Motion Control and Consciousness
84 Marin Avenue
Sausalito, CA 94965, USA
tmongan@mail.com
Abstract.
This note suggests that
physical processes supporting the capabilities necessary for efficient
independent movement are sufficient to generate at least a rudimentary form of
consciousness.
Introduction
Most of us seem more inclined
to attribute consciousness to dogs than to rosebushes. This intuition indicates consciousness in an
entity may relate to its capacity for independent movement. Careful thinkers (Cotterill, 1996, 1997,
2000; Humphrey, 2000; Hurley, 1998; Llinas, 2001; Panksepp, 2001;
Sheets-Johnstone, 2001 and Tye, 1997) have come to similar conclusions. This note specifically argues that the
physical processes providing the capabilities necessary for an entity to
execute efficient independent movements are sufficient to generate at
least a rudimentary form of consciousness.
"Independently moving entities" are defined as entities that
can move from place to place by using coordinated movements of directly
connected and differentiated sub-components, under internal power and
direction, to obtain energy and avoid destruction. This definition excludes things like windblown seeds, waterborne
eggs, remote controlled entities, plants, schools of fish, flocks of birds,
colonies of unicellular organisms, ant colonies, or termite colonies (Humphrey
and Dennett, 1989).
Motion control system requirements
From an engineering
standpoint, successful control of actions of independently moving entities in a
dynamic environment requires:
·
Internal motion
control. An independently moving entity must have a
self-contained internal motion control system.
The motion control system must be capable of choosing just one movement
sequence out of the many possible movement sequences in any given situation.
·
Sensing. Sensing
is necessary to tell the motion control system about the entity's internal
conditions, and environmental conditions affecting the survival of the
entity. Sensing systems provide
information needed for the motion control system to decide whether the entity
should move and, if so, how and where.
Sensory inputs identifying internal conditions must be separated from
sensory inputs identifying external conditions. This enables the entity to move by acting on its surroundings.
·
Memory. Some
type of time-ordered memory of internal and external events is needed, so the
entity need not repeatedly re-invent previously useful motion sequences in
recurring situations.
Regardless of the details of
the physical processes providing these capabilities, they seem sufficient to
generate consciousness in independently moving entities, in the sense described
below.
Aspects of consciousness
Cotterill (1997) says
"the dictionary consensus…defines consciousness as an awareness of the
surrounding world, of the self, and of one's thoughts and feelings." A distinction is often made between first
person and third person aspects of consciousness (Block, 1995; Chalmers, 1995;
Nagel, 1974; Tye, 1997). Third person
descriptions of consciousness are of the form "A conscious entity does
this and that," and first person descriptions are of the form "I
experience this and that."
Dennett (1995) says we should
consider "what entities…can do" to decide whether those
entities "are conscious, and if so, why, and of what." However, Chalmers (1995) calls such
externally detectable third person aspects of consciousness the "easy
problems of consciousness", and includes among them such things as
·
"the ability to
discriminate, categorize, and react to environmental stimuli;
·
the integration of
information by a cognitive system;
·
the reportability of
mental states;
·
the ability of a system
to access its own internal states;
·
the focus of attention;
·
the deliberate control
of behavior;
·
the difference between
wakefulness and sleep."
First person aspects of
consciousness involve the arguably more difficult problem of explaining the
phenomena of experience (qualia). Tye
(1997) defines qualia as "the introspectively accessible phenomenal
aspects of mental life." Chalmers
(1995) claims "an organism is conscious if there is something it is like
to be that organism", and identifies the "hard problem of
consciousness" as that of explaining the first person phenomena of
experience (qualia). Two questions must
be addressed: "What are qualia?" and "Why do qualia occur?"
There is a fundamental
disagreement in the study of consciousness between those who think first person
consciousness can be explained directly in terms of physical processes and
those who think something else will be needed.
The first group includes Dennett (1996), who claims an explanation of
the "easy" problems of consciousness will also explain the "hard
problem." The second group
includes Chalmers (1995), who says
For any physical process we
specify there will be an unanswered question: Why should this process give rise
to experience? Given any such process,
it is conceptually coherent that it could be instantiated in the absence of
experience. It follows that no mere
account of the physical process will tell us why experience arises.
So, the explanation of first
person consciousness set forth below is unlikely to satisfy the second group.
Consciousness from motion control
A motion control system with
the previously listed capabilities enables an entity to
·
distinguish itself from
its surroundings, and
·
use its historical
record of its internal status, environmental conditions, and its actions in the
environment
to select and execute
movement sequences that may increase its chances of survival. In so doing, such entities necessarily
discriminate, categorize, and react to environmental stimuli; integrate
information; access their internal states; focus attention; and control their
own behavior (Chalmers, 1995). An
independently moving entity's internal historical record can provide "the
'story line' known as the stream of consciousness" (Cotterill, 1997). The entity's history of choices of specific
sets of movements provides at least the illusion of free will (Aleksander,
1998). Entities that move from place to
place to acquire energy and avoid destruction "behave as if they
had intentionality" [Dennett, 1994].
In other words, such independently moving entities act as if they had
"ideas" or "beliefs" about things useful to them and
places to be avoided. So, it seems
third person aspects of consciousness can be explained in terms of the
structure and function of the motion control systems in independently moving
entities.
It remains to relate motion
control to first person aspects of consciousness involving "qualia"
or "experience." The
connection can be made by identifying experience with the continually shifting
pattern of activity in the motion control system of an independently moving entity
in a changing environment. The
experience consisting of this changing pattern of motion control system
activity is unique to (and only fully accessible by) that entity. If qualia are the time varying patterns of
motion control system activity, they occur because they necessarily result from
the action of the motion control system.
In this reductionist view,
"what it is like to be a bat" (Nagel, 1974) is what it is like to
have the motion control system of a particular bat, accessing the internal
self-reports of shifting sensory inputs
and motion control system activation in that bat's brain as it moves in a
specific environmental situation. For
effective motion control, the bat must make "judgements (of some
inarticulate sort) in order to organize and modulate its language-free
activities. Wherever these inarticulate
judgement-like things happen is where we should look for the bat's privileged
vantage point" (Dennett, 1995).
Qualia are essentially
private because any attempt to observe the instantaneous status of an entity's
motion control system activity from the outside will significantly modify that
activity. In addition, the nature of
the independently moving entity affects the nature of the qualia. A man would have to be an exact replica of
his sister to know exactly what it is like to be that sister. Nevertheless, there is something it is like
to be the man's sister, even if he cannot know exactly what it is.
The identification of
experience with activity patterns in the motion control system of an entity
with directly connected components implies there is nothing "it is
like" to be a brick, a rosebush, a flock of birds, a school of fish, or a
termite colony. However, there is something
"it is like" to be an individual bird, a bat or a cockroach. Entities with simple motion control systems
would be expected to have simple experiences and entities like your brother or
sister, with elaborate motion control systems, would be expected to have rich
and elaborate experiences.
The short-term working memory
needed to execute movement sequences may engender the brief time span of
present consciousness (Humphrey, 2000).
This is consistent with the idea that "…the memory process directly
involved in consciousness is of the very short…type which lasts a few seconds
at most." (Cotterill, 1996).
Motion control system
activation can be expected to be particularly intense in situations of great
importance to an entity's survival.
High activation of an entity's motion control system would correspond to
particularly vivid qualia (experiences).
Retaining memories of sensory inputs, motion control system activation,
movement options and choices, and the resulting consequences in important situations
confers a competitive advantage. So,
vivid qualia might be associated with enhanced memory retention in situations
where those memories could be particularly relevant to future situations.
Identifying qualia as the
instantaneous status of motion control system activation is consistent with
Dennett's (1996) position that an explanation of the "easy" problems
of consciousness will explain the "hard problem." The idea that qualia, or a sense of
experience, will arise in any independently moving entity is also consistent
with Chalmers' (1995) "principle of organizational invariance." Chalmers' principle says "what matters
for the emergence of experience is not the specific physical makeup of a
system, but the abstract pattern of causal interaction between its
components."
The dynamic view of qualia
set forth above can be contrasted with Llinas' (2001) proposal that qualia can
be identified with fixed action patterns in the sensory systems.
Ramifications
Suppose some moving entities
are self-reproducing and evolve under selective pressure over millions of
years. Then one might expect motion
control system capabilities in some of these entities to become increasingly
elaborate. We see the results of such
selection here on earth, where Berthoz (2000) says "The brain is above all
a biological machine for moving quickly while anticipating."
Some elaborated motion
control system capabilities may result from "principles of good
design…homed in on by self-designing systems" (Dennett, 1986) under
selective pressure. Possible
consequences for the consciousness of entities with more advanced motion
control capabilities include the following:
·
In dynamic environments,
sources of energy or danger may not be stationary. Berthoz (2000) claims nearly
all sensory receptors detect the derivatives of the variables that activate
them, and says "Evolution obviously selected receptors capable of
predicting the future." Entities
with motion control systems that can predict movements of external objects and
the consequences of the entity's own movements have a selective advantage
(Dennett, 1984). A capability for predicting consequences of remembered
movement sequences in alternative situations also provides a selective
advantage (Llinas, 2001), and could be the beginning of thinking.
·
Some entities might develop
motion control systems with multiple motion control circuits, each suited for
specific movement sequences useful in different situations. The dominant motion control circuits in any
given situation should be those relevant to the highest levels of threat or
reward in the environment. Other
aspects of motion control (e.g., respiration, locomotion and circulation in
animals) could be automatically accomplished in the background (Llinas, 2001). This directs energy to the most important
problems at the moment, resulting in a shifting focus of attention. Activation of different motion control
circuits, appropriate to different conditions, will change the entity's
response characteristics in different situations. This is analogous to our sense that we are different persons in
different circumstances.
·
Recognizing that other
moving entities might make choices, and successfully estimating what those
choices might be in novel situations, provides a competitive advantage. Motion control systems with this capability
are essentially recognizing the existence of "other minds."
·
Entities that react
appropriately to harm done to similar entities nearby, or increased activity of
other entities in the presence of energy sources, will have a competitive advantage. This could lead to something analogous to
empathetic behavior.
·
Motion control is a
demanding task. If the motion control
system is also responsible for internal movements related to housekeeping and
maintenance activities, some entities may develop the capacity to periodically
shut down motion control circuits used to direct movement from place to
place. This "sleeping" allows
energy otherwise required for motion control to be devoted to internal housekeeping
and maintenance chores. Sleeping would
be most likely to occur when the entity is safe from external danger and has
adequate stores of energy.
·
An efficient motion
control system must monitor the overall status of all of the moving entity's
systems. Motion control circuits
activated in a crisis can be more efficient if they only monitor the most
critical system status indicators. That
is, efficiency will improve if the motion control system responds primarily to
the highest excitations of the sensory systems, focusing its attention in a crisis. Under benign conditions, a motion control
system will receive a wide array of sensory inputs in an unstressed state. It can then evaluate, at leisure, a range of
alternative motion strategies of potential adaptive value. Evaluation of alternate motion strategies in
response to fluctuating sensory inputs in an unstressed system would result in
randomly shifting conscious attention in unstressed conditions.
Relation to human consciousness
There is no need to assume a
homunculus in a Cartesian theater within ourselves. Our motion control systems access a unique historical record of
sensory inputs, movement alternatives evaluated, expected consequences of
movement alternatives, movement sequences selected, and the consequences of
actual movement sequences executed in the past. The record involves abstract metaphorical movements (such as
those considered by lakoff in connection with language and thought) and seems
to be the source of our sense of personal unity. A functioning motion control system accessing a historical record
of sensory inputs and movement alternatives, choices and consequences is a
reasonable candidate as the basis for our sense of self, because it is "a
framework that remains largely stable across many different life situations"
(Baars, 1996). This is "consistent
with the neurological evidence that no particular cortical lesion abolishes the
sense of 'self'" (Calvin, 1996).
In this view, one would not expect the sense of self to be abolished
unless all brain tissue necessary for independent movement were destroyed.
The idea that our motion
control systems are the basis of consciousness certainly does not deny
consciousness and a sense of self to persons paralyzed from birth. Such individuals have the same basic brain
structure as people capable of a full range of movement. Their observation and memory of the
movements of people and objects around them, and the consequences of those
movements, should give them a consciousness and sense of self similar to people
who are not paralyzed.
Each hemisphere of the human
brain controls movements of the opposite side of the body. Severing the corpus callosum connecting the
two hemispheres does not prevent coordinated movement on either side of the
body, but may result in conflicting motions by the right and left side of the
body. In "split-brain patients,
where transfer of information between the two hemispheres is blocked, the left
side can be shown to maintain a narrative account of its reality that can be
quite different from the right side's story" (Baars, 1996). The hypothesis that consciousness is an
outgrowth of the capabilities of independent motion control systems explains
the twin consciousness in split brain patients, without the need to consider
the neurological details invoked by Cotterill (1996).
Readiness potentials are
electrical changes in the brain preceding human actions. These potentials can be detected before a
person consciously decides to act (Libet et al., 1983). This is congruent with the idea that
consciousness relates to motion control system activities. Although we may act freely, the part of us
that actually initiates action may not be the conscious entity we
perceive. We may decide to act
subconsciously, with our consciousness only becoming aware of the decision
later, when the decision is recorded in the short-term working memory needed to
maintain movement sequences.
In self-reproducing entities
that mate repeatedly, there is high motion control system activation in
situations involving sex. This can lead
to particularly vivid and attractive qualia.
Sexually reproducing entities whose motion control circuits lead them to
repeatedly seek sex and the associated rewarding experiences have a competitive
advantage. This is one reason why
population control will not be easy.
Most of us are well aware of
the human capability for dissatisfaction, even in near ideal
circumstances. The relation between
motion control and consciousness might cast light on this unfortunate, but
perhaps inescapable, capability. Soren
Kierkegaard is reported to have said that comparison is the root of all
unhappiness. However, independently
moving entities use comparison as the basis of their survival strategy. Their motion control systems must
continually evaluate whether or not the entity would be better off somewhere
else. Shutting down this comparison
capability would eliminate the advantages of movement. Even in the best circumstances, our motion
control systems continually and restlessly compare the advantages of our present
situation with the possible advantages of alternative situations we might reach
by some movement sequence. So, perhaps
our capacity for dissatisfaction is partially rooted in the survival strategies
of moving entities.
References