1. Teleology and functions

2. Teleology - life’s aspirations
It is a co rre ct po sitio n that “true kno wle dg e is kno wle dg e by cause s. ”
And cause s ag ain are no t im pro pe rly distribute d into fo ur kinds: the
m ate rial, the fo rm al, the e fficie nt, and the final. But o f the se the final
cause ra the r co rrupts than advance s the scie nce s, e xce pt such as have
to do with hum an actio n. Francis Bacon, No vum O rg ano n, aphorism 3

3. Ends, and domains of
explanation
• Human intention and technology (te chne =def “art”)
– Psychological/cognitive (design)
– Ethical
• Natural processes
– Cosmic purpose
– Physical processes (planetary orbits)
– Living pro ce sse s - we are restricting ourselves to this
• Naturalising goals, the modern program
– To find ways in which goals can be made natural
• Anthropomorphism (seeing the world as we see ourselves)

4. Telos, a goal
• Te lo s = Greek for “goal” (fulfilm e nt or co m ple tio n,
co nsum m atio n, e nd)
• Plato: Mind is the cause for everything (External
telos)
• Aristotle: “that for the sake of which” (Internal telos)
– Four causes: material, formal, efficient, final
• Christian thought: Providence
– God foreordains all and designed all
• The Great Chain of Being: the world must be full
(principle o f ple nitude )

5. Aristotle’s finalism
• Four aitia (usu. trans. “causes”, better
“explanations”):
– Material (that which is changed)
– Efficient (that which changes matter)
– Formal (that to which it is changed)
– Final (that fo r which it is changed)

6. Kant and teleology
• In the Critiq ue o f Judg e m e nt (1790) he argued that
teleology was necessary to explain things that are
“both cause and effect of itself”, particularly living
things (§64)
• His was a natural teleology following natural laws
• Distinguished g e ne ric natural purposes from
individualnatural purposes
• Influenced many later biologists

7. Goals and purposes - where
do they come from?
• Traditional view:
– Goal-directed: change is targeted to
attaining an outcome (an e nd)
– Goals come from:
• External source: God (Platonic teleology)
• Internal source: Inner nature (Aristotelian
entelechy)
• External system <Natural Selection?>

8. Goals and purposes
• Modern view (Pittendrigh/Mayr):
– Goal-directed systems (teleological)
• I go to the fridge [in order] to find milk
– Goal-seeking systems (teleonomic)
• My digestive system processes my milk
– Goal-attaining systems (teleomatic)
• I drop the milk due to gravity

9. The old and the new
Teleomatic,
or end-
resulting
Teleonomic,
or end-
directed
Teleological,
or end-
seeking
Teleological,
or end-seeking
Teleonomic,
or end-
directed
Teleomatic,
or end-
resulting
Co g nitiv
e
Functio na
l
Lawlik
e
Idealist MechanistPro ce ss
e s

10. Progress in evolution
• Inevitability
• Net progress ve rsus local progress
• Eliminating progress
• Social progress and biological progress

11. Summary
• Modern teleology inverts the older kind
• Biological teleology is a by-product of
adaptation
• Teleology is an explanatory strategy

12. Functions
What are the y g o o d fo r?

13. Why care ?
“The organic world is full of functions, and
biologists’ descriptions of that world abound
in functional talk.” [Philip Kitcher]
• What biological things are functional?
• Are they functional in the things themselves?
• What function do functions have in explaining
biological systems?

14. Naturalising teleological talk
• Functions used to mean “goals” or “goal-
oriented behaviour”
• We want, after evolution, to see goals as
natural results - evolution is not goal-directed.
• Can we speak of functions without thinking
they are imposed from outside biology?

15. Philosophical Approaches
• Conceptual Analysis - finding out how some
group uses a term. Useful for that, but tells us
nothing else
• Scientific Analysis - how a scientist o ug ht to
use the term relative to a theory (e.g.,
evolutionary theory)
• Metaphysical Analysis - the nature of existing
things, no matter how we use words or what
works in a theory

16. Functions in biology
• Three versions
1 . Ho m e o static (what keeps it like that)
2. Etio lo g ical(where it came from)
3. Pro pe nsity (what it will do in future)
And one compound version: the Re latio nal
account (1 + 2).
• Vestiges - what is a vestige?

17. Homeostatic functions
• AKA CausalRo le or Syste m s-analysis functions.
Var: Cum m ins functions, or Ho m e o static
Pro pe rty Cluste rs
• “Homeostasis” = “keeping the same”
• Something is functional iff it contributes to the
homeostatic maintenance of the organism or
system of which the function-bearing trait is a
component. [def]

18. Problems with Homeostatic
functions
• Seems to require a prior knowledge (that it is
interesting and needs explaining, e.g., the
heart), or
• Assigns functions to uninteresting things (the
function of clouds in the rain cycle)
• Hence needs an etiological account to restrict
it to interesting biological functions

19. Etiological functions
• AKA Selective Effect functions. Var: Wright
functions, or proper functions
• “Etiology” = account of the causal origin
• Something is functional iff the appearance and
maintenance of that trait in the lineage of
which the organism is a member is due to past
contributions to the fitness of that lineage [def]

20. Problems with Etiological
functions
• Not required to do a functional analysis (Harvey
on the heart)
• Relies on knowledge or knowability of the
evolutionary history of the trait
• Involves using a problematic concept - homology
• What is the “proper” function of things? (Acorns
and squirrels): “Normal” versus “normal”

21. Propensity account
• Something is functional iff it has a
propensity to contribute to the future fitness
orsurvival of the lineage ororganism[def]
• How do we know what something will
encounter in the future?
• Mystery definition: “fitness” in the future

22. Modern History Account, and
Vestiges
• Something is a function if it has been
selected for in the recent past.
• Things can be retained for a while even if no
selection in their favour (adaptation versus
adapted distinction)
• Something can have had a function, but now
doesn’t - a vestige
• Deselected for old function, newly selected
for new function

23. Selection for function
• Function can persist when selection is
relaxed
• Traits no longer adaptive are vestiges
(Sober: were adaptatio ns , are now no t
adaptive )

24. Selection for function
• Vestiges for one trait (A) can be co-
opted as functions for another trait (B)

25. Normality Problem
• Something is a function whe n?
• Is the function of acorns to reproduce oaks,
or feed squirrels?
• “Proper functions” - Millikan’s etiological
account. Normal ≠ average or modal.
Then what?
• Normal for the clade or species? Or
homeostasis of that organism?
Millikan - etiology

26. Relational Account
• Combination of etiology (E-functions) and
homeostasis (C-functions)
• Trait X’s function in organismOis F in
selective regime S iff having Xis S increased
O’s fitness in S. A C-function increases
fitness in S to the extent that it maintains O
until it can breed. [def]
• “Normal” is thus dependent on reproduction

27. Conclusion
• We can be pluralists and think there are
at least 2 functions - E-functions and C-
functions and they have different roles
in explanations
• Or we can be monists and think that we
can combine E- and C-functions

28. John’s view
• We may not have naturalised functions but
we can speak of explanations as being good
or bad representations of biology
• Functions are something that appears in an
explanation, not in the biology itself. The
question is: is it a g o o d explanation? If it is,
then it is a good function.