Copyright © 2002 Cycorp A Bundle of Assertions Think of a microtheory (mt) as a set of assertions. Each microtheory bundles assertions based on –a shared set of assumptions on which the truth of the assertions depends, or –a shared topic (world geography, brain tumors, pro football), or –a shared source: (CIA World Fact Book 1997, FM101-5, USA Today) the Cyc KB, as a sea of assertions

Copyright © 2002 Cycorp Avoiding Inconsistencies The assertions within a microtheory must be mutually consistent –no monotonic contradictions allowed within a single microtheory Assertions in different microtheories may be inconsistent the Cyc KB, as a sea of assertions in MT1: tables, etc., are solid in MT2: tables are mostly space in MT1: Mandela is an elder statesman in MT2: Mandela is President of South Africa in MT3: Mandela is a political prisoner

Copyright © 2002 Cycorp Every Assertion is in a Microtheory Every assertion falls within at least one microtheory Currently, every microtheory is a reified (named) term, such as #$HumanActivitiesMt or #$OrganizationMt Mts are one way of indexing all the assertions in Cyc

Copyright © 2002 Cycorp Better/faster/more scalable knowledge base building Better/faster/more scalable inferencing, too. To focus development of the Cyc knowledge base To enable shorter and simpler assertions Mandela is president vs. Mandela is president throughout 1995 in South Africa Tables are solid vs. At granularity usually considered by humans, tables are solid To cope with global inconsistency in the KB, inevitable at this scale Each mt is locally consistent (content in unrelated mts is not visible) Good for handling divergence (different points of view, scientific theories, changes over time) Why Have Microtheories?

Copyright © 2002 Cycorp Better/faster/more scalable knowledge base building Better/faster/more scalable inferencing, too. To focus development of the Cyc knowledge base To enable shorter and simpler assertions Mandela is president vs. Mandela is president throughout 1995 in South Africa Tables are solid vs. At granularity usually considered by humans, tables are solid To cope with global inconsistency in the KB, inevitable at this scale Each mt is locally consistent (content in unrelated mts is not visible) Good for handling divergence (different points of view, scientific theories, changes over time) Why Have microtheories? (cont.)

Copyright © 2002 Cycorp #$VocabularyMicrotheory -- each instance contains definitions of general concepts used in a knowledge domain (e.g., #$TransportationVocabMt, #$ComputerSoftwareVocabMt) #$TheoryMicrotheory -- each instance contains general assertions in a knowledge domain (e.g., #$TransportationMt,#$ComputerSoftwareMt). #$DataMicrotheory -- each instance contains assertions about specific individuals (e.g., #$TransportationDataMt, #$ComputerSoftwareDataMt) Some types of microtheories #$Microtheory #$TheoryMicrotheory #$DataMicrotheory #$CounterfactualContext #$PropositionalInformationThing genls #$VocabularyMicrotheory genls

Copyright © 2002 Cycorp Some types of microtheories #$Microtheory #$TheoryMicrotheory #$DataMicrotheory #$CounterfactualContext #$PropositionalInformationThing genls #$VocabularyMicrotheory genls #$PropositionalInformationThing --each instance of this collection contains assertions representing the propositional content of some #$InformationBearingThing (such as a picture, text, or database table). #$CounterfactualContext -- each instance of this collection contains at least one assertion which is not generally taken to be true in the real world (e.g., #$TheSimpsonsMt, #$SQ77bMt)

Copyright © 2002 Cycorp Explicitly relates a microtheory to a formula that is true in that microtheory. (#$ist MT FORMLA) means that the Cyc formula FORMLA is true in the microtheory MT. Microtheory predicates: #$ist (#$ist #$CyclistsMt (#$isa #$Lenat #$Person)) (#$ist #$NaiveStateChangeMt (#$implies (#$and (#$isa ?FREEZE #$Freezing) (#$outputsCreated ?FREEZE ?OBJ)) (#$stateOfMatter ?OBJ #$SolidStateOfMatter)))

Copyright © 2002 Cycorp Relates two microtheories such that one of them inherits the assertions in the other; i.e., the first microtheory has access to the assertions in the second microtheory. (#$genlMt MT-1 MT-2) means that every assertion which is true in MT-2 is also true in MT-1. #$genlMt is transitive. Microtheory predicates: #$genlMt (#$genlMt #$TransportationMt #$NaivePhysicsMt) (#$genlMt #$ModernMilitaryTacticsMt #$ModernMilitaryVehiclesMt) (#$genlMt #$EconomyMt #$TransportationMt)

Copyright © 2002 Cycorp #$genlMt Microtheory predicates, cont’d. #$BaseKB #$NaiveSpatialMt #$NaivePhysicsMt#$NaturalGeographyMt genlMt #$MovementMt genlMt #$TransportationMt genlMt

Copyright © 2002 Cycorp #$Predicate A sentence built from a predicate is either True or False. (#$mother #$ChelseaClinton #$HillaryClinton) is True (#$physicalParts #$TheWhiteHouse #$TheLincolnMemorial) is False Predicates are thus truth-functional relations.

Copyright © 2002 Cycorp Argument Types Example 1 (#$arg1Isa #$mother #$Animal) (#$arg2Isa #$mother #$FemaleAnimal) Thus, (#$mother #$ChelseaClinton #$HillaryClinton) is a well-formed sentence because : (#$isa #$ChelseaClinton #$Animal) and (#$isa #$HillaryClinton #$FemaleAnimal)

Copyright © 2002 Cycorp Second-Order Predicates Sometimes we want to make statements about predicates themselves. This requires “second-order” predicates, which can take predicates as arguments. Examples : #$arg1Isa, #$arity, #$isa Thus in (#$arity #$mother 2), #$arity takes the predicate #$mother as its first argument. Some second-order predicates are used to relate CycL predicates to one another within a predicate hierarchy...

Copyright © 2002 Cycorp The Form and Content Of The Knowledge Base The main advantage of Cyc over other systems for representing knowledge is its use of a formal language in which inferential connections between concepts and statements are encoded in a machine accessible way. The content of the Knowledge Base comprises: –A vast taxonomy of concepts and relations –A rich formal representation of their interconnections

Copyright © 2002 Cycorp Arrangement, by Generality Facts (Database) Upper Ontology Core Theories Domain-Specific Theories Upper Ontology: Abstract Concepts Core Theories: Space, Time, Causality, … Domain-Specific Theories Facts: Instances Knowledge Base Layers

Copyright © 2002 Cycorp Arrangement, by Generality Facts (Database) Upper Ontology Core Theories Domain-Specific Theories EVENT  TEMPORAL-THING  INDIVIDUAL  THING Upper Ontology: Abstract Concepts Knowledge Base Layers

Copyright © 2002 Cycorp Arrangement, by Generality Facts (Database) Upper Ontology Core Theories Domain-Specific Theories EVENT  TEMPORAL-THING  INDIVIDUAL  THING For all events a and b, a causes b implies a precedes b Upper Ontology: Abstract Concepts Core Theories: Space, Time, Causality, … Knowledge Base Layers

Copyright © 2002 Cycorp Arrangement, by Generality Facts (Database) Upper Ontology Core Theories Domain-Specific Theories EVENT  TEMPORAL-THING  INDIVIDUAL  THING For all events a and b, a causes b implies a precedes b For any mammal m and any anthrax bacteria a, m’s being exposed to a causes m to be infected by a. Upper Ontology: Abstract Concepts Core Theories: Space, Time, Causality, … Domain-Specific Theories Knowledge Base Layers

Copyright © 2002 Cycorp Facts (Database) Upper Ontology Core Theories Domain-Specific Theories EVENT  TEMPORAL-THING  INDIVIDUAL  THING For all events a and b, a causes b implies a precedes b For any mammal m and any anthrax bacteria a, m’s being exposed to a causes m to be infected by a. John is a person infected by anthrax. Upper Ontology: Abstract Concepts Core Theories: Space, Time, Causality, … Domain-Specific Theories Facts: Instances Knowledge Base Layers Arrangement, by Generality

Copyright © 2002 Cycorp #$Thing #$Intangible #$ Individual #$SetOrCollection #$TemporalThing #$SpatialThing-Localized #$ExistingStuffType #$ExistingObjectType #$Event #$PartiallyTangible #$Collection #$genls #$typeGenls #$disjointWith Some Top Level Collections

Copyright © 2002 Cycorp #$Dog (the collection of all dogs) #$isa: #$OrganismClassificationType #$BiologicalTaxon #$BiologicalSpecies #$DomesticatedAnimalType #$genls: #$CanineAnimal

Copyright © 2002 Cycorp 45 Collections of which #$Dog” is a Specialization Agent Agent-Generic AirBreathingVertebrate Animal AnimalBLO BilateralObject BiologicalLivingObject CanineAnimal Carnivore CarnivoreOrder ChordataPhylum Coelomates Container- Underspecified Dog EukaryoticOrganism Eutheria FrontAndBackSidedObject Heterotroph HexalateralObject Homeotherm HumanScaleObject Individual IndividualAgent LeftAndRightSidedObject Location-Underspecified Mammal NaturalTangibleStuff NonPersonAnimal OrganicStuff Organism- Whole PartiallyTangible PerceptualAgent Region-Underspecified SentientAnimal SolidTangibleThing SomethingExisting SpatialThing SpatialThing-Localized System-Generic TemporalThing TerrestrialOrganism Thing TopAndBottomSidedObject Trajector-Underspecified Vertebrate

Copyright © 2002 Cycorp 11 Collections of which #$Dog is an Instance #$OrganismClassificationType #$ConventionalClassificationType #$ExistingObjectType #$TemporalStuffType #$ObjectType #$Collection #$SetOrCollection #$MathematicalThing #$MathematicalOrComputationalThing #$Intangible #$PartiallyIntangible #$Thing

Copyright © 2002 Cycorp Relations Between Temporal Things – #$temporalBoundsIntersect – #$temporallyIntersects – #$startsAfterStartingOf – #$endsAfterStartingOf – #$endsAfterEndingOf – #$startingDate – #$temporallyContains – #$temporallyCooriginating – #$temporalBoundsContain – #$temporalBoundsIdentical – #$startsDuring – #$overlapsStart – #$startingPoint – #$simultaneousWith – #$after

Copyright © 2002 Cycorp Spatial Properties and Relations Surfaces, Portals and Cavities Shape Attributes (63) Types of Spatial Symmetry Direction and Orientation Vocabulary Relative Positions of Objects Nearness and Location Being Between ‘In-’ Predicates (~ 60) Connections Predicates (~ 65) Mereological Relations

Copyright © 2002 Cycorp Senses of ‘In’ Does part of the inner object stick out of the container? –None of it. -- Try #$in-ContCompletely –Yes -- Try #$in-ContPartially If the container were turned around could the contained object fall out? –Yes -- Try #$in-ContOpen –No -- Try #$in-ContClosed

Copyright © 2002 Cycorp Senses of ‘In’ Is it attached to the inside of the outer object? –Yes -- Try #$connectedToInside Can it be removed, if enough force is used, without damaging either object? –Yes -- Try #$in-Snugly or #$screwedIn Does the inner object stick into the outer object? –Yes -- Try #$sticksInto

Copyright © 2002 Cycorp Senses of ‘Part’ –#$parts –#$intangibleParts –#$subInformation –#$subEvents –#$physicalDecompositions –#$physicalPortions –#$physicalParts – #$externalParts –#$internalParts –#$anatomicalParts –#$constituents –#$ingredients

Copyright © 2002 Cycorp Some Events Types #$PhysicalStateChangeEvent #$TemperatureChangingProcess #$BiologicalDevelopmentEvent #$ChangingDeviceState #$CuttingNails #$Cracking #$Carving #$ShapeChangeEvent #$MovementEvent #$GivingSomething #$DiscoveryEvent #$Buying #$Thinking #$Baking #$Singing #$PumpingFluid

Copyright © 2002 Cycorp Roles and ActorSlots (the world’s largest collection) Agency or initiating an event Objects acted on or changed Objects created or destroyed Facilitating objects or stuff in an event Slots of motion and location Instruments Beneficiary/maleficiary Specialized actor roles, like #$plaintiffs

Copyright © 2002 Cycorp Roles and ActorSlots “Moe clobbered Curly with the British scepter.”

Copyright © 2002 Cycorp Roles and ActorSlots “Moe clobbered Curly with the British scepter.” Relations between an event and its participants Cyc has over 200 role and ActorSlot predicates Clobbering14 #$performedBy CurlyTheUKScepter Moe #$victim #$deviceUsed

Copyright © 2002 Cycorp This represents a particular clobbering event, not clobberings in general. Clobbering14 performedBy CurlyTheUKScepter Moe victims instruments Roles and ActorSlots “Moe clobbered Curly with the British scepter.”

Copyright © 2002 Cycorp Roles in events and subevents A product of one subevent of the Krebs Process is the input to another. Hence, different ActorSlot predicates. SubProcessBSubProcessA #$inputsDestroyed #$outputsCreated Krebs Process

Copyright © 2002 Cycorp Information Information-Bearing Things –Books, web-page copies, radio broadcasts, utterances Abstract strings, characters Propositional Content Conceptual Works

Copyright © 2002 Cycorp What is “Moby Dick” ?

Copyright © 2002 Cycorp “ ‘ T i s M o b y D i c k ! ” (#$thereExists ?SEE (#$and (#$isa ?SEE Seeing) (#$objectPerceived ?SEE #$MobyDick) (#$perceiver ?SEE #$CaptainAhab))) AbstractInformationStructure (AIS) PropositionalInformationThing (PIT) InformationBearingThing (IBT)

Copyright © 2002 Cycorp “ ‘ T i s M o b y D i c k ! ” (and (isa ?SEE Seeing) (objectPercieved ?SEE MobyDick) (perceiver ?SEE CaptainAhab)) PropositionalInformationThing (PIT) AbstractInformationStructure (AIS) InformationBearingThing (IBT)

Copyright © 2002 Cycorp “ ‘ T i s M o b y D i c k ! ” (and (isa ?SEE Seeing) (objectPercieved ?SEE MobyDick) (perceiver ?SEE CaptainAhab)) #$AbstractInformationStructure (AIS) #$Proposition and #$PropositionalInformationThing (PIT) #$InformationBearingThing (IBT) #$ConceptualWork (CW)

Copyright © 2002 Cycorp PropositionalInformationThing (PIT) InformationBearingThing (IBT) ConceptualWork (CW) AbstractInformationStructure (AIS)

Copyright © 2002 Cycorp PropositionalInformationThing (PIT) InformationBearingThing (IBT) ConceptualWork (CW) instantiationOfCW AbstractInformationStructure (AIS)

Copyright © 2002 Cycorp AbstractInformationStructure (AIS) PropositionalInformationThing (PIT) InformationBearingThing (IBT) ConceptualWork (CW) textOfIBT instantiationOfCW InfoStructureOfCW #$infoStructureRepresents ContainsInfo-Propositional-CW PITOfIBTFn

Copyright © 2002 Cycorp Emotion Feeling Attributes Types –#$Abhorrence –#$Adulation –#$Relaxed-Feeling –#$Gratitude –#$Anticipation-Feeling –Over 120 of these Relations Pertaining to emotions –#$contraryFeelings –#$feelsTowardsObject –#$appropriateEmotion –#$feelsTowardsPersonType –#$actionExpressesFeeling

Copyright © 2002 Cycorp Propositional Attitudes Relations Between Agents and Propositions #$goals #$intends #$desires #$hopes #$expects #$beliefs #$opinions #$knows #$rememberedProp #$perceivesThat #$seesThat #$tastesThat

Copyright © 2002 Cycorp Biology Organisms classified by: –Taxon –Habitat –Source of Nutrients Some scientific, #$ChordataPhylum, some not, #$Worm Organism Anatomy –Gross Anatomy –Cell biology –Physiological Processes Life stages

Copyright © 2002 Cycorp Materials Common Substances Attributes of Materials States Of Matter Solutions Electrical Conductivity Thermal Conductivity Structural Attributes Tangible Attributes

Copyright © 2002 Cycorp Devices Specializations Of #$PhysicalDevice Device States Device Actions Device Predicates Device Purposes

Copyright © 2002 Cycorp Food Food Types Edibility Preparing food Consuming food Hunger

Copyright © 2002 Cycorp Weather Weather Attributes –#$ClearWeather – (#$LowAmountFn #$Raininess) Weather Events –#$TornadoAsEvent –#$SnowProcess Weather Objects –#$CloudInSky –#$TornadoAsObject

Copyright © 2002 Cycorp Geography Geopolitical Entities Addresses Specific Ethnic and Language information Borders Districts, States, etc. Seas, islands, straits,etc.

Copyright © 2002 Cycorp Inference uses Deduction: Rules + Facts Deduction - rule  fact(s)  new fact (#$loves #$Hamlet #$Gertrude) “Rules” - general, variables (#$implies (#$mother ?PERSON ?MOTHER) (#$loves ?PERSON ?MOTHER)) “Facts” - specific, no variables (#$mother #$Hamlet #$Gertrude)

Copyright © 2002 Cycorp The Resolution Principle (#$and (#$knows #$Hamlet ?WHO) (#$loves #$Hamlet ?WHO)) (#$implies (#$mother ?PERSON ?MOTHER) (#$loves ?PERSON ?MOTHER)) QueryRule Resolution Principle : “Unify, Substitute, Merge”

Copyright © 2002 Cycorp The Resolution Principle: Unify (#$and (#$knows #$Hamlet ?WHO) (#$loves #$Hamlet ?WHO)) (#$implies (#$mother ?PERSON ?MOTHER) (#$loves ?PERSON ?MOTHER)) Resolution Principle : “Unify, Substitute, Merge” QueryRule Pivot Literals

Copyright © 2002 Cycorp (#$and (#$knows #$Hamlet ?WHO) (#$loves #$Hamlet ?WHO)) (#$implies (#$mother ?PERSON ?MOTHER) (#$loves ?PERSON ?MOTHER)) Most General Unifier #$Hamlet / ?PERSON ?WHO / ?MOTHER Resolution Principle : “Unify, Substitute, Merge” QueryRule The Resolution Principle: Unify (#$loves #$Hamlet ?WHO)) =

Copyright © 2002 Cycorp The Resolution Principle: Substitute (#$and (#$knows #$Hamlet ?WHO) (#$loves #$Hamlet ?WHO)) (#$implies (#$mother ?PERSON ?MOTHER) (#$loves ?PERSON ?MOTHER)) Most General Unifier #$Hamlet / ?PERSON ?WHO / ?MOTHER Resolution Principle : “Unify, Substitute, Merge” QueryRule (#$and (#$knows #$Hamlet ?WHO) (#$loves #$Hamlet ?WHO)) (#$implies (#$mother #$Hamlet ?WHO) (#$loves #$Hamlet ?WHO)) Substituted QuerySubstituted Rule

Copyright © 2002 Cycorp The Search Tree Query/root Possible Answers: Branches/ Child nodes “Who does Hamlet know and love?”

Copyright © 2002 Cycorp Justifying the Answers  Query  Goal!  Logical Deduction with the Most General Unifier

Copyright © 2002 Cycorp The Halting Problem millions of facts + tens of thousands of rules infinite possibilities

Copyright © 2002 Cycorp Depth-first Search Traversal Start here

Copyright © 2002 Cycorp Depth-first Search Traversal ?

Copyright © 2002 Cycorp Depth-first Search Traversal ? ?

Copyright © 2002 Cycorp Depth-first Search Traversal ? *? GOAL!

Copyright © 2002 Cycorp Depth-first Search Traversal ? ? *?

Copyright © 2002 Cycorp Depth-first: advantage and disadvantage + Algorithmically efficient - No end

Copyright © 2002 Cycorp Breadth-first Search: advantage and disadvantage 0-step 1-step 2-step n-step + Deal with simplest proofs first - Infinite fan-out is common

Copyright © 2002 Cycorp Cyc is Life in the Big City Searching in Cyc: ~100,000 constants ~1 million assertions

Copyright © 2002 Cycorp Inference is Resource-bounded Resource Bounds : –quit after NUMBER of answers –quit after TIME seconds –ignore any proof using more than BACKCHAIN rules –ignore any proof using more than DEPTH steps

Copyright © 2002 Cycorp Inference Uses Mts for Consistency WorldMythologyMt (genls Vampire IntelligentAgent) (isa LochNessMonster Reptile) MainstreamAmericanCultureMt (genls Vampire MythologicalThing) (isa LochNessMonster MythologicalThing) In the Mainstream AmericanCultureMt, Vampire is a kind of mythological thing. The Loch Ness Monster is a mythological thing. In the WorldMythologyMt, Vampire is a kind of intelligent agent. The Loch Ness Monster is a reptile.

Copyright © 2002 Cycorp Mts Inherit from More General Mts Using #$genlMt UniversalVocabularyMt MainstreamAmericanCultureMt UnitedStatesSocialLifeMt genlMt HumanActivitiesMt genlMt WorldMythologyMt

Copyright © 2002 Cycorp Inference is performed Within Mts UniversalVocabularyMt MainstreamAmericanCultureMt UnitedStatesSocialLifeMt genlMt HumanActivitiesMt genlMt WorldMythologyMt ASK in each Mt: (genls Vampire IntelligentAgent) Results in each Mt: True Not Proven