to perceive, it is as if there are two different sorts of things to be explained.
One is how we come to perceive or imagine one thing rather than another,
and the second is something about the bare fact of sentience -- how one
physical entity can see or feel, or seem to see or feel, another, even in
the simplest way. The sorts of brain theory we can see coming still have
more to say about the first question than about the second. It looks as
if we have to take basic sentience as a given, for now, and hope we know
more about how to talk about it when we know more about how we do the things
we do sentiently.
What we know already is that in a brain-based theory of cognition both percieving
and imagining are neural events and as such they are spatiotemporal shapes.
These shapes both are the EVENT of perceiving or imagining -- they are the
sentient moment -- and they are connections to other spatiotemporal shapes
in the brain.
If we don't lose sight of the fact that a sentient moment is a connected
spatiotemporal configuration, we are less likely to be puzzled about whether
sentience does any cognitive work. We can say it this way; what we think
of as cognitive work is done by structures some of which are sentience structures.
I am using the word `feeling' not in the arbitrarily
limited sense of `pleasure or displeasure' to which the psychologists have
often restricted it, but on the contrary to its widest possible sense, i.e.
to designate anything that may be felt. In this sense it includes both sensation
and emotion -- the felt responses of our sense organs to the environment,
of our proprioceptive mechanisms to internal changes, and of the organism
as a whole to its situation as a whole, the so-called `emotive feelings.'
Langer, 1988, 16
8. configuration
Although there is something basic about sentient perception that we have
to take as given even while knowing we don't know how to talk about it,
we are pretty sure we know why we have it ( --are it): we are able to perceive
because abilities that are its precursors helped keep our ancestors alive.
It sometimes has that use for us too.
Is it equally clear what imagining is for? It is likely that imagining and
perceiving as we know them are so similar in their use of more basic cognitive
capabilities that they have mostly the same cognitive precursors. Maybe
we are able to imagine solely because we are able to perceive. What is more
likely is that we can also perceive because we can imagine. I will describe
some of the functional interrelations of perceiving and imagining in a later
section.
I have said that in a brain-based theory of cognition perceiving and imagining
are neural events and as such are spatiotemporal shapes connected to other
spatiotemporal shapes. We do not have anything like a completed neuroanatomical
map, but we do know that nervous tissue can do what it does because it is
organized in specific ways. The nervous system is configurational: it is
a configuration of nervous tissue distributed throughout other sorts of
tissue in animal bodies. Both its localization in those bodies and its connectivity
across regions of those bodies are important. By means of them it supports
other more transient configurations, whether of energy, motion or chemical
substances -- the structured electrochemical states that build themselves
within and around neural connections.
We haven't settled how best to talk about the building up and melting down
of these organic forms in and around the nervous system. We are in the midst
of trying out metaphors. Pribram (1991) talks about the construction of
holoscapes. Churchland (1989) talks about thermodynamic settling into positions
or trajectories in state space. Varela (1984, 219) talks about shifting
dynamical landscapes. All of these ways of speaking have the advantage that
they encourage us to think of a cognitive event in physical terms.
9. computation as consequential configuration
A more ambiguously useful metaphor is the computer metaphor. It is difficult
to use the computer metaphor clearly; our understanding of mechanical computation
tends to import the mentalist equivocations we fall into when we use the
notion of representation, since we have been defining computation as the
processing of representations.
There is a better way to understand cognition as computation, a use of the
computer metaphor that by-passes the usual identification of computers with
the formal systems they are meant to automate, and instead emphasizes the
physical properties of computing mechanisms that allow them to derive logical
consequences among others.
The nervous system's changing acts of spatial structure may be thought of
as computation if we think of computation itself as systematic pattern transformation
made possible by the connective design of a machine whose physical materials
have stable dynamical properties. This description is of course true of
computation with digital machines, but it is easier to notice with analog
or parallel processors. Mechanical computation is systematic consequential
connection. In a nervous system systematic consequential connection has
to do with coordinating an organism both internally and externally.
Coordination must be both spatial and temporal. Nervous system activity
must be relevantly simultaneous -- correctly distributed into many cooperating
regions -- and relevantly sequenced, again in such a way that simultaneous
activities will be timed correctly in relation to each other and in relation
to events in the world. Complex spatiotemporal coordination is what mechanics
and organics have in common; it is what supports the usefulness of a computational
metaphor in the first place.
If imagining is sensory simulation -- as I am about to argue -- and if we
think the function of sensory simulation is to set up downstream (or upstream
or sideways) connections, and if we understand computation as systematic
consequential connection, then we can say imagining serves computational
purposes -- is a form of computation. Connectionist models of computation,
which are grounded in an understanding of computation as physical pattern
transformation, are extremely useful in helping us think about styles of
pattern transformation the nervous system may be using (principal-components
versus competitive mappings between unit layers, for instance) and thus
they carry us into the specifics of understanding how cognition is embodied.
But our difficulties with the notion of representation tend to follow us
even into connectionist pictures, and so for the purposes of this paper
I will try to integrate connectionist contributions without calling them
computation.
Unsupervised learning algorithms can be classified according to the type
of representation they create. In principal-components methods, the hidden
units cooperate, and the representation of each input pattern is distributed
across all of them. In competitive methods the hidden units compete, and
the representation of the input pattern is localized in the single hidden
unit that is selected. Hinton 1992, 150
10. sensory simulation
The medieval distinction between intuitive and abstractive cognition was
a distinction between perceiving and imagining. Intuition, or immediate
apprehension, is situational contact: a transaction between a perceiver
and a perceived. Abstractive cognition is anything else, including such
activities as remembering and planning, which have situational relevance
but are not an instance of physical contact between an imaginer and whatever
she is imagining.
When we are thinking of any sort of cognitive structure as a spatiotemporal
shape of coordinative connection, the difference between perceiving and
imagining will be harder to specify. We could try saying perceptual structure
is relevantly responsive to the physical presence of something in the world.
Many descriptions of perceptual structure mention as part of the notion
of structure relevantly responsive to the presence of the observed, some
form of dynamic contribution from the object. Varela (1984, 220) speaks
of a perceiver convolving its own and a received structure, Pribram (1991,
4) of a dynamic matching procedure between sensory input and the brain's
microprocesses, Freedman (1991, 78) of the evolution of a dynamical system
toward attractors picked out by patterns of input.
Describing perceptual structure as neural structure that is relevantly responsive
to the physical presence of something in the world has the advantage that
it invites an extension of the notion of perceptual structure into sensory-motor
and other downstream (and upstream and sideways) connections that constitute
the perceiver's readiness to feel, act, remember, think, move, say something,
look at something else. Perceptual structure can thus be thought to extend
seamlessly outward from a sensory core.
If we define perceptual structure as having something to do with relevant
response to something physically present we could say a similar structure
evoked WITHOUT triggering or structuring input from something physically
present is a simulational structure -- is perceptual simulation.
Where cognition is imagined as manipulation of codes by digital computers
the notion of simulation does not have easy purchase, but if we think of
cognition as inherently configurational consequential connection, the notion
of simulative configuration makes immediate sense. If we can think of a
coyote as neurally configured to bark when it sees the moon, it makes sense
also to think of the coyote barking when it is neurally configured to seem
to see the moon -- when it is set up, at least partially, as if it were
seeing the moon.
So if we think of any form of cognition as connective configuration, and
if we think of imagining as sensory simulation, then we are a small step
from guessing why imagining is elaborately developed in complex-enough creatures
-- it is a way of setting up neural connections in perceptual structures
so that they in turn can set up neural structures of other kinds, which
may themselves set up yet other connections. Imagining structure, like perceptual
structure, will extend seamlessly outward into connections that constitute
the imaginer's readiness to feel, act, remember, think, move, say something,
look at something -- or to seem to do any of these things.
Understood as sensory simulation, imagining can be seen to have lots of
kinds of uses. Dennett suggests that human neural systems use seeming to
hear a sentence as externally-patched access to instruction-following routines
(" Alright, now I have to turn left at the corner, and then I have
to look for the Mobil sign on the south side of the street"). Damasio
guesses that our brains use seeming emotional/somatic response to mark as
desirable or probably harmful possibilities of action we are considering
( I felt so awful when I thought of visiting my relatives that I didn't
go -- even though that awful feeling was not really a bellyache, only a
cortically simulated seeming bellyache).
A perceptual system that has become sensitized
to certain invariants and can extract them from the stimulus flux can also
operate without the constraints of the stimulus flux. Information becomes
further detached from stimulation.. The adjustment loops for looking around,
looking at, scanning, and focussing are then inoperative. The visual system
vizualizes. But this is still an activity of the system, not an appearance
in the theatre of consciousness. Gibson,
1966, 256
All that has to be the case for this practice to have this utility iis
for the preexisting access relations within the brain of an individual to
be less than optimal. Dennett 1991, 195-6
11. nonsensory simulation
I will note that the category of neural simulation is larger than that of
sensory simulation: many kinds of neural connection don't involve sensory
tissue at all, and yet they can be simulational. Grush (1995, 37) and Jeannerod
talk about motor short-loop circuits which provide efferent motor networks
the feedback they would probably have had if there had been time for such
feedback to arrive. Such feedback need not reach sensory areas: it may be
thought of as a motor 'image' (Jeannerod, 1994, 187) without being imagined
muscular sensation. A similar extension of the idea of simulation into nonsensory
simulation can make sense of Freud's mysterious posit of unconscious images:
if sensory neural response can be set up in the absence of its usual or
proper occasion, presumably nonsensory neural response can also be set up
in the absence of an appropriate trigger, and thus we can behave in the
presence of a husband as if we were in the presence of a father without
being aware that we are doing so. 'Image' here can be read as meaning simulatory
structure, and 'unconscious' can be taken to mean nonsensory.
12. wide nets: generic cognitive structure
In (5) I said the three main pushes in a physicalist redescription of imagining
are watching how we talk, getting an understanding of what imagining is
for, and working out some sort of spatiotemporal picture of what is happening
in a brain when we imagine. I have not been able to talk about the first
two of these efforts without describing cognition as widely connected consequential
configuration, so part of the work of this section is already done. When
we think of a brain imagining, a widely connected neural configuration is
what we have to imagine. Given the limits of our knowledge we cannot believe
that we are imagining it correctly, but even a very approximate version
will have the advantage that it imagines an embodied event AS embodied--
as spatiotemporal, causal, historical and embedded in the world.
Neural theorists whose work I am citing offer similar visions of the wide
network as generic cognitive structure. Changeux (1989, 24-5) speaks of
neuronal graphs he sees as spider's webs set up both vertically,
from spine through midbrain to cortex, and horizontally, across cortical
regions. Pribram (1991, xxviii) talks about temporarily stable states which
are mappings of isopotential dendritic polarizations. Edelman (1989, 195)
defines a category, by which he means a generic perceptual/conceptual
structure, as a thalamocortical reentry system involving primary and secondary
sensory areas, association cortex, and cortical appendages. Damasio (1995,
102-5) talks about strengthened systems which are global mappings,
strongly related by circuit design, linking meshes of topographically organized
nets in early sensory cortices with non-topographically organized but systematically
interrelated convergence zones in higher-order association cortices, basal
ganglia and limbic structures.
The mental object is identified as the physical
state created by correlated, transient activity, both electrical and chemical,
in a large population or `assembly' of neurons in several specific cortical
areas. This assembly, which can be described mathematically by a neuronal
graph, is discrete, closed, and autonomous, but not homogeneous. It is made
up of neurons possessing different singularities laid down in the course
of embryonic and postnatal development. The earmark of the mental object
is thus initially determined by the mosaic (or graph) of neuronal singularites
and by a state of activity in terms of the number and frequency of impulses
flowing in the circuits they form. Changeux,
1985, 137-8
Human emotion is phylogenetically a high development from simpler processes,
and reason is another one; human mentality is an unsurveyably complex dynamism
of their interactions with each other, and with several further specialized
forms of cerebral activity, implicating the whole organic substructure.
Langer, 1988, 9
13. sensory ratio
Changeux talks about the members of our old cognitive classification --
percepts, images and concepts -- as cognitive structures different not in
kind but in degree of sensory involvement: a concept would be a neuronal
web or graph whose sensory ratio is low, whose neural population was dispersed,
multimodal or amodal. If we visualize the event of imagining as a wide net
with areas of activation in many regions of the brain, we can see immediately
that different kinds or moments of imagining could also have different degrees
of sensory involvement. There could be fleeting hypnagogic activations that
are purely and simply visual and implicate very limited areas of early visual
cortex -- circuits in layer VI perhaps (Zeki 1992). Or there could be multimodal
hallucinations implicating both early sensory and associational areas in
occipital, temporal and parietal cortex. Or there could be a wide net with
complex but nonsentient activation in frontal association cortex and a limited
involvement of sensory-motor areas (someone plotting a chess move?).
Visualizing the imagining or perceiving or thinking moment as a wide net
has another kind of payoff -- it is instantly obvious that we could be thinking,
perceiving and imagining at the same time. This lets us catch up with Ryle,
Wittgenstein and the Romantic poets, who long ago noticed that fact. An
episode of seeing-as, or seeing an aspect (Wittgenstein 1953, 213, 210),
or seeing my doll smile when it isn't smiling (Ryle 1949, 74), or having
ideas of full sail modifying the impression of the naked masts (Coleridge
1957, 2340) can be handled by envisaging degrees or strands of simultaneous
activation in various cortical regions. The sort of interpenetration which
interests Mary Warnock -- imaginative presences of past perceptions enriching
the present moment's experience (1976, 150 ) -- can similarly be thought
of as multiplex simultaneity of activity in a wide net.
Faculty divisions rightfully founder in the face of the coordinative unities
of cerebral connectivity, and in the face of the unity of the felt subset
of these connections which is the experienced moment. Sensing, imagining
and thinking are alike in being aspects of the function of wide nets of
neural activity: they make varying use of the same or similar substructures.
They are subserved by the same bases of cognitive capability.
[A concept] contains only a small sensory component
or even none at all, because it is the result of neuronal activity in association
areas such as the frontal lobe (where multiple sensory or motor modalities
are mixed) or in a large number of areas in different regions of the brain.
Changeux, 1985, 138
14. semantic topography
Where the abilities once classified as psychological faculties are seen
as very loosely categorized kinds of global uses of what is in fact one
organ, we are more likely to think of cognitive capability of any kind as
grounded in characteristics the nervous system has as a whole, characteristics
that are the functional preconditions for imagining as they are for thinking
and perceiving. The most basic of these characteristics is what we could
call the brain's intrinsic semantics. The wide net of activity that is the
event of an imagining moment is set up across what Changeux calls a mosaic
of neuronal singularities. The brain just is a little region of inherently
semantic material whose topography, evolutionarily given, developmentally
tuned, and individually fitted by a life-time's net-training, supplies us
with a ground of semantic possibility. Activation of a neuronal graph in
this landscape is an event of content discrimination (in Dennett's nicely
neutral term) which is
differential -- a pattern in physical space is a position in cognitive state
space.
We know that with one pattern of activity in the olfactory bulb we will
smell pine and with another we will smell raspberries (see Freedman 1991).
When we have isolated the microcomponents of smell identification and shown
how pattern analysis by layers of units can pull them apart every time,
we still don't know why THIS pattern is smelling pine and this one is smelling
raspberries. We do know, generally, that it has to have something to do
with the way sensory receptors map onto adjacent spaces which map onto each
other. Studies of cerebral morphogenesis are giving us a clearer picture
of how such spaces flower outward from initial cell clusters and retain
traces of the structure of their origination. Certain kinds and levels of
activation in primary and secondary sensory cortices are sensory discriminations
the way certain kinds and levels of activation in motor cortices trigger
muscle contractions, because of the ways they are connected to the rest
of the body and by means of that body to the rest of the world.
If we imagine a brain embedded in the world in this way -- if we visualize
its connectivity extending beyond an animal's skin into the world -- we
are probably in a better position to begin to think about how the brain
can be an intrinsically semantical piece of physical space. One of the risks
of calling differential activation of some region of the brain a 'symbolic
representation ' (as Crick and others do ) is that we lose sight of the
fact that what is being called a symbol is in fact anchored in an organized
physical space which is semantic because of the ways it in turn is embedded
in the physical space of the world -- when we call it a symbol we tend to
think of it as a little object whose physical position has no importance,
and as soon as we do that we have to be mystified by how it can possibly
refer or designate.
All behavior, all sensation, is explicable by an
internal mobilization of a topologically defined set of nerve cells, a specific
graph. The `geography' of this network determines the specificity of the
function. Changeux, 1985, 124
15. structural retention
Where a particular spatiotemporal shape is a particular relatedness to the
world, maintaining a relation will require maintaining a shape; maintaining
a potential for relation will require fixing a potential shape; modifying
a relation will require modifying aspects or parts of a shape; and restoring
a relation will need a mechanism for reactivating a shape.
An imagining moment will be a shape that is temporarily stable and that
is a particular coalition of shape-parts that were latent and have been
triggered on this occasion. A brain-based picture of cognitive order has
to start at this level: we have to talk about neural stabilization and recruitment,
structural modification and retention, and reactivation triggering.
A pattern of neural activity has to settle -- it has to come to a decision
within its space of semantic possibilities -- and then it has to hold that
shape long enough to affect other shapes relevantly. Crick (1992, 157) mentions
60-70ms. as a minimum processing period for extended cell assemblies. What
he calls iconic memory -- which we might experience as an afterimage
-- could be effected by stabilities lasting less than a second, but what
is often called working memory -- which we might experience as keeping
something in mind -- would be a shape held for several seconds, or longer
if it is refreshed by the use of tricks like repeating a telephone number
aloud. When we are looking at the world there are stabilities given by constancy
of input from objects that aren't changing much -- we could say we are neurally
entrained by the object. When we are imagining we are not so entrained and
we are able to hold shapes only briefly. Then neural circuits will be entirely
self-stabilized, and here the imagining moment has its main value as a window
onto the dynamics of neural self-organization.
If imagining is perceptual simulation -- perceptual self-structuring in
the absence of perceptual input -- the nervous system will need to be able
to fall into shapes it has learned in perceptual encounters: it will have
to have inscribed itself with lasting structural changes. In a net, structural
modification will be modification at the nodes: synaptic modification. And
synaptic learning will have to be selective -- it will have to fix synaptic
change so that overall shapes of activity are inscribed. Hebb long ago (1949)
suggested this learning rule: synaptic connections between cell assemblies
that are active together will be modified to retain those connections.
16. structural assimilation
Along with an explanation for how cognitive shapes are fixed we have to
have an explanation for how they may be relevantly modified. Cognitive abilities
develop; we extend abilities we already have into new circumstances. Piaget,
who was impressed with the orderliness of change in cognitive ability, saw
that he could posit something like Hebb's rule as a mechanism for cognitive
development as well as for structural retention. He envisaged increasingly
inclusive neuron-enlisting processes that he called schemas of assimilation
(in Piattelli-Palmarini 1980, 92); if we have a circuit established for
putting our finger in our mouth, it can assimilate nearby circuits simultaneously
activated by the presence in our baby hand of other objects. Hebbian learning
will then cause them to be coactivated at other times. And so on, with increasing
orders of generality, so that next the putting-in circuit will enlist another
destination as well as another object. The baby puts a toasted cheese sandwich
into the VCR. Here we'd have to tell a story about inhibitory learning too.
To explain imagining we will also have to say something about how perception-like
structure can be set up in the absence of perceived objects: we will need
a mechanism for reactivation-triggering. Again, Hebb's rule can be invoked.
If perceiving has had wide-spread connections into language and association
areas, then those areas will have learned connections with perceptual structures.
Activity in those areas will be able to seed some of the shapes we are when
we perceive.
It will have to be able to do so partially and selectively, in what can
be called a content-addressable way. It will have to be able to reconstruct
wholes given parts, but it will also have to be able to evoke parts given
other parts. If imagining recruited too much perceptual structure we would
be hallucinating.
Memory means simply that if in this model system
you put a pattern of firing onto a number of the neurons, then either a
different pattern comes out or, in special cases, the same pattern comes
out because the system regenerates it. In this ... case if you put in a
small amount of that pattern it will run around and produce the whole pattern. Crick 1988, 533
In such a reciprocally acting set of systems, input triggers an operation
that at any moment is largely self-determining ... Further, the larger the
amount of experience stored in the systems operating in a top-down fashion,
the greater the self-determination. Thus Beethoven ... Pribram, 1991,
4
17. imagining, logic and creation
The wide net embodying an imagining moment is a semantic structure inasmuch
as it touches into cerebral areas connected to sensors and effectors, but
it is semantic also in the discriminations it accomplishes across areas
and across layers within an area. Layer-to-layer and cross-regional transformations
can be thought of as accomplishing logical functions.
Physically speaking, mappings between neuronal groups are filters, amplifiers,
transducers, sets of gates; logically speaking, since they accomplish a
sequence of decisions within an intrinsically semantic physical material,
they are performing something like induction, deduction, feature abstraction,
nested generalization, higher-order description. A moment of perceptual
discrimination may thus be thought of as setting up instantly and automatically
a whole range of classificatory possibilities. The logical relations embodied
in its extensive connections may include descriptions in terms of properties,
of parts, of class inclusion, of opposition within a class. A perceptual
discrimination could even be thought to reach into very high-order mappings
that amount to subsumptions under physical laws that have never yet been
articulated -- a physical fine-tuning we'd call scientific intuition.
I am invoking a picture of physically embodied high intuition because the
fact of imagining experience that most impresses novelists and other visionaries
is its creative coherence -- the depth of semantic order possible in cognitive
structures which are experienced as entirely self-produced. If there are
layers of perceptual structure which are discriminations of properties of
so high an order that they amount to descriptions at the level of physical
(or social, or cultural) law, then activation organized from this level
might be experienced as creation from first principles -- creation with
great semantic depth. This gives us a cognitive account of the Romantic
distinction between Fancy, which was superficially associated sensory memory,
and Imagination, which was principled creative synthesis (Coleridge, Biographia
Literaria II, ch. XIII).
A specific image or belief is just an arbitrary
projection or slice of a deeper set of data structures, and the collective
coherence of such sample slices is a simple consequence of the manner in
which the global information is stored at the deeper level. P.M.Churchland 1989, 109
The so-called concepts of extension, of far and near, gravity, rigidity,
horizontal, and so on, are nothing but partial abstractions from a rich
but unitary perception ... The parts of it he can name are called concepts,
but they are not all of what he can see. Gibson 1966, 261
18. backstage connections
Although they speak of the wide net of a perceiving or imagining moment
as ramifying almost anywhere in the brain, Damasio and others tend to make
a critical distinction between structures in sensory areas and structures
they think of as doing backstage work. Damasio calls these backstage connections
dispositional representations (1994, 241-2) because they are dispositions
to respond to perceptual structures or to trigger them as simulations: prefrontal
cortices in particular will be suitable locations for dispositional representations,
he thinks, because they are well connected to and from both sensory and
nonsensory areas, as well as to and from bioregulatory old-brain structures
and nuclei controlling neurotransmitter distribution -- structures Damasio
thinks of as supplying motivation and feeding outward into motor and chemical
response. For Damasio, imagining would thus be vitally motivated centrally-organized
activation in sensory maps. Both Damasio and Edelman (1989, 195) call these
activations images and seem to speak as if they exist primarily as
an interface with the imaginer, while dispositional representations out
of sight do the work of cognition. This curious mentalist remnant is most
obvious in Crick who says, for example, 'Some of these neurons would be
involved in doing computations -- trying to arrive at the best coalitions
-- while others would express the results of these computations, in other
words, what we see!' (1992,155).
It is one thing to say brain structures can have cognitive effect even when
they are nonsentient, or to say the sentient aspects of perceptual or imagining
wide nets are triggered or organized out of these nonsentient configurations.
But it is something else completely to speak of the sentient parts of perceptual
or simulational structures as being DISPLAY structure. The persistence of
this notion in otherwise hip theorists is presumably one more instance of
the representation equivocation that slips between what we see or seem to
see and the means by which we see or seem to see it.
The way to say it is this: we perceive and imagine by means of neural structures
parts of which are sentience structures. There is functional continuity
between felt and unfelt processes. Sentience structure and cognitively effective
structure will overlap but not coincide: sentience structure will be a subset
of cognitively effective structure. Sentience. structure will not be some
'mid-level description' 'projected into consciousness' but will instead
be working structure as actively involved as nonsentience structures in
basic cognitive tasks: the structures by means of which we are seeing and
imagining will ALSO be sorting and passing activation.
Signals arising in those images are relayed to
several subcortical nuclei and multiple cortical regions which contain dispositions
for response. Damasio 1994, 241
..accounts for the importance of preconscious processes in the construction
of such elaborate phenomena as ideas, intentions, images and fantasies,
and makes it not only reasonable but obvious that they are rooted in the
fabric of totally unfelt activities. Langer 1988, 8
It seems obvious that the purpose of vivid visual awareness is to feed
into the cortical areas concerned with the implications of what we see.
Crick 1992, 157
19. subsystem relations
If we imagine the structures by means of which we imagine as wide nets.
we can begin to ask more interesting questions about exactly how imaging
is done. Kosslyn's Image and Brain (1995) is an attempt to work out some
of the specifics of what a brain would have to do to set up and use perceptual
simulation. Although Kosslyn writes in the idiom of computer functionalism,
he has several suggestions about what he calls implementation. His guess
is that 'imagery' involves 'a relatively small number of processing subsystems
that are drawn upon in different combinations for different tasks' (396).
The 'central core' of a subsystem, by which Kosslyn means an input-output
mapping that performs something we can recognize as a distinct subfunction,
as, for instance, color discrimination is an identifiable subfuction in
a visual system, tends to be implemented in local tissue, Kosslyn guesses
(31), but it may also have diffuse outlying connections. Since subprocesses
feed backwards and forwards onto one another, and since participating subsystems
are active concurrently and continuously, cross-regional settling can be
thought of as cooperative in the same way neural settling in local networks
is cooperative. What we think of as distinct subfunctions could thus overlap
spatially -- they would share tissue. A single subsystem can also be multifunctional,
passing activation simultaneously into a number of other subsystems. There
could also be alternative routes through processing space -- the same global
input-output mapping could recruit different subsystems at different times
(51).
Given this picture of imagining as a fluid and multimodal confederation
of simultaneously active multifunctional parts, the sorts of questions we
ask about the relation of perception and imagining shift level so that we
are less interested in the traditional contrast between two terms than we
are in the ways they are functionally interdependent.
20. perceiving as imagining
The brain-based theories I have been describing offer variations on the
notion that perceiving and imagining require an integrated theory because
they are similar functions performed in what are largely the same structures.
As a consequence, most brain-based theories of mind concentrate on trying
to understand perception, on the assumption that an understanding of perceptual
simulation will fall out of a theory of perception. Kosslyn, who has committed
many years to studies of visual imaging, is now saying (1995) that a theory
of visual object recognition is the necessary foundation for a theory of
visual mental imaging; but he is also saying that perception requires the
use of simulational structure, and that in fact our ability to imagine may
derive from abilities already employed in ordinary object perception.
Kosslyn thinks our ability to seem to perceive originates in neural anticipation:
a well learned perceptual sequence, which makes it possible for us to see
moving objects quickly enough, runs ahead of its input. Dennett similarly
invokes simulation as part of the rudimentary work of perception, as when
a hunter must keep track of an animal that disappears behind a bush (1991,
191). Freyd offers experimental evidence of what she calls representational
momentum -- a rapid mandatory mechanism (1988, 432) that leads people
to remember interrupted actions as having progressed further than they had
in fact progressed when they were interrupted. (This sort of perceptual
extrapolation is not far from the sort of ordinary pattern completion capability
hidden unit processors can supply to noisy input.) Perceptual tracking,
priming, anticipation and perseveration can all be seen as precursors of
our ability to sustain seeming to perceive independently of sustained sensor
input.
In perception, if one anticipates manipulating
an object, the appropriate representation in the pattern activation and
spatiotopic mapping subsystems are primed. In imagery, the priming processes
are so strong that a mental image is generated, and this image moves through
the sequence one anticipates seeing. Kosslyn,
1994, 351
21. does imagining use perceptual tissue?
Damasio's hypothesis, like Kosslyn's, is that our experiences of imagining
are the result of structures activated in topographically organized areas
of early sensory cortices (98, 101). Edelman similarly guesses we will find
that they result from 'reentrant engagement of perceptual categorial systems
even down to primary receiving areas' and including secondary sensory areas
(1988, 195). Changeux is tempted, he says, to suggest that perception and
imagining 'share the same neural material base,' and constitute 'different
forms or states of the same basic material infrastructure' (1989, 132-133).
-- are both 'neuronal graphs recruited principally from the maps or homunculi
of primary and secondary cortices' (138). Farah says 'mental images' 'rely
on the same neural substrate as perceptual images generated during normal
perception' (1989, 188).
The easy assumption that imagining and perception share the same mechanisms,
or more specifically, that imagining operates back onto primary and/or secondary
sensory cortices, is supported by evidence of a number of kinds. There is
a variety of psychological testing evidence, some of it quite old. Changeux
cites Perkey's 1910 experiment showing that test subjects reported they
were imagining when in fact a subthreshold image was being back-projected
on a screen they had been instructed to fixate. Other results (Segal and
Fusella 1970) showed competition effects when subjects were asked to perform
visual perception and visual imaging tasks at the same time; these competition
effects were not present if perceiving and imagining tasks were performed
in different sensory modalities. Kosslyn (1994, 328-9) cites evidence that
there are parallels in the ease or difficulty subjects experience in tasks
they perform both while perceiving and while imagining. Similar sorts of
after effects and illusions are experienced in both perceiving and imagining
conditions.
Martha Farah's 1988 survey of neuropsychological findings concludes that
two lines of recent evidence reliably localize brain activity during visual
imaging tasks to visual cortical areas. Regional cerebral bloodflow analysis
and brain electrical mapping show activity in the same regions of vision
cortex when subjects perform similar vision and imaging tasks. Tasks requiring
imaging in another sensory mode do not activate these areas. Second, psychological
testing data imply shared functional mechanisms for visual imaging and visual
perception. Evidence described shows parallel sorts of deficit in perceptual
and imaging tasks following cerebral damage. Someone with cortical blindness
cannot visualize, while someone whose blindness is peripheral can. Selective
imagery deficit IN ALL CASES, Farah says, parallels visual deficit. Acquired
color blindness applies also to imaging; inability to localize objects,
or to recognize them, will be found equally in perception and imaging tests;
visual neglect of a single hemifield will extend to similar imaging neglect;
a difficulty with face recognition will extend to face recall.
Changeux mentions studies indicating that direct stimulation of neurons
in the primary visual cortex produces simple visual hallucinations while
direct stimulation of neurons in the secondary visual cortex sets off more
complex hallucinations of changing scenes ( H. Haecan and M. Albert, 1978,
Human Neuropsychology).
Kosslyn points out that Bain in 1885 and James in 1891 were already suggesting
imagining is simulative use of perceptual neural structure. Without the
more detailed knowledge we are beginning to have of the actual organization
of connectivity in the brain, it was not possible, however, to say much
more than that when we perceive, structures in sensory areas are activated
from the sensory periphery, and when we imagine they are 'centrally activated'.
'Central activation' is still to some extent a wave in the direction of
terra incognita, but brain-based theorists of imagining are beginning to
think about what else might have to be active in an imagining episode's
wide net, both to set up a sensory simulation and to use it. Kosslyn suggests,
for instance, that, in order to organize ourselves to imagine we are seeing
an object rotate, we may have to simulate seeing an object as we move around
it. That is, sensory simulation may at times have to be organized by means
of a motor simulation which is not experienced as such.
22. imagining and awareness
We aren't always conscious although our brains are always active. Even when
we are awake not all neural activity is sentient: people respond to stimuli
they do not notice. We know only a little about what makes the difference.
It has something to do with rate of activity, with duration and with location.
Libet reports (1991, 1753) that a minimum duration of appropriate neural
activity of up to about .05s is needed for people to sense a stimulus whose
intensity is low, although durations below that minimum can mediate response.
And there is a trade-off between duration and stimulus intensity, within
certain limits. Where stimulus intensity is greater, cerebral on-time can
be less. Crick suggests awareness is tied to rate of neural activity: neurons
will respond to the same things whether we are awake or asleep, but fire
more strongly when we are awake and attending -- and less strongly when
we are awake but responding to something else. Thus, he proposes, timed
bursts of activation from the thalamus that boost firing rates throughout
the whole of a wide net of activity could coordinate awareness.
I have been assuming throughout this paper that all consciousness is sensory:
that only those structures are sentient which are the structures by which
we perceive or seem to perceive, and that forms of consciousness we think
of as nonsensory (thinking, reasoning, etc.) are conscious only to the extent
that they include sensory structure. The kinds of sensing and seeming to
sense involved may include proprioceptive awareness of tissue states and
physical tensions, as Damasio and Langer suggest. In humans conscious states
can rely heavily on seeming to hear ourselves speak, as Dennett suggests.
If the thesis that consciousness IS sensory engagement turns out to be true,
a theory of sensory simulation will be a key to the general theory of consciousness.
One of the questions current in philosophy of mind (for instance Jackendoff
1991) concerns the 'level of description' that is 'projected into consciousness'
when we perceive or imagine. The question has a mentalist sound, but if
we interpret it charitably we can take it as a question about whether all
or some or only one or two of the mutually mapped layers in sensory cortices
are bearers of the activity by means of which we perceive or seem to perceive.
This is a fair question. Dennett has crusaded for a picture of sentience
as distributed in the brain, 'events of content discrimination' being accomplished
wherever they happen to happen -- color discriminations, motion discriminations,
form discriminations, identity discrimination, name discriminations -- the
lot. The wide net of a perceiving or imagining moment would be a standing
mosaic of mini-micro-discriminations, some of which are taking place (at
adequate rates and durations of activation) in sensory areas -- and those
microdiscriminations would be the standing texture of conscious experience.
Feature detections or discriminations only have
to be made once ... the information content fixed does not have to be sent
somewhere else to be rediscriminated. Dennett
1991, 113
All varieties of perception -- indeed all varieties of thought or mental
activity -- are accomplished in the brain by parallel, multitrack processes
of interpretation and elaboration of sensory inputs. Dennett, 1991,
111
23. transparency of the imagining moment
If we think of cognition as shapes of activation in a brain, and if we think
of ourselves as BEING those shapes of activation, we can begin to think
fruitfully and interestingly about what our present moment's experience
might imply about its own neural means.
People who speak in terms of neural representations must -- because of the
temptations implicit in their metaphor -- continuously remind themselves
that introspection of representational structures is impossible. But this
is just to say that seeing is not seeing the means by which we see, and
neither is seeming to see. Of course we cannot introspect the means by which
we perceive or imagine. We cannot introspect at all: we can only perceive
or imagine.
But when we imagine cognition as wide nets of activation, we can begin to
take any perceiving or imagining moment as an immediate expression of its
means. The more we learn about the brain's organization, the more transparent
the cognitive moment will be. It is already temporally transparent: we know
that the timing of cognitive events is precisely coordinate with neural
events, since they are the same thing. And there are other quite general
things we can know, for instance that when we are awake some exact neural
condition prevails and when it ceases to prevail we are asleep. As we know
more about neurotransmitters we will be able to say something about our
neurochemical state, just as we (some of us) are already able to notice
our own estrogen levels. Perceptual illusions such as subjective contours
can always be taken as implying pattern-completion activity in form-discrimination
areas of visual cortex. ANYTHING we are aware of would imply a certain level
of neural activity in sensory cortex somewhere. When we notice the sorts
of things a meditator might notice, that the sensation of thinking involves
subtle forms of motor fantasy, perhaps, we could assume structures active
in sensory-motor areas as we think; and that could tell us something about
how our conclusions are being processed in nonsentient areas. A particularly
vivid dream could imply high levels of well-organized structure. We would
be able to notice sensory blends or ratios as such. We would have a theoretically
supported expanded phenomenology for kinds and tones of sensation we ignore
because we do not name them. Perhaps we will discover there are ways we
ARE able to perceive the means by which we perceive: perhaps there is proprioception
at the level of neural configuration. Perhaps we are already feeling shapes
in our brains.
These sorts of possibility seem to give more joy to artists than to philosophers,
but it is a kind of joy philosophers could learn. Strawson in his 1971 paper
on the notions of perceiving and imagining in Kant and Wittgenstein describes
an 'actual occurrent perception' infused with the thought of other past
or possible perceptions of the same object'-- a moment that were it seen
as a wide net would be understood as implying the coactive presence of simulational
and perceptual structure.
... non-actual perceptions are in a sense represented
in, alive in, the present perception. The actual occurrent perception ...
is, as it were, soaked with, or animated by, or infused with -- the metaphors
are a choix -- the thought of other past or possible perceptions of the.
same object. Strawson 1971, 88-89
Experience clearly gives no clue as to the means by which it is organized.
Lashley 1956, 4
[A midlevel description] may, as it were, give the phenomenological mind
the cue to produce experiences of blue at the right times and experiences
of red at the right times. But that is not the same as producing the experiences
themselves. Jackendoff, 1989, 18
... more like the flow of a river in which patterns emerge and disappear,
than a static landscape ... contents aren't contained anywhere but are revealed
only by the dynamics: form and content are thus inextricably connected and
can't ever be separated. Kelso 1995, 5
[There is no way to isolate the properties] presented in consciousness
from the brain's multiple reactions to its discriminations, because there
is no such additional presentation process. Dennett 1991, 393
Rising from a background of general bodily feeling and a texture of emotive
tensions so closely woven that the separate strands of process in it are
not distinct, but compose a `mental state' ... more specifically articulated
acts [are] felt as envisagements, intentions, cogitations, insights, decisions
... Langer 1988,12
24. imagining and metaphor
We know we use metaphors; we know, further, that everything we are able
to do we are doing by neural means. In my reading a metaphor, like any simulational
structure, is a temporary configuration, a little net within the larger
net of the moment's cognitive activity. It distributes activity in many
directions; it is a bridge, a switching structure. It will use sentient
tissue, when it does, because that structure already has working, not-wrong,
connections with action, language and emotion.
It would be useful to have a more exact sense of how we use a metaphor.
We are thinking about one thing in terms borrowed from our knowledge of
another thing. Can we translate this into neural terms by saying that when
we evoke neural configurations relevant to two different objects we are
superimposing two physical structures and thereby setting up a processor
that convolves their connections in some way? Evoking two nets simultaneously
could create what amounts to a filter, as certain connections are strengthened
and others cancel out. The convolved structure that results would distribute
activity in ways relevant to both contexts, perhaps in unusual ways. The
moment of metaphor-experience would be the result of the parts of that mixed
structure that touch into sensory tissue; we'd experience ourselves, as
we do, as imagining-cum-thinking.
If in fact this is how we use metaphor, helping ourselves to a clearer picture
of a brain in the act of picture-thinking could help us figure out how philosophers
go wrong. Consider the metaphor used by this philosopher:
There is an imagination; it is a faculty or power;
specifically it is a faculty for internal representation; these
representations are image-like; therefore they share a
certain character with external images; in particular, like
material images they represent absent objects as present;
they do so by means of resemblance. (Brann 1991, 5)
What sort of cognitive landscape could be responsible for this description?
--Not that it is wrong. Everything said can be construed in a way that makes
it make sense. 'There is an imagination': we are able to imagine. 'It is
a faculty or power': ditto. 'Specifically it is a faculty for inner representations':
one, we can seem to perceive when we are not in fact perceiving, and two,
we are able to do so by means of neural structures in our heads. 'These
representations are image-like': the experience of imagining is (in some
ways) like the experience of look at a picture. 'They share a certain character
with external images ... they represent absent objects as present': when
we imagine we merely seem to see. 'They do so by means of resemblance':
to the extent that the structure we are when we imagine is like the structure
we are when we perceive, we find the two experiences similar and respond
similarly within them.
Brann's classically mentalist description of imagining is not so much mistaken
as awkward, uninformative, and misleading. When we talk about inner images
that resemble objects we cannot help importing the structure of our dealings
with external images; thus we automatically think of ourselves as scanning
them, storing them, comparing them with the original they depict. We think
of them as located in their own space, which must be inner since it is not
outer. And we think of ourselves, when we 'see' them, as separate from them,
looking at them across a little distance. None of this do we intend to do:
it simply comes with using a picture metaphor for imagining. We are Cartesian
materialists not by intention but by metaphor.
If, along with thinking of every cognitive moment as a physical configuration
that we ARE and not as a 'representation' we somehow 'are aware of', we
keep in mind the fact that every theorist is such a configuration in the
moment of writing theory, we may be able to spot the simulational structure
that is misdistributing parts of what is not-wrong basic intuition. We could
apply brain theory to creating better brain theory, and we could be clearer
about the ways transitional theory IS transitional and needs to be teased
apart into its useful and nonuseful threads.
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