A Realist View of Biological Functions

1. A Realist View of Biological Functions Ingvar Johansson, Institute for Formal Ontology and Medical Information Science, Saarbrücken 2004-09-29

2. PART I CONSTITUENT FUNCTIONS

3. Screwdriver Function (i) • Purpose: The screwdriver is used in order to repair something. • Causality: The movement of the screwdriver causes a screw to rotate.

4. Screwdriver Function (ii) • Process Shape: In its functioning, a screwdriver creates a four-dimensional shape. • Prototypicality:Perfect screw-drivers create other shapes than bad screwdrivers do.

5. Heart Function (i) • Purpose: The heart pumps in order to make the blood circulate. • Causality: The heart causes the blood to move.

6. Heart Function (ii) • Process Shape: In its functioning, a heart creates a four-dimensional shape. • Prototypicality:Good hearts create other shapes than sick hearts do.

7. The Problem of Functional Purpose (i) • Only beings with consciousness can have purposes and intentions and be directed towards a distant future. • The purpose and function of the screwdriver is a projected (artificial) purpose and function. • The function of the screwdriver is not a monadic property that inheres in the screwdriver.

8. The Problem of Functional Purpose (ii) • Is also the function of the heart merely a projected function? • Can there be intrinsic (natural) functions of material entities, i.e., can a function be a non-mental monadic property of a material entity? • If not, can functions be reduced to: a) causality (mainstream view); b) causality + social projections (Searle);c) causality + social projections + process shapes?

9. The Problem of Functional Purpose (iii) • If any of these reduction theses is correct, then scientists in biology and medicine should no longer talk literally about functions. • But they do! • All the reduction theses are philosophical theses. • And so is the non-reduction thesis. • Ontology and science overlap.

10. The Problem of Functional Purpose (iv) • If the function of the heart is to pump blood, then it has this function during a time interval. • Functions: The functioning of something is extended in time. • Causes: The effect of a direct cause arises simultaneously with the cause or in the next moment. • Literal functionality is more than causality.

11. The Problem of Functional Purpose (v) • Functions: The functioning of something is extended in time. • Purposes: The purpose of an action might lie in a distant future. • Process shapes are not purposes. • Not even prototypical process shapes are necessarily purposes. • Literal functionality is more than a matter of being a prototypical process shape.

12. The Problem of Functional Purpose (vi) • Is literal functionality then necessarily intrinsic functionality, i.e., a purpose that as a non-mental monadic property inheres in the function bearer? • No! • Everyday function talk does not distinguish between the concepts of intrinsic functions and constituent functions.

13. The Solution to the Problem: Constituent Functions • A constituent function may also be called a part-to-functional-whole function. • A constituent function is irreducibly relational in character. • The constituent function of the heart (part) is to pump blood in the circulatory system (functional whole) who has the function of transporting substances between other bodily systems.

14. An EmbryonicTaxonomic Formula SNAP (a + b + c) and SPAN (d + e): • In the circulatory system (A), • one function of the heart (B) is, • to pump (V) blood (X) through the blood vessel system (Y); • this constituent function V has as temporal parts of its functioning • diastolic (P1) and systolic (P2)phases.

15. Taxonomic Formula for Constituent Functions SNAP (a + b + c) and SPAN (d + e): • In the functional unit A, • one function of the spatial part and subunit B of A is, • to V in relation to X, Y, Z, ...; • this constituent function V has as temporal parts of its functioning • the phases P1 to Pn.

16. Rationality Absolute rationality Relationalrationality Means-to-endrationality Functionality Intrinsic functionality Constituentfunctionality Part-to-wholefunctionality Analogy

17. The New Problem • A constituent function is a function only in relation to an encompassing functional whole. • What then about this functional whole? What kind of functionality does it have? • Available options: 1) constituent function;2) intrinsic function;3) projected function.

18. The New Problem Solved • Constituent function; leads to an infinite regress. • Intrinsic function; contains an anthropomorphizing of nature; • projected function;contains an unscientific subjectivity. Cutting the Gordian knot: We don’t have to choose between 1, 2, and 3!

19. Earlier Endings • No position on universals is completely free from problems, but immanent realism is by far the least problematic position. • If immanent realism accepts the existence of internal relations, it can give a realist account of orderings and quantities. • Immanent realism can accept the existence of process shapes, and it is compatible with the use of prototypical concepts.

20. Today’s End 4. (a) The existence of constituent functions suffices to explain the objectivity of biological functions and functionings. (b) Constituent functions can be accounted for within the framework of immanent realism.