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A Realist View of
Biological Functions
Ingvar Johansson,
Institute for Formal Ontology and Medical
Information Science, Saarbrücken
2004-09-29
PART I
CONSTITUENT FUNCTIONS
Screwdriver Function (i)
• Purpose:
The screwdriver is
used in order to
repair something.
• Causality:
The movement of
the screwdriver
causes a screw to
rotate.
Screwdriver Function (ii)
• Process Shape:
In its functioning, a
screwdriver creates
a four-dimensional
shape.
• Prototypicality:
Perfect screwdrivers create other
shapes than bad
screwdrivers do.
Heart Function (i)
• Purpose:
The heart pumps in
order to make the
blood circulate.
• Causality:
The heart causes
the blood to move.
Heart Function (ii)
• Process Shape:
In its functioning, a
heart creates a fourdimensional shape.
• Prototypicality:
Good hearts create
other shapes than
sick hearts do.
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.
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 nonmental 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?
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.
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.
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.
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.
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.
An Embryonic
Taxonomic Formula
SNAP (a + b + c) and SPAN (d + e):
(a) In the circulatory system (A),
(b) one function of the heart (B) is,
(c) to pump (V) blood (X) through the blood
vessel system (Y);
(d) this constituent function V has as temporal
parts of its functioning
(e) diastolic (P1) and systolic (P2) phases.
Taxonomic Formula for
Constituent Functions
SNAP (a + b + c) and SPAN (d + e):
(a) In the functional unit A,
(b) one function of the spatial part and subunit
B of A is,
(c) to V in relation to X, Y, Z, ...;
(d) this constituent function V has as temporal
parts of its functioning
(e) the phases P1 to Pn.
Analogy
Rationality
• Absolute rationality
• Relational
rationality
• Means-to-end
rationality
Functionality
• Intrinsic functionality
• Constituent
functionality
• Part-to-whole
functionality
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.
The New Problem Solved
1. Constituent function;
leads to an infinite regress.
2. Intrinsic function;
contains an anthropomorphizing of nature;
3. projected function;
contains an unscientific subjectivity.
Cutting the Gordian knot: We don’t have to
choose between 1, 2, and 3!
Earlier Endings
1. No position on universals is completely free
from problems, but immanent realism is by
far the least problematic position.
2. If immanent realism accepts the existence of
internal relations, it can give a realist
account of orderings and quantities.
3. Immanent realism can accept the existence
of process shapes, and it is compatible with
the use of prototypical concepts.
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.