1. 1 DISPOSITION AND DISEASE * * * * * * Neil E. Williams (University at Buffalo) DISEASE ONTOLOGY WORKSHOP November 6-7 th 2006

2. 2  In order to construct a satisfactory disease ontology, a viable concept of disease is indispensable  Our aim is to provide such a concept that has wide appeal and is highly interoperable  As with any account of disease, the concept will form a tight circle with such concepts as health, normality, and adaptive success.

3. 3 Dispositions and Networks  We need a new way of thinking about disease that incorporates the best of the previous accounts, but is forward looking, and better suited to unified thinking about disease, without being reductionist.  I suggest that this new approach needs to focus on interactive networks formed by cells, and on the dispositional natures of the cells.

4. 4 Dispositions and Network  What I will present today is a brief introduction to the notion of dispositionality (and some connected notions) and how these can help inform a viable concept of disease

5. 5 What are Dispositions?  To ascribe to an object a disposition is to indicate that it possesses a certain potentiality.  It is to say something about how an object will be (known as the manifestation) if certain conditions (the stimulus) are to obtain.  eg.Fragility: --to say of a glass that it is fragile is not to say that it is now broken, but how it will be if not handled correctly

6. 6 What are Dispositions?  Dispositional properties are typically contrasted with ‘categorical’ properties— these being properties that capture how an object presently is.  The difference is often understood in terms of subjunctive conditionals: dispositional properties suggest or entail subjunctive conditionals, whereas categorical properties do not.

7. 7 What are Dispositions?  A subjunctive conditional is a form of if… then… statement where the antecedent (the if) has not been satisfied.  If the glass were to be dropped, then it would shatter.

8. 8 What are Dispositions?  3 Important Features of dispositions: (i) Independence --from manifestation and conditions (ii) Reciprocity --they act mutually (salt’s solubility and solution’s solvency) (iii) Intrinsicality --dispositions are not relations

9. 9 What are Dispositions?  Truthmaking: What makes our disposition ascriptions true or false?  Two important facts: (i) Dispositions can be lost or gained without ever being manifested. (ii) Two objects cannot be perfect duplicates yet differ in terms of their dispositions  We need some basis in which to ground our disposition ascriptions.

10. 10 What are Dispositions?  2 responses:  Each disposition has a categorical property as its ‘base’ that serves as its truthmaker  Dispositions are grounded in more basic dispositional properties which are less specific

11. 11 Other Terms in the Disposition Family  Propensity: ‘Propensity’ is typically used to denote a probabilistic disposition. Whereas dispositions are usually taken to manifest without fail upon their stimulus conditions obtaining, a propensity might not.

12. 12 Other Terms in the Disposition Family  Tendency: ‘Tendency’ is typically used to denote habitual disposition manifestation. Dispositions can exist without being manifested, but when they manifest regularly and reliably, we describe them as tendencies. Contrast the ability to smoke (disposition) with being a smoker (tendency). Contrast the ability to smoke (disposition) with being a smoker (tendency).

13. 13 Other Terms in the Disposition Family  (Causal) Power: Sometimes used synonymously with ‘disposition’, ‘power’ (or causal power) can also name those basic dispositional properties that are the truthmaker base for a variety of dispositional ascriptions.

14. 14 Why Think in Terms of Dispositions?  Laws track regularities in situ, ignoring infrequent or irregular behaviour  Cells have dispositions well beyond those mapped by laws or ever exercised  We have billions of clone cells engaged in unique activity; dispositions give place to these varied abilities

15. 15 Why Think in Terms of Dispositions?  Cells are potentiality centres—they are dispositional hubs ripe for interaction  Laws overlook wider ranges of abilities; they limit cellular roles  Dispositions are exercised reciprocally— causation is a mutual affair, a more apt treatment for networks

16. 16 THE DEFINTION OF DISEASE: A Proposal

17. 17 Disease = df A prolonged distortion of cellular network processes, wherein the activities of the network(s): (i) fall outside an acceptable normal range for the organism’s species, (ii)are not capable of remedy by the system itself without thereby distorting the activities of some other network, and (iii)tend to reduce the organism’s ability to cope with environmental pressures

18. 18 Distortions?  Perhaps the most important feature of this definition—and certainly the feature that is doing the most work, concerns the notion of distortion.

19. 19 Disease = df A prolonged distortion of cellular network processes, wherein the activities of the network(s): (i) fall outside an acceptable normal range for the organism’s species, (ii)are not capable of remedy by the system itself without thereby distorting the activities of some other network, and (iii)tend to reduce the organism’s ability to cope with environmental pressures

20. 20 what is a distortion?  A distortion is a deviation from a standard process  The difficulty here, as with any account of disease, is determining what count as the norms or standards by which a process would count as distorted.  It is here we get see the conceptual intertwining of between disease and health

21. 21 what is a distortion?  It is with regards to distortions and health that thinking in terms of dispositions (and the networks they form and mutually interact in) provides the greatest gain.

22. 22 what is a distortion?  A healthy process is a matter of various dispositions, some acting to bring about needed changes and responses (dynamic) and others working to maintain the status quo (static)  Health then is a matter of processes as judged over times, and is both dynamic and static: it is a series of smaller dynamic changes that account for (serve for) more general static dispositions.

23. 23 what is a distortion?  Norms are established by looking at what cells and networks can do and what they in fact do, and locating some statistical standards.  It is against this statistic backdrop of dispositional norms that distortions can be located and judged.

24. 24  As networks involve vast numbers of causally interacting cells, this can arise in numerous ways: (i) Changed environment (chemical, physical structure, obstruction) within the cell, across network, to whole organism) (ii) Resources (lack or surplus) (iii) Absences (of required partners or chemicals) (iv) Foreign Objects (germs, etc) (v) Instruction (transcription problems) (vi) Communication (chemical, internal, etc) Sources of distortion