The case of the probability of dysfunction

The case of the probability of dysfunction Françoise Longy (IHPST)

Plan • The origin of the question • The PHYS and ART proba of dysfunction • Can ART proba be seen as chances ? • Intuitively • Theoretically : Artefact kinds as non-physical(NP) real kinds • Probabilities grounded in NP real kinds • How to present the ART proba of dysfunction?

Origin of the question: Characterisation of function X has function F only if : X has an (objective) property O such that: • X is there becauseof O • Because of O, X has proba q of doing F X has proba p (p=1-q) to malfunction

Origin of the question: Characterisation of function X has function F only if : X has an (objective) property O such that: • X is there becauseof O • Because of O, X has proba q of doing F X has proba p (p=1-q) to malfunction Organisms and artefacts

Origin of the question: Characterisation of function X has function F only if : X has an (objective) property O such that: • X is there becauseof O • Becauseof O, X has proba q of doing F X has proba p (p=1-q) to malfunction

Origin of the question: Characterisation of function X has function F only if : X has an (objective) property O such that: • X is there becauseof O • Because of O, X has proba q of doing F X has proba p (p=1-q) to malfunction Because = a causal because

Origin of the question: Characterisation of function X has function F only if : X has an (objective) property O such that: • X is there becauseof O • Because of O, X has proba q of doing F X has proba p (p=1-q) to malfunction Because = a causal because The probability is grounded in some objective feature of the world

Origin of the question: Characterisation of function X has function F only if : X has an (objective) property O such that: • X is there because of O • Because of O, X has proba q of doing F X has proba p (p=1-q) to malfunction O = ??? The probability is grounded in some objective feature of the world

Which probability is pertinent relative to the function/dysfunction distinction? The DYSF-PHYS-proba of X ? The probability that the physical structure instantiated by X might not do F No X = a coffee machine, a light-bulb, … coming out of the factory

Which probability is pertinent relative to the function/dysfunction distinction? The DYSF-ART-proba of X ? The probability that X, which has been made in a bulb factory, might burn out after 5 minutes of normal use YES ? ≠ DYSF-ART and DYSF-PHYS probabilities DYSF-ART : the probability that X might possess (inherited) a physical make-up incapable of doing F DYSF-PHYS :The probability that the physical structure instantiated by X might not do F

The PHYS-proba as chances ? • No particular problem • The ART-proba as chances ? • ???

ART-Proba as chancesintuitively • Great importance of the quality of the production • Two opposite factors : cost/quality of production • Market  definite value of p • The assembly-lines (machines, work procedures, control mechanisms, …) are continuously planned, verified and adjusted to maintain a stable p X = a bulb coming out from a production plant The probability p that X will be defective

ART-Proba as chancestheoretical arguments Two ways of considering X • X as a physical object • X as an item of artefact kind Physical properties/functional properties • a≠b multirealizability • b is not definable in physical terms

ART-Proba as chancestheoretical arguments Two ways of considering X • X as a physical object • X as an item of artefact kind Physical properties/functional properties • a≠b multirealizability • b is not definable in physical terms b irreducible to a

to have a function ≠ to have a capacity = a historical property Organisms, = kinds defined by historical relations functional kinds Artefact kinds and Biological species are : • historical real kinds (Millikan) • NP (non physical) real kind

A NP real kind • Physical real kind (paradigm water, gold ..) A common physical micro-structure explains • High number of universally shared properties • NP real kind (paradigm lion, Renault 4 ..) External mechanisms explain • Historical continuity between members • High number of partially shared properties

A NP real kind • Physical real kind (paradigm water, gold ..) A common physical micro-structure explains • High number of universally shared properties • NP real kind (paradigm lion, Renault 4 ..) External mechanisms explain • Historical continuity between members • High number of partially shared properties Largely shared (Boyd, Millikan) Determinate proportion

A NP real kind • Physical real kind (paradigm water, gold ..) A common physical micro-structure explains • High number ofuniversally shared properties • NP real kind (paradigm lion, Renault 4 ..) External mechanisms explain • Historical continuity between members • High number of partially shared properties Largely shared (Boyd, Millikan) Determinate proportion

Types of real kinds and types of causes • A physical real Kind : gold (yellow, …) • A NP real Kind : corks (red crests, …)

Proximate and Ultimate causes Why has this cork a red crest ? • The physiological proximate cause • Because it has such genetic code • The evolutionary ultimate cause • Because he has inherited a cork genetic code Why his genetic code gave rise to a red crest Why he inherited the capacity to grow a red crest

NP Real Kinds and probabilities resulting from ultimate causes • Not all probabilistic properties are concerned • Only those resulting from mechanisms elected for regulating a particular ratio • The probability of being a female(organism) • Selected mechanisms regulate the male/female ratio • The probability of dysfunction (artefact) • The proportion of defective items in regulatedby • Factory mechanisms • Firm mechanisms • The Market mechanisms

What nature hasthe DYSF-ART probability ? The probability that an artefact item is defective It is not a real frequency • it does not result from statistical data concerning the actual population of Xs • It corresponds to the ratio of defective items a series of mechanisms (at factory, firm or market level) tends to produce under normal conditions • Frequency in the actual population may differ from the one grounded in the NP-real kind mechanisms

How to qualifythe DYSF-ART probability ? The probability that an artefact item is defective It measures something like a propensity • It measures an objective feature of the world which is not a frequency However, speaking of propensity is odd • An item X could then have 2 ≠ propensities of doing F X could have the physical propensity p to do F, but the real kind propensity q (q≠p) to do F ! • it is not a tendency rooted in what the item is all by itself

How to qualifythe DYSF-ART probability ? The probability that an artefact item is defective It is rather a property at kind (population) level • If a tendency is involved, it is a tendency rooted in the factory (firm or market) mechanisms However, calling it simply a frequency is misleading • The objective fact it refers to is not an effective frequency in a real population • It is the frequency that an actual series of mechanism, involved in maintaining a NP real kind's unity, tend to produce Should we then say something like "ideal frequency NP real kind mechanisms tend to produce"?

The case of the probability of dysfunction