Representing Dispositions Johannes Röhl/Ludger Jansen Universität Rostock DFG-Projekt Good Ontology Design 06.07.2018 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Dispositions and their relations Simplifying assumptions Overview Motivation – what are dispositions and why are they useful in biomedical ontology? Dispositions and their relations Simplifying assumptions Binary formal relations Principles for surefire dispositions Outlook 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Motivation: Dispositions are frequent in biology and medicine disposition terms in SNOMED CT (including „tendency“, propensity): Tendency to bleed, tendency to nausea and vomiting, propensity to adverse reaction to food drugs like aspirin have abilities to relieve pain, molecules have dispositions to undergo certain chemical reactions under certain circumstances etc. Generally: We have a vital interest in what could happen, e.g. to prevent something bad from happening by taking precautions 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Examples: fragility, solubility What are dispositions? A Disposition is a property that is linked to a realization, to a behavior an individual with that disposition will show under certain circumstances or as response to a certain stimulus (trigger). Examples: fragility, solubility x has Disposition D implies the counterfactual conditional: if x was under circumstances C, x would exhibit behavior R (the realization of the disposition). 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Dispositions, interactions and causality Dispositions provide a link between types of particulars (the bearers of the dispositions) and types of processes and interactions these particulars are involved in: „The dispositions of things are thus essentially linked to kinds of processes, and every manifestation of a disposition must exemplify some kind of process.“ (Ellis/Lierse: “Dispositional Essentialism”, in Australas. Journal of Philosophy 1994) 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Diseases as dispositions Goldfain, Smith, Cowell 2010: „Dispositions and the Infectious disease Ontology“ (following OGMS) disease as triple of distinct aspects <disorder, disposition, course of disease> disease is a disposition towards pathological processes disorder is the non-dispositional basis (structure of properties) course of disease is a realization of the disease (as disposition), a process 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Diseases as dispositions disease as triplet <disorder, dispositon, course of disease> disease is a disposition towards pathological processes Drugs/Treatments as „antidotes“ with dispositions that counteract the disease, so the pathological processes are not realized fully. Distinction allows various disease courses and symptoms to be realizations of one and the same disorder. Dormant or latent disease: patient carries infectious agents but shows no symptoms 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Dispositions in BFO (Basic Formal Ontology) BFO Category .... dependent continuant └ quality └ realizable entity └ function └ role └ disposition → Necessary relations: realization (process) bearer (indepedent continuant the disposition inheres in) 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Possible Relations of a disposition Additional conditions Ci trigger T (process) Probability P Disposition Realization process bearer x (material entity) x has disposition D for realization R with probability P under circumstances C and trigger (Stimulus) T. 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Dispositions and their relations x has disposition D for realization R with probability P under circumstances C and trigger (Stimulus) T. 6 relata! Independent continuant x Disposition D Realization R (process) Probability P Circumstances C Trigger T 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Dispositions and their relations Descriptions Logics can deal well with binary relations only Simplify! Independent continuant x Disposition D Realization R: process Probability P only „surefire dispositions“ Circumstances C too general, ontologically not clear Trigger T: process, initiation of change 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Dispositions and their relations Still to many relata as Description logics admits only binary relations Split up in several binary relations: x has_disposition d d has_realization r (only one type „single track disposition“) d has_trigger t (only one type „single trigger disposition“) 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Primitive relations Take following (token level) relations as established (OBO, Smith et al. 2005) x instance_of X between a particular and its classes (both for processes and continuants) p has_participant x between particular processes and particular continuants q inheres_in x between individual instances of dependent and independent continuants (cf. Schulz/Jansen 2009, 23) 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Relations I - has_disposition x has_disposition d := D d instance_of D  D is_a Disposition  d inheres_in x if a disposition is essential for a type of continuant (all aspirins have the disposition pain relief) it will hold between types: A has_disposition D := x: x instance_of A → y: y instance_of D  y inheres_in x Subrelation of has_property (Schulz/Jansen 2009) 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Relations II - has_bearer Inverse of x has_disposition d: d has_bearer x subrelation of inheres_in like any property every disposition instance needs a bearer, but they do not have to be of the same type. Different drugs are bearers of the same disposition pain-relieving. If a disposition inheres only in one type, define type relation: X has_bearer Y := x: x instance_of X → y: y instance_of Y  x inheres_in y 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Relations III - has_realization connection of a disposition instance with the process instance it is a disposition for, its realization. Generalization cannot exhibit the “all-some”-structure: “For all instances x of D there exists a process instance y of R such that x has realization y” is clearly wrong! Otherwise all dispositions would always be realized, but some may never be, because the triggering circumstances are never met. Use instance level d has_realization r as primitive ontological and causal connection. 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Relations III - has_realization Suggestion for a corresponding type level relation has_realization: A type of process R is the realization type of a disposition type D if and only if any instance of D is realized, then the realization is of type R: D has_realization R := x (x instance_of D → y: x has_realization y → y instance_of R) 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Relations IV - has_trigger We can split the fundamental nexus <disposition, trigger, realization> in two ways: relation between the triggering process and the disposition, e.g. between the fragility of a glass and its dropping. d has_triggerDt relation holding between triggering process and the realization of the disposition (the dropping of the glass triggers its breaking). r has_triggerR t d has_triggerDt r (d has_realization r r has_triggerR t) r has_triggerR t  d (d has_realization r d has_triggerD t) 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Relations IV has_trigger Trigger instances exist only for those particular dispositions that become realized. D has_triggerD T := x (x instance_of D → y (x has_triggerD y → y instance_of T)) R has_triggerRT if only one type T of trigger for R, all-some-structure holds: For all r instance_of R there is some t instance_of T and R has_triggerR T. 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Principles for sure-fire dispositions I „Realization principle“ if a disposition and its trigger are given, the realization will happen: ( D D is_a Disposition  T T is_a Process R R is_a Process D has_triggerD T D has_realization R dd instance_of D t t instance_of T) → r r instance_of R 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Principles for sure-fire dispositions II “Bearer Principle“ The bearer of the disposition is a participant of the realization process: (D D is_a Disposition  T T is_a Process R R is_a Process D has_triggerD T D has_realization R dd instance_of D  t t instance_of T  b b bearer_of d) → r (r instance_of R r has_participant b) The converse will not hold as a process is in general the realization of several dispositions of the interacting participants. 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

Relations between bearer, disposition, trigger and realization independent continuant has_participant trigger (process) has trigger (R)) has_bearer has_participant has_trigger(D) Realization (process) Disposition has_realization 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

„Multi-track“ and „Multi-trigger“ Something fragile does not always have to break into pieces, if struck, dropped or put under stress it may show cracks or splinter etc. No unique relation disposition - realization Option 1: fine-grain dispositions in such a way that multi-track dispositions are always resolved in many single-track ones. X has D1 with R1, T1, X has D2 with R2, T2 Probably not convenient for medicine, as one and the same disease may have different disease courses as realizations. 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

„Multitrack“: one disposition - different realizations Option 2: Allow diverse realizations Disjunctive list of possible realizations, often not mutually disjoint, but inclusive: Realisations of type of influenza: fever OR nausea, fever AND nausea etc. 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT

How to deal with general realization conditions? Outlook How to deal with general realization conditions? How to deal systematically with multi-trigger and multitrack? How to combine dispositions for joint effects (like vector addition of forces)? 06.07.2018 © 2009 UNIVERSITÄT ROSTOCK | PHILOSOPHISCHE FAKULTÄT