13 June 2005
TOWARD
A HIGH-LEVEL DEFINITION OF
CONSCIOUSNESS
Manuel Blum
Ryan Williams
Brendan Juba
Matt Humphrey
From Collins
English Dictionary, 1995:
conscious adj.
• 4. a. denoting or relating to a part of the
human mind that is aware of a person’s
self, environment, and mental activity and
that to a certain extent determines his
choices of action.
•
b. (as n.) the conscious is only a small
part of the mind. Compare unconscious.
My credentials for studying
consciousness:
•
-
My credentials for studying
consciousness:
- 3rd grade, Bernard Blum (Dad) - brains
- Richard Schoenwald - Freud
- In the Neurophysiology Lab of
Dr. Warren S. McCulloch and
Walter Pitts – A Logical Calculus
- Hartley Rogers - Recursion Theory
- Marvin Minsky (PhD advisor) - AI
- When I got tenure, …
A complete summary of
my results:
• Consciousness is a kind of flashlight. The
flashlight beam is a limited resource (what
Minsky calls a serial bottleneck)
• Our conscious self is offered a set of choices.
The beam of consciousness selects one. This
repeats ad infinitum
Applications
Philosophy
• Understanding “understanding,” “selfawareness,” “free will,” resolving:
“All theory is against the freedom of the will;
all experience for it.” — Dr. Johnson
Science
• Building good theorem provers (as opposed
to proof checkers), and better CAPTCHAs
Why Consciousness Now
• There are many researchers trying to
understand consciousness, including
– Philosophers: since forever
– Neurophysiologists: fMRI studies!
– Cognitive psychologists
– Roboticists
• No complexity theorists that I know of
– Les Valiant comes closest
– Leslie Lamport “How to Write a Proof”
Why should Complexity Theorists
study Consciousness?
• They have not thought about it, but they
are well-suited to develop the theory
– Automata and Turing machines
– Knowledge (Zero-knowledge)
– Randomness (Pseudorandomness)
– They understand that complexity rulez
• Researchers in The Scientific Study of
Consciousness cry out for a theory
Our approach is to define a formal
concept of consciousness, called
CONSCSness
• CONSCS = Conceptualizing Strategizing
Control Systems
• CONSCSness = the state, condition, or
quality of being CONSCS
Informal Notion of Entity &
Environment
• An ENTITY is an organism (such as an ant
or a person) or an organization (such as
an ant colony, a cultural group, or a nation)
— in relation to an environment
• An entity's ENVIRONMENT at time t is the
entity's (relevant) world at time t: the
context in which the entity functions
More Formal Definition of
Environment & Entity
• An ENVIRONMENT is a computational
device having the full power of a Universal
Turing Machine (UTM). It is connected to a
collection of other computational devices,
called ENTITIES
• An ENTITY is a computational device that
(together with memory supplied by the
environment) has the full power of a UTM
You have just seen the only
“definitions” in this talk…
…unfortunately
The CONSCS-defining game
1. Formal definition of CONSCS should be
mechanically applicable to any entity in a
well-defined environment
– One should not have to be conscious to test if
an entity is a CONSCS
– This requirement has a similar (but weak)
analogy with CAPTCHAs, which are bots that
distinguish humans from bots
– We do NOT require that our definition of
consciousness be “black-box.” One may be
forced to “open up” an entity
The CONSCS-defining game
1. Formal definition of CONSCS should
be mechanically applicable to any
entity in a well-defined environment
2. The question whether an entity is CONSCS is a
function of its algorithms, not the stuff (silicon
or carbon) that implements those algorithms
3. In the real-world environment, people are CONSCS
while rocks are not (CONSCS)
Informally: An entity is CONSCS
relative to a given environment iff:
1. The entity has a model of its environment, and a
model of itself in the environment
2. The entity is motivated/driven towards goals
3. The entity is able to “try on any 'story' for size.”
Story provides strategy for dealing with the world
4. The entity has simple serial circuit — the CONSCS
processor — as interface between self and world
1. The entity has a model of
its environment and a model
of itself in its environment
Entity
Model
of
Entity
Model of
Environment
Environment
1. The entity has a model of its
environment and a model of
itself in its environment
A. These models are for making predictions
B. The models are derived from experiment
C. The models are constantly being revised
• A, B, C are done unconsciously/automatically.
• Revisions C are called TACTICAL revisions.
2. The entity is designed to
achieve certain goals
.
• Goals are determined by the values of two real variables,
“pleasure” and “pain,” and a “current story (CS).”
• Options for conscious consideration (evaluation by below
formula) bubble up to consciousness.
• The entity is designed to consider each such option and
select the option that maximizes
net payoff under CS (current story) =
Expected
prob distribs
inherent in models
of environ and self


[ pleasurecs(t) – paincs (t) ] dt
t0 = current time
Options bubble up
• Options are generated by systems of the
(parallel) unconscious brain, which present
their few best ideas to consciousness.
• Options presented to consciousness are
considered for a vote by the entire brain*.
– the entity uses its current story/strategy to
decide which option to select
* a vote taken by the entire brain accounts for
the (apparently) serial bottleneck.
Two kinds of options
bubble up from the unconscious:
Some are stories/strategies, such as:
I am a scientist
or
I am a crook.
Some are not stories, including:
Get a glass of water
Go for a swim
or
or
Get a cup of coffee.
Write up your results.
3. The entity has the ability to
“try on ANY ‘story’ for size”
A story is a theory about the world, such as:
.
Other entities are built just like me
Other entities are mindless robots
A story suggests a strategy* for dealing with the world:
Treat other entities with respect
Treat other entities any way you like
ANY ‘story’ means any story/strategy that any entity
could use to make decisions
We are not claiming that any story will or even could come up,
only that if it came up it would be considered.
models/tactics
vs
stories/strategies
• Models are updated unconsciously. We
call these tactical updates.
• Stories are updated consciously. We call
these strategic updates.
4. The entity has a simple serial
circuit — the CONSCS processor —
as interface between
Entity’s internal unconscious (parallel) brain
AND
Entity’s external (massively parallel) world
• CONSCS processor is for choosing a story, and
using story to select strategic option to focus on
• The options are offered up by the entity’s
internal (unconscious parallel) brain
• Choice made according to current story/strategy
What humans are conscious
of: all options that bubble up to the CONSCS processor
(but not lesser options that don’t rise to that level).
This includes:
• inputs from the external environment,
• inputs from the internal environment,
• actions that one can perform on the two
environments.
• pleasure and pain: current values.
Applications
Philosophy
• Understanding “understanding,” “selfawareness,” “free will,” resolving:
“All theory is against the freedom of the will;
all experience for it.” — Dr. Johnson
Science
• Building good theorem provers (as opposed
to proof checkers), and better CAPTCHAs
Bibliography on the Scientific
Study of Consciousness
• David Chalmers, philosopher logician, has a huge
excellent online bibliography
• Rodolfo Llinas, neuroscientist, is finding “Neural
Correlates of Consciousness”
• Bernard Baars has a long history of good writing;
his theater metaphor is widely accepted
• Daniel Dennett, Antonio Damasi, …
• Marvin Minsky never uses “consciousness” in his
“emotion machine,” as it means different things to
different people.