Transcript Advanced concepts

Evolution of
Complex Systems
Lecture 11: Advanced concepts
Peter Andras / Bruce Charlton
[email protected]
[email protected]
Objectives
Limits of expression of communications
 Simplification and expansion
 Structures and institutes
 Professional languages
 Selection and competition
 Interpenetration of systems
 Evolution

2
Continuation distributions
E.g., human language
 Formalism:

 symbol set , x communication
x  
P ( x | R ( x )) continuation distribution
R ( x ) set of references (other communications )
Temporal order : x  y , y  T ( x )
z  T ( y ), y  T ( x )  z  T ( x )
R( x )  T ( x )
3
Random events

Example: random spikes / spontaneous
spikes
P* ( x )  p* , x  simplifica tion
in general P* ( x | T ( x ))
4
Meaningless communications
Not following the rules
 E.g.,:

Random communications
 Zero likelihood communications

5
Limited length communications

How long can be a sequence / pattern of
referencing communications that does not
appear as random ?
xn , xn 1 ,, x1
n
P( xn ,, x1 | R( xn ), , R( x1 ))   P( xi | R( xi ))  p*
i 1
6
Expressivity of a system language
Richer symbol sets imply shorter reference
sequences
 Trade-off between symbol set richness and
the length of referentially interlinked
communication sequences

x   ( x ),
( x )  n
P ( x | R ( x ))  1  ( n  1) p
*
7
Simplification of languages – 1

E.g.,
Neurons: graded potentials / spikes
 Brain: diverse cortex structure / crystalline
cortex structure
 Language: rich culture / simple culture

8
Simplification of languages – 2

Smaller symbol sets
( x )  ( x ' )
P( x | R( x ))  P ( x ' | R( x ' ))
9
Expansion of the language
Longer possible sequences
 Increased informational contents – better
description of the system / environment

P( x | R( x ))  P( x ' | R( x ' ))
10
Memory and expansion
Memory facilitates expansion by
allowing direct reference to earlier
communications
 Direct reference increases the likelihood
of generating continuation
communications

11
Information subsystem and
expansion
Information subsystem = processing of
memories, generating new memories 
identity definition, checking and
enforcement communications
 Processing memories = combination of
memories  simpler referencing of
combinations of memories
  better self/environment description

12
Structure of communications
Grammar in human language
 Courtship behaviour rules in animals
 Structuring the brain

13
Structure
Restrictions on the communications
 Structure makes sharper the
continuation distribution, e.g., by
eliminating some possible continuations

14
Specialist communication
Follows restrictive structural rules
 E.g., science, legal communications

15
Expansion by specialist communications
The possible continuation
communications are reduced in number
 P(x|R(x)) increases
 Longer referential sequences are
possible  expansion of the
communication system

16
Structure and specialisation
Structure induces simplicity in
communications and may lead to the
emergence of specialist communications
 Specialist communications induce
expansion of the communications
system

17
Institutions – 1

E.g.,
Courtship, marriage
 Parliament, cerebellum, Golgi organelle

18
Institutions – 2
Institution: large set of coherent rules
imposing structure
 The structural rules imply the
constitution of a subsystem of the
communication system

19
Institutions – 3

By inducing a subsystem, institutions
lead to the expansion of the
communication system
20
Professional language
E.g., legal language
 Specialist language in the context of an
institution system

21
Professional institution systems
Professional language and institution
system
 E.g., subsystems of modern society

22
Language code – 1

E.g., legal system:

legal / illegal


common / statute / commercial / penal
Multilevel set of questions with few
possible answers that classify
communications
23
Language code – 2
Professional languages with institution
systems
 Multilevel simple answer questions that
classify the communications along the
defining rules of the institution system
 Language code  system identity

24
Binary code





Social sub-systems: professional institution
systems
Legal / illegal; power / no power; profit / no
profit
Binary code: the top level coding that defines
what communications are part of a
communication subsystem of the society
If a communication can be referenced in such
terms it fits into the subsystem
There are further levels for inner distinctions
25
Environment of systems
Environment: infinitely complex
 System: communications about itself –
complementary model of the
environment

26
System actions and perceptions
System: model of the environment
Communications: reference other
communications and provide reference for
further communications  maintain the
system
 Communications lead to changes in the
environment by changing the behaviour of
communication units
 Changes in the environment lead to changes
in the system communications providing the
basis for system perceptions


27
Predictive sustainability
The system is reproducible / sustainable if the
actions of it produce appropriate changes in
the environment to expand the system
 Also, if perceptions lead to such appropriate
actions
 In a sense the system’s description of the
environment allows good predictions about
the environment to reproduce and expand
the system  predictive sustainability

28
Competing systems
Systems in the environment
Each having predictions about the
environment using their actions and
perceptions
 Systems have different level of predictive
sustainability depending on the environment
 Systems with better predictive sustainability
attract communication units to produce
communications that are part of the system
easier than systems with less predictive
sustainability


29
Selection of systems
Systems in an environment
 Selection pressures: which system has
better predictive sustainability in the
environment
 Systems with better predictive
sustainability are selected by the
environment

30
Simplicity, memory, expansion, selection
Systems with memory can expand more than
systems without memory
 Systems that undergo simplification and
expansion can capture a larger part of the
environment
 Longer descriptions make better predictions
 Better predictions make more likely selection
by environment

31
Interacting systems
Communication units produce
communications that are part of
systems (more than one)
 System communications have effect on
communication units, these affect the
communications produced by
communication units in other
communication systems

32
The boundary of systems
Communication units are not part of systems
 Systems are made up by communications
between communication units
 Dense / rare communication density
boundary in the sense of referencing
 System communications may also reference
communications which are not part of the
system (these are part of other systems)

33
Changing system boundaries
The number of references to communications
of several systems may change
 In this way the communications may belong
more to one system than to other systems
 One system may dominate the
communications of a communication unit of
which communications were dominated
before by another system

34
Interpenetrating systems






Two systems using communications of an overlapping
set of communication units
System 1 communications influence communication
units inducing changes in System 2; it works in both
ways
System 2 communications reference sometimes
System 1 communications
Such references may follow System 1 referencing
rules (i.e., continuation distributions)
New continuation distributions may emerge in System
2
E.g., Politics and education
35
Dense communications
Dense cluster of communications
between communication units
 Dense cluster in sense of referencing =
system

36
Double contingency and systems
Referencing to other system communications
 Questioning the existence of the communication
cluster – the system – questioning the identity of the
system (e.g., immune system)
 This leads to the formation of rules and sharpening
of rules / continuation distributions
 Subsystems as institution systems emerge from a
grouping of structure rules when the identity of the
communication cluster is questioned  double
contingency

37
Interpenetration and emergence
of systems
Systems interpenetrating  modifying each
other’s communication continuation rules
 Communications referring to communications
of both systems, new communications refer
to these communications
 New dense referencing cluster may emerge
 Questioning the existence of the new cluster
leads to the expansion of the cluster and
formation of the specific rules / continuation
distributions of the new system  identity
definition for the new system

38
Examples
Biology and mathematics  theoretical
biology
 Neuroscience and pharmacology 
neuro-pharmacology
 Media and hospitals  health care PR

39
Evolution of systems – 1
Systems recreate and expand
themselves
 They interact with other systems

Changing their rules
 Changing their boundaries
 Changing their identity

40
Evolution of systems – 2
Systems develop structures
 The structures may organize into
institution subsystems by questioning
the identity of the subsystem
 This may lead to simplifications
 Simplification trigger expansion

41
Evolution of systems – 3
At the interface of systems new dense
communication clusters may emerge
 By questioning the identity (existence)
of the new clusters new systems
emerge

42
Evolution of systems – 4
Systems compete for communications
between communication units
 Systems describe / predict the environment
 Systems with better predictions have better
predictive sustainability, they are selected
under environmental selection pressures
(they more easily reproduce and expand than
other systems with less predictive
sustainability)

43
Evolution of systems – Summary
Systems recreate, expand and change
 New systems and subsystems emerge
 Systems compete and some are
selected under environmental selection
pressures

44
Summary – 1
Length of communication references
 Simplification and expansion
 Structures, institutes and sub-systems
 Professional languages and binary code
 Predictive sustainability and selection

45
Summary – 2
Changing system boundaries
 Interpenetration of systems
 Double contingency and the emergence
of systems
 Evolution of systems

46
Q&A – 1
1.
2.
3.
Is it true that simplification of the
communication symbol set leads to the
expansion of the communication system ?
Is it true that structures are restrictions
on the continuation distributions leading
to the sharpening of them ?
Is it true that institutions are rule sets,
which may organize into sub-systems ?
47
Q&A – 2
4. Is it true that a professional language is a
subset of a system language corresponding to
an institution system ?
5. Is it true that the language code defines which
communications are part of the specialist
language ?
6. Is it true that the political system is a
professional institution system of the society ?
48
Q&A – 3
7. Is it true that professional institution systems
of the society have a binary code ?
8. Is it true that system communications can be
viewed as predictions about the environment ?
9. Is it true that a system’s ability to reproduce
and expand in an environment depends on the
system’s predictive sustainability ?
10. Is it true that selection pressures favour
systems with richer symbol sets ?
49
Q&A – 4
11. Is it true that interpenetration means that
systems change their boundaries as a result
of the interaction between the systems ?
12. Is it true that new systems always emerge
at the interface of systems ?
13. Is it true that questioning the identity of a
referential communication cluster leads to the
formation of the corresponding
communication system ?
50