Evolution of Complex Systems

Evolution of Complex Systems Lecture 11: Advanced concepts Peter Andras / Bruce Charlton peter.andras@ncl.ac.uk bruce.charlton@ncl.ac.uk

Objectives • Limits of expression of communications • Simplification and expansion • Structures and institutes • Professional languages • Selection and competition • Interpenetration of systems • Evolution

Continuation distributions • E.g., human language • Formalism:

Random events • Example: random spikes / spontaneous spikes

Meaningless communications • Not following the rules • E.g.,: • Random communications • Zero likelihood communications

Limited length communications • How long can be a sequence / pattern of referencing communications that does not appear as random ?

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

Simplification of languages – 1 • E.g., • Neurons: graded potentials / spikes • Brain: diverse cortex structure / crystalline cortex structure • Language: rich culture / simple culture

Simplification of languages – 2 • Smaller symbol sets

Expansion of the language • Longer possible sequences • Increased informational contents – better description of the system / environment

Memory and expansion • Memory facilitates expansion by allowing direct reference to earlier communications • Direct reference increases the likelihood of generating continuation communications

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

Structure of communications • Grammar in human language • Courtship behaviour rules in animals • Structuring the brain

Structure • Restrictions on the communications • Structure makes sharper the continuation distribution, e.g., by eliminating some possible continuations

Specialist communication • Follows restrictive structural rules • E.g., science, legal communications

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

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

Institutions – 1 • E.g., • Courtship, marriage • Parliament, cerebellum, Golgi organelle

Institutions – 2 • Institution: large set of coherent rules imposing structure • The structural rules imply the constitution of a subsystem of the communication system

Institutions – 3 • By inducing a subsystem, institutions lead to the expansion of the communication system

Professional language • E.g., legal language • Specialist language in the context of an institution system

Professional institution systems • Professional language and institution system • E.g., subsystems of modern society

Language code – 1 • E.g., legal system: • legal / illegal • common / statute / commercial / penal • Multilevel set of questions with few possible answers that classify communications

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

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

Environment of systems • Environment: infinitely complex • System: communications about itself – complementary model of the environment

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

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

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

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

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

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

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)

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

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

Dense communications • Dense cluster of communications between communication units • Dense cluster in sense of referencing = system

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

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

Examples • Biology and mathematics  theoretical biology • Neuroscience and pharmacology  neuro-pharmacology • Media and hospitals  health care PR

Evolution of systems – 1 • Systems recreate and expand themselves • They interact with other systems • Changing their rules • Changing their boundaries • Changing their identity

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

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

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)

Evolution of systems – Summary • Systems recreate, expand and change • New systems and subsystems emerge • Systems compete and some are selected under environmental selection pressures

Summary – 1 • Length of communication references • Simplification and expansion • Structures, institutes and sub-systems • Professional languages and binary code • Predictive sustainability and selection

Summary – 2 • Changing system boundaries • Interpenetration of systems • Double contingency and the emergence of systems • Evolution of systems

Q&A – 1 • 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 ?

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 ?

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 ?

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 ?

Evolution of Complex Systems