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1/26

Exemplars and Scientific ChangeAuthor(s): David L. Hull

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2/26

Exemplars and

Scientific

Change'

David L. Hull

The

University of

Wisconsin-Milwaukee

A

recurrent

theme

in

the "new

philosophy

of science"

is the

impor-

tance

of

temporally

extended

conceptual

entities termed

variously

dis-

ciplinary

matrixes

(Kuhn

1970),

research

programs (Lakatos

1970),

scientific

disciplines

(Toulmin

1972),

theories

(McMullin

1976), and

research traditions (Laudan 1977). Each of these macro-conceptual en-

tities contains a

rich

heterogeneity

of constituent

elements. For ex-

ample, Kuhn's

(1970, pp.

183-187)

disciplinary

matrixes

("paradigm"

in

his

global

sense)

include

symbolic

generalizations,

metaphysical

views,

models,

values,

and

exemplars as concrete

problem

solutions

("paradigm"

in the

narrow

sense).

All

of the

conceptual

entities

listed above are

"historical entities"

or

"continuants",

the

sorts of

things

that

can

change

through time. Toulmin

(1972)

and Laudan

(1977)

permit

total

changeover

in

elements

just

so

long

as

the transformation

is

gradual

and

the system

remains cohesive in

the

process.

Others,

such

as

Lakatos

(1970),

insist on

the retention

of a "hard

core" of some

kind.

Numerous problems

have

arisen with

respect

to

the notion of

concep-

tual

historical entities. In

this

paper,

I

am

concerned

with

only

two--

how

they

are

to be

individuated and

named.

If

such

conceptual

systems

as

"Darwinism"

are

internally quite

heterogeneous,

if

different

concep-

tual

systems contain

instances of

many

of

the "same"

concepts,

if

a

conceptual

system

can

undergo a total

transformation of

its

elements

while

remaining the

"same"

conceptual

system, how are

we to

tell

whether

we have

one

conceptual

system

or two,

either at any

one

time or

through

time? How

can we

name

such

slippery entities and

continue

to

apply the

same

name to

the same

entity

through time?

When

disagreements

arise,

how are

we to

reconcile them?

In

this

paper

I

propose

to answer

the

preceding

questions by

extend-

ing

Mayr's

(1982) notion

of

"population

thinking" to

thinking itself

(Ghiselin

1981).

As

Mayr (1982)

continues to

emphasize, anyone

who

thinks

that

the

populations that

function

in the

evolutionary process

are

populations of

similar

organisms

has

misunderstood the

fundamentals

PSA

1982,

V lume

2,

pp.

479-503

Copyright

(9

1983

by the

Philosophy of

Science

Association

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3/26

480

of population

thinking.

The reason

that the notion of "identity by

de-

scent"

is so important

in

biological

evolution is

that the

only

similar-

ities

and

differences that

matter in the

evolutionary process

are

those

that

exhibit this sort

of

"identity"

or lack of it.

If

populationthink-

ing is to be extended to thinking, conceptual populations must be treat-

ed

in the same way.

Biological species

are

internally quite

heterogEne-

ous. They too can change

through

time, regularly turning

over their

constituent

organisms,

possibly

modifying every

trait that might

be con-

sidered

defining. Rarely do two species

share the same "elements"

in

the

sense of the

same

organisms,but

the members

of two or more species

are frequently

characterized by

instances

of the same trait. The

hood-

ed

and

the

carrion

crow both have

black feathers.

Although

evolving

species

are

just

as

slippery

as

evolving

conceptual

systems, biologists

have worked

out ways

of

individuating

and

naming them,

i.e.,

the

type

specimen method.

In the first

two sections

of

this paper,

I explain

how

this method arose in the context of theories of special creation and was

then modified

in

response

to the acceptance

of evolutionary theory.

I

then show how

this

method can be extended

to handle

social

groups (such

as the Darwinians)

and

conceptual

systems (such

as Darwinism).

1. Species as

Natural Kinds

During the belle epogue

of natural

history

in

the

18th and

19th cen-

turies, systematics

included

a

greater

element

of

philately

than

pres-

ent-day systematists

like to recall. During

this period,

the

most wide-

ly held view on

the origin of species

was

some form of special

creation.

According

to some creationists,

the

first

members

of every species

were

created in the beginning, and the resulting species remained unchanged

thereafter.

According

to other creationists, species

were

introduced

sequentially

in

time,

either

in

huge

masses

or

a

few at a time, as other

species

went

extinct.

Many

naturalists believed that

both origins and

extinctions

are

miraculous

events;

others that origins

are

miraculous

while

extinctions are natural;

still others that

both processes

are

equally

natural.

One

implication

of all versions

of creationism

is that

a finite number of species

exist at any

one

time

in

human history.

Hence,

the

discovery of previously

unknown

species had a

certain urgen-

cy

to it. The

explorers

who

crawled the

surface of the earth felt

that

they

had best

hurry

and find

their species

before they

were all taken.

Like stamp collectors, the keepers of various "cabinets" had as their

task to obtain

for their collections

at least one

good specimen

of

every

species.

The

special

creationist

view of

species

was usually

coupled

with the

philosophical

view that species

are

natural

kinds. Like other

natural

kinds,

species

were held to be eternal,

immutable,and

discrete.

Quite

obviously,

creationists could not

very well believe

that all

species are

extensionally eternal;

i.e., that

throughout all

time there

existed rep-

resentatives of every species.

Instead, they held

that species

are

somehow built

into the fabric of

the universe.

Species exist

even

when

they

are not exemplified.

The sense

in

which species that

are not

ex-

emplified

could continue to exist varied

extensively.

At least one

nat-

uralist can be found advocating

every metaphysical

position on the

sub-



4/26

481

ject.

In

any case,

a

common

belief

among

creationists

was that

species

could cease to be

exemplified

every

once in a

while and then become

re-

exemplified

later. Naturalists also

thought

that

organisms

on

occasion

could change their species, but an organism changing its species was

not

the

same

thing

as

species

themselves

changing.

It was akin to

an

alchemist

transmuting

a base metal into

gold.

However, by

the 19th

cen-

tury,

most naturalists

thought

that

species'

boundaries

were

largely in-

violate.

The characteristic

of

species

as

natural kinds

that roused the

great-

est amount of discussion was not their

immutability

but the

discretEness

of their

boundaries

in

conceptual space.

On

the traditional

"essential-

ist"

view,

all

genuinely

meaningful

terms must

be defined

by

means of

characteristics

that

are

severally

necessary

and

jointly

sufficient for

membership. Either

a

geometric

figure

is

a

triangle,

or

it

is not.

No

borderline cases can possibly exist. Naturalists at the time were ob-

viously aware

of

variation

both within

species and between

them. Not

all

members of a

particular

species

were

identical

to

each

other,

and

at time

borderline

cases existed.

However,

they

took

it

as

their

task

to

see

through

all

this

accidental variation to

the

essential

nature

of

each

species

and to

capture

its

essence

in

a

definition

or

"diagnosis"

(to

use

the taxonomic

term).

Given a

correct

definition

of

a

particu-

lar

species,

nearly

all

organisms

belonging

to

that

species

should

pos-

sess

all

its essential

characters.

Any variation

that

might occur

was

thought

to

be merely a

function of

the limitations of

nature,

the

fail-

ure of a

principle.

Numerous

present-day authors

have

claimed

that no

one from

Aristotle

to the

present

ever held the

preceding view

of

species.

Certainly no

philosopher or

naturalist

held

precisely

the view

described

above, but

views

of

this

sort were

just as

surely

common

during the

period

under

discussion. For

example,

the

importance of the

discreteness of

spe-

cies'

boundaries can

be

seen in a

dispute

between

William

Whewell

(1847,

1853) on one

side

and John

Stuart

Mill (1843,

1872)

and W. S.

Jevons

(1892)

on

the other.

According to

Whewell (1847,

vol. 1,

p.494),

natural

kinds in

mathematics

and

certain

areas of

physics

are

absolute-

ly

discrete,

while in other

areas such as

biology, equally

sharp

bound-

aries

had

yet

to

be

discerned.

Hence, the

traditional

Method of

Defi-

nition could be used for the former

sort of

natural

kinds, but

for the

latter, Whewell

devised what he

termed the Type

Method.

According to

this

method,

a

typical

representative

of each

species

is chosen

as its

"type"

and

other

members of the

species are

included in the

species by

means

of

their

relation to

it.

Whewell

(1847, vol. 2,

p. 12)

was aware

that

zoologists

defined the

species

category

in terms

of

"individuals

which have,

or

may have,

sprung

from

the same

parents."

However,

the relation

that

another or-

ganism in

a

species must

have to

its type

was

not

genealogical

but a

certain

degree

of

similarity.

Whewell

justified

replacing

genealogy

with similarity by noting that "individuals so related resemble each

other more than

those which

are

excluded

from such

a

definition."

The

only

unusual

thing

about Whewell's

Type

Method

was that

the

conceptual



5/26

482

boundaries between

species

need not be

absolutely

sharp.

For

Whewell

species

formed a

"cluster",

some

organisms

being

more central

than

oth-

ers. Even

so,

he

thought

that these

fuzzy

boundaries

were real.

They

no more

changed

through

time

than

did

the

absolutely

discrete

boundar-

ies of more traditional typologists. Nor did Whewell believe that the

distributions of actual

organisms

in

conceptual

space

were ever

per-

fectly

continuous.

Although every point

in

character

space might

be

occupied by an organism,

the numbers varied

significantly.

Most

organ-

isms in

a

species tended to cluster

around the

type.

And

in most cases

large expanses of

character space

between

species

were

unoccupied.

If

"essentialism"

is merely

an

invention of later

evolutionists such

as

Mayr

(1982),

as some

authors have

claimed, then Whewell's

minor

modification

should hardly have

elicited much of a

response.

After

all,

for

Whewell, species

remained eternal and immutable.

They

simply

were

not absolutely discrete. Whewell (1847, vol. 1, p. 493) himself sus-

pected that

his

views on

the subject were "so

contrary

to

many

of the

received

opinions

respecting the

use of definitions and

the nature of

scientific

propositions, that

they

will

probably appear to

many

persons

highly

illogical and

unphilosophical." He

was right.

Both Mill (1872,

p.

472)and Jevons

(1892, p. 723)

rejected

Whewell's

Type Method.

They

argued that either it reduced to

the traditional

Method

of

Definition

or it

was not an

acceptable method of

classification; for

further

dis-

cussion see Ruse

(1979,

pp. 125-126)

and Hull

(1981,

vol.

2, pp. 133-

137).

On

the

"typological" or "essentialistic" view

of

species,

collecting

was relatively easy. An occasional mutilation or monster to one side,

any specimen

could

equally

well

serve as a

representative

of

its

spe-

cies.

Any

trait that was

truly

variable could

not

possibly

be

part

of

a

species' essence. A

naturalist

might

sample

his

species

widely but

not for the

purpose

of

reflecting

any

variation

he

might

find in

his

diagnosis.

To

the

contrary, the

purpose

of

studying variation

was to

eliminate it. On

this

view,

definitions

(or

diagnoses)

are the

goal of

systematics,

and after

sufficient

study,

competent

observers must

nec-

essarily agree

about

appropriate

definitions. For

example,

two natu-

ralists

collecting

on

opposite sides

of

Australia

might stumble

upon

organisms

belonging

to

the same

species.

If

these

collectors are com-

petent naturalists, they must produce precisely the same definitions.

In

actual fact, the

state

of

taxonomy

was

just the

opposite

of what

the

typological

species concept would

lead one to

expect. The

more ex-

tensively

a

group

was

studied,

frequently the more difficult it

became

to delimit

its boundaries. At a

single

location, species are

easy

enough

to

distinguish

from

each

other,

but if

species

are

studied

across

their

ranges, their definitional

boundaries

become

increasingly

diffi-

cult

to discern.

Attempting

to

integrate fossil species

with extant

forms

only complicates matters

further. As a result,

systematists work-

ed and

reworked their

groups

as

regularly as

stock

brokers churn their

accounts

and

with much

the same effect. Of

greater

significance, the

diagnoses so carefully constructed by systematists should have been the

key

to

resolving

difficult

cases.

Time

and

again, the

specimens

were



6/26

483

what helped.

Time and

again,

later workers

could

not tell from the

pub-

lished

diagnoses

which

species

the

systematist

had

studied,

but

an

ex-

amination of his

specimens

often

helped

bring

some order

to the

chaos.

Darwin and his famous finches

is an excellent case in

point.

According

to

the

traditional

legend,

Darwin was led

to

speculate

on

the

origin

of

species

because

of the

distribution

of the finches

which

he observed on the various islands

of

the

Galapagos

Archipelago

and

later used

these

observations to

support

his

theory

of

evolution.

As

Sulloway(1982)

has shown

in

some

detail,

the historical evidence

does

not

support

this

legend;

see also

(Herbert

1980).

While at

the

Gala-

pagos

Islands,

Darwin

gives

no hint

that he had

any

doubts

about

the

immutability of

species.

Not until nine months

later,

in

1836,

does

he

record

any doubts

on

the

subject

(Sulloway

1982, p. 12).

Nor

was Dar-

win,

on his return to

England,

able to use his

Galapagos

collection to

support the theory of evolution because his collecting had been too hap-

hazard.

In

particular,

he

did not

always

record

the location at

which

the

specimen

was

obtained,

precisely

the

biogeographic

information need-

ed

to test his views on

speciation.

As

Sulloway

(1982, p.

18)

points

out,

locale

is not all

that

impor-

tant

for

a

creationist,

certainly

not as

important

as

it is for

anyone

who

believed,

as

Wallace

(1855, p.

186)

did,

that

every

"species

has

come into

existence coincident both in

space

and

time

with

a

pre-ex-

isting

closely allied

species."

Wallace

had a

decided

advantage over

Darwin.

He went

on his

voyage intent on

testing

his

evolutionary hy-

pothesis. He

could

keep

his

eye

out

for

the relevant data. Darwin had

to

do

everything

in

retrospect, and too

often he had

not

made or

record-

ed

the relevant

observations.

Legend

notwithstanding, Darwin

did

not

use

his finches

as a

paradigm

example

of

the

evolution of

species

by

means of

natural

selection in

the

Origin

(1859)

because

he did not

have

the

necessary

information.

Upon

returning

to

England,

Darwin

sought the aid

of

a

variety of

specialists

in

curating

his

collections.

Chief

among

these

was the

ornithologist

John

Gould

(1804-1881). As it

turned out,

Darwin's ini-

tial

guesses about

the

relations

of his

birds,

including the

Galapagos

finches, were

mistaken. For

example, many

of

Darwin's

varieties,

Gould

claimed were distinct species. With the aid of the collections of oth-

er

members of

the

crew of

the

Beagle,

Darwin

produced what

has

been

termed

a

"taxonomic

nightmare".

Some

order has

been

brought

to

Darwin's

finches by

subsequent

workers

but not

because

of

Darwin's

published des-

criptions. It

was

his

specimens

and

those of

his

shipmates

that

were of

the

greatest

help.

If

these

specimens had

not

been

preserved, later

systematists

would

have been

at a

loss to

work

out the

actual

identities

and

relations

of

Darwin's finches.

Not until

Lack's

(1947)

work

did the

myth of

Darwin's

finches

become a

reality.

2.

The

Type

Specimen

Method

The

acceptance of

evolutionary

theory

transmuted

numerous

curiosities,

such as

Wallace's

1855 law,

into

solved

problems

(Laudan

1977). It

also



7/26

484

changed

the relation between organisms

and their species. As before,

organisms

are

part

of their

genealogical

nexus,

but no

longer

could

one

assume,

as Whewell had,

that

genealogical

relations

must

universally

coincide

with

similarity

relations.

Although

the point

was extremely

slow in making itself felt, similarities encapsulated in definitions

had been

displaced by organisms as

nodes

in

the

genealogical nexus.

If

species evolve

gradually through

time,

one changing into another or

one

species splitting slowly into two,

then

the search

for

"typical"

mem-

bers of a species

is

questionable

at best. For

example,

upon reading

Whewell's

(1853) discussion

of his Type Method,

Darwin responded,

"On

my theory

an

'Exemplar'

is

no

more wanted than to account

for the like-

ness

of members

of one Family." (Ospovat 1981,

p. 260). Although

this

comment

is

more

than a little cryptic,

Darwin

rejected

the abstract

ar-

chetypes

of idealist

philosophers

and

replaced

them with

actual ances-

tors,organisms

that

need

not

in

every

case be

typical.

For

Darwin spe-

cies became segments

of the phylogenetic tree,

as historical

as

the Ba-

roque period. Just as

the Baroque

period

will

never return,

extinct

species

cannot

re-evolve.

Because

of the terminological

confusion

of

the

sort described above,

systematists

gradually evolved systems

of rules

and

regulations

formal-

ized in various

codes

of nomenclature. As these

codes were

developed,

a

very

strange notion

began to

emer?e

and become

central to taxonomic

practice--the

type specimen

method.

As

the

name indicates, initially

systematists

strove to designate as the type

specimen for

a species a

typical

member.

If

later workers came to think that

a

particular

type

specimen

was

not as

typical

as it

might be,

they replaced

it

with

an-

other specimen. The resulting confusion, rapidly led systematists to

put

an end to this practice

and to rule that once a specimen

had been

designated

as a type specimen,

it could not be replaced except

in cases

of

duplication.

The sole function

of

the

type

specimen

is to be the

name bearer for

its

species.

No

matter in which

species

the

type speci-

men

is

placed,

its name

goes

with

it. The crucial decision made

by sys-

tematists

was to

disentangle

two different

functions for

specimens,

that

of

typifying

their

species

and that

of

designating

them rigidly.

For

those species

that

form unimodal distributions,

the notion of a

"typi-

cal"

member

has some

point,

but

given

the wide

variety

of

character

distributions

exhibited

by

actual

species

in

nature,

too often it does

not.

Instead an

array

of

specimens

is

necessary.

As

Mayr

(1969, p.

369) has expressed

this

position,

"Species

consist of variable

popula-

tions,

and no

single

specimen

can

represent

this

variability.

No

single

specimen

can be

typical

in

the Aristotelian

sense."

In

cases

in

which species

cannot be characterized

in

terms

of simple,

coincident

unimodal

distributions of

characters,

no

specimen,

including

the

type specimen,

could

possibly

be

"typical"

of its

species.

However,

even

in

those

special

cases that fit our common

sense

intuitions

about

species,

there

is still

ample justification

for

keeping

the

naming

func-

tion

separate

from

description.

With the rarest

of

exception,

any org-

anism chosen at random

must

belong

to

a

species,

one

species

and

one

species only. Our ideas of character distributions, however, can be

mistaken.

A

systematist

may think that he has

collected a

variety of



8/26

485

specimens

from

a

single

species,

when later workers decide

that

his

"single"

species

actually consisted of two

or more

sibling

species.

Hence,

even

in

those cases

in

which the selection of

a

"typical"

spec-

imen

is

feasible,

the likelihood

that increased

knowledge

will

lead

systematists

to

change

their minds

about character distributions

is

sufficiently

high to warrant

excluding

the

name

bearing specimen

from

these exercises.

No matter how

typical

or aberrant

systematists

may

take

a

type specimen

to

be at

any

one

point

in

time,

it can serve

just

as well as the name bearer

for its

species.

As

Simpson

(1940, p. 413)

put

the

point

in

his seminal

paper,

"items

called

'types'

have

been used

in

taxonomy

in three

ways:

as bases

for

definitions,

as standards of

comparison,

and as fixed

points

to

which

names are attached. The modern

conception

of

taxonomy

as

involving

the

inference of

population

characters

from

samples

makes

it

impossible

for

the same items properly to serve all three of these purposes." Simpson

accordingly recommends

reserving

the

term"type"

for

the

last

function,

as

a

fixed

point

for

attaching

a taxonomic name to a taxon

(see

also

Williams 1940). Later

Simpson

(1945, p.

29) expressed

his

position

on

type

specimens even more

forcefully.

"It is

a natural but

mistaken as-

sumption

that

types

are somehow

typical,

that

is,

characteristic,

of

the

groups

in

which

they

are

placed.

It

is,

of

course,

desirable

that

they should be

typical because then

they

are

less

likely

to be shifted

about from

group

to

group,

carrying

their names

with them and

upsetting

nomenclature,

but there is no

requirement that a

type be

typical, and

it

frequently

happens that it is

quite aberrant."

Whether Simpson

was enunciating

a new but

compelling

position or only

putting

into words a

conviction

that had

already

been

widespread for

some

time is

difficult to

decide. But

with

surprising

rapidity, the

role of

the

type specimen as

a

name bearer

became

standard

taxonomic

practice.

For

example,

in

the

first modern

textbook

on

biological sys-

tematics, Mayr,

Linsley

and

Usinger

(1953, p. 236)

state, "It

is very

difficult to

characterize or to

define a

taxonomic

entity

solely by

means of

words. As a

result, many of

the

Linnaean and

early

post-Lin-

naean

species,

particularly

among

the

invertebrates,

are

unidentifiable

on

the

basis of

the

description

alone. It is

obvious

that more

secure

standards are

needed

to tie

scientific

names

unequivocally to

objective

taxonomic entities. These standards are the types, and the method of

using types to

eliminate

ambiguity is

called

the type

method."

On

one

interpretation, all

the type

specimen

method does

is to

free

the

type

specimen from

participating in the

inevitable

disagreements

that

go on

continually in

biological

systematics

about splitting,

lump-

ing

and

shifting

boundaries.

Once a

systematist has

decided on

his spe-

cies

and their

limits,

he

can then check

where the

specimens designated

as

types happen

to

fall and assign

names

accordingly.

If

he recognizes

a new

species

for

which there is

no type

specimen, he

must

designate a

particular

specimen as such.

If

two specimens

previously

designated as

the

type specimens for different species end up in a single species,the

temporally prior

type

specimen

becomes

the name

bearer for

his newly

combined

species and

the other

type

specimen is

demoted.

As might be



9/26

486

expected,

the

type specimen

method

is not without its difficulties.

For

example,

Randall and

Nelson

(1979) point

out a case in which the

same

specimen of a

parrotfish

was

designated

as the

type specimen

for

three

different species

belonging to two different genera

Periodic

congresses

are held to resolve such problems.

Nor does the type specimen method eliminate

entirely

a

role

for the

study of character distributions

in

systematics.

On a

conservative in-

terpretation of this

method,

the

diagnoses

published by systematists

define the designated

species.

In

each case, though

the

type specimen

may be aberrant, it

must at least

fall

within the range of variation

established

by

the

systematist (Heise

and Starr

1968).

On

a

more radi-

cal

interpretation, the interpretation

I

favor,

character distributicns

are

secondary

to the

genealogical

nexus. The

type specimen,

like

all

organisms,

is

merely one node

in

this

nexus.

The

type specimen

method

works by tying down a name to one chunk of the genealogical nexus via

a

single node

in

that nexus.

No

matter how the boundaries

are

reas-

sessed, whatever species

includes a

particular

type specimen

must be

called

by the name

associated with that specimen. Characters

are3still

important but only as

an aid to inferring the genealogical nexus.

3. Scientific Communities

In

recent years

an

increasing number of authors have been

paying at-

tention to the social structure of

science, especially

the

social

groups into which scientists

organize themselves.

Philosophers

tend to

be extremely suspicious

of

such

concerns, fearing

that some sort of

social

relativism lies

behind them.

However,

I

think that scientific

communities

play

several

important roles in science,

roles that have

little

to

do with

such epistemological concerns. For

example, much of

the coherence and

continuity

that is so characteristic of

conceptual

development

in

science results from

the coherence

and

continuity of

the

groups

of

scientists

developing

these views.

Similarly, unless at-

tention is paid to cooperating and

competing factions

in

science, many

of

the

positions

that

scientists take on

particular issues are

all

but

inexplicable.

Frequently, a relatively minor tenet in

an emerging re-

search

program

becomes elevated in

importance

because of the incessant

attacks

on

this tenet

by the opponents

of

the

program.

One

of the

most common

and intuitive

ways

of

dividing scientists in-

to

groups

is

by

means of

intellectual

agreement.

"A

paradigm is what

the members

of

a scientific

community

share, and, conversely,

a

scien-

tific

community consists

of

men

who share

a

paradigm."

(Kuhn 1970, p.

176). Unfortunately, this position

simply will not do. If

by "para-

digm"

Kuhn means disciplinary matrix,

rarely do any two

scientists a-

gree

totally on every element of their

common matrix.

If

by "para-

digm" Kuhn means

exemplar, differences

of

opinion

still

remain. Cer-

tainly much more agreement

exists

among the members of a scientific com-

munity about the value of their

concrete puzzle

solutions, but in every

community

I

have

studied, the

agreement is never total. As Palter

(1974, p. 314) pointed out some time

ago in reaction to

the writings of

Kuhn

and

Lakatos,

any concensus that might exist on a

given scientific



10/26

487

topic is

generally

incomplete.

Just

as

biologists

were forced

to

aban-

don

definitions in terms

of

statistical

covariation,

philosophers

might

well

relax

the

requirement

of

total

agreement

for

scientists'

belonging

to

the same scientific

community.

All

they

have to

do is

agree

on

e-

nough of the more important issues. But even this more reasonable po-

sition

is too

stringent.

Whether one deals

with such massive and

rela-

tively

insignificant

groupings

as

"physicists"

or

with

such small

ephem-

eral

research

groups

as

the Cold

Spring

Harbor

group,

disagreements

can

be

found

among

their

members even on

fundamentals.

Although

the

scien-

tists

involved

go

to

great

lengths

to

emphasize

their areas of

agree-

ment,

one

extremely

important

feature

of

science

(and

possibly

other

endeavors

as

well)

is

that scientists

can

cooperate

with each other

even

when

they

disagree.

The

appropriate relation

for

"defining"

the

groups

of

scientists

that

function in

the

ongoing

process

of

science is

cooper-

ation

and not

agreement.4

For

example,

if

one

attempts

to

define the

Darwinians in the

first

decade

after

the

publication of

the

Origin

in

terms of

basic

agreement,

one

gets an

extremely

motley

group.

In

the

early

years,

J.D.

Hooker,

T. H.

Huxley, and

Charles

Lyell were

important Darwinians. A.

R.

Wal-

lace and

J. S.

Henslow

might be

included

as

welL Adam

Sedgwick, Richard

Owen,

William

Hopkins and

St.

George Jackson

Mivart

were

important

anti-

Darwinians.

No

weighting of

substantive

beliefs

about

science

or

bio-

logical

species

produces

anything like

this

division.

In

1859

neither

Henslow

nor

Lyell

believed

in

the

evolution

of

species.

Henslow

died

unconvinced, while

Lyell came out

openly

for

evolution

only

in

1868 and

then

grudgingly

with

reservations.

Conversely,

both

Owen and

Mivart ad-

vocated evolution, just not "Darwinian" evolution, but the same

can

be

said

for

Huxley and

Wallace.

Huxley

agreed

with Darwin

about

the

import-

ance

of

natural

selection

but

thought

that

speciation

might be

more sal-

tative

than did

Darwin,

while

Wallace

disagreed

with

Darwin

on

a

variety

of

counts

(Kottler

1980).

Although

I

think

that

there

are

excellent

reasons

for

paying

atten-

tion

to

areas

of

agreement

and

disagreement

between

scientists,

I

think

it

would

be

a

serious

mistake

to

delimit

scientific

communities

in

this

way.

Instead

the

variety of

ways

in

which

scientists

cooperate

with

each

other

in

their

research

are

much

more

appropriate

relations

to in-

tegrate scientists into groups. Among these relations are co-authoring

papers,

recommending for

positions

and

honors,

citing

areas

of

agree-

ment in

published

papers

while

reserving

disagreements

for

private

cor-

respondence,

and

so

on.

If

these

measures are

used for

the

Darwinians

during

the

early

years,

a

single

community

materializes

quite

forceful-

ly. Of

course,

there

is

a

sense

in

which

anyone who

pledged

allegiance

to

"Darwinism"

counts

as a

"Darwinian",

but

I

do not

think

that

the

Dar-

winians in

this

broad

sense

can

possibly

be

said

to

form a

"community"

or

a

"group".

Discerning

genuine

scientific

communities

is

a

difficult

undertaking,

as

difficult

as

delineating

biological

species,

so

difficult

that one

is tempted to take the easy

way out.

Just

as

it is

easier to

define

bi-

ological

species in

terms

of

characters than

to

individuate

them

by



11/26

488

means of their

genealogical

relations,

it is easier to delimit

scientif-

ic communities

in terms

of shared beliefs than

by

means

of

the

profes-

sional

relationships

of

their members.

However,

the

easy

way

out

dis-

torts our

understanding

of

science

beyond

all

recognition.

If

we are

to

understand the ongoing process of science, genuine scientific communi-

ties must

be discerned. Sometimes the boundaries between

communities

are not

sharp, they

frequently

change through time,

sometimes

one com-

munity splits into

two,

somewhat more

rarely

two

communities

merge

into

one. All

these complex relations are

certainly difficult to

discern,

but

they are not

only

important

in

their own

right,

they

are crucial

for our

understanding of

what is

going on

at

the

conceptual

level.

The

similarities

between

scientific communities

and

evolving species

might

lead

one

to

suspect that

something

like the type specimen

method

might be

usefully extended to aid

in the

individuation of

groups of

scientists. All one needs to do is to pick a member of a particular

community, any

member, and

attach a name to that

group by means of

this

member.

One

advantage

of

this

method is

that

it

can be used

prior

to

knowing

very much about

the group as

a

group.

It

helps

if

one

picks

a

central

member,

but

such

estimations before

the

fact

tend to be

faulty,

and

the status

of the members of a

group

can

change through time.

A

scientist who was

very

important

initially

can

drop

out

and

a

marginal

member

become

central.

Because organisms

rarely

change

their

species--

for

all

intents and

purposes never--no

temporal index need be

applied

to the

biological

type

specimen. However,

scientists do

join

and

leave

groups. Hence the

sociological

type

specimen must have a

tempor-

al index

appended

to

it,

e.g.,

Hooker in 1859.

In the

history of

science,

sociologically central

members of a

scien-

tific

community

also tend to

be

conceptually

exemplary.

In

spite

of his

relative

isolation in

Down, Darwin was still

sociologically

a

fairly cen-

tral

Darwinian.

Needless

to

say,

he

also made

significant contributions

to

Darwinism,

but even

if

he

had

not,

he would

still

have to be

counted

a Darwinian.

Any

member of

the

group

who was

genuinely

a member

of the

group

can function

as a

type specimen

(a

name bearer) for

the group.

Hooker,

Huxley,

and

Lyell

would all

serve

equally well.

Because

of

his

isolation in

the United

States,

Asa

Gray

would

serve less

well,

while

Henslow was so

peripheral,

he

might

not

even be

counted

a

member.

No-

tice, however: if Henslow is excluded from the Darwinians, it is not

because of his

conceptual

reservations

but because

he

had

ceased to

have

sufficient

contact with the

Darwinians

by

1859 and died

soon thereafter.

Because

communities of

scientists

are sometimes

named by means of the

name

of

a

particular

scientist,

care

must be

taken

not to confuse

social

type specimens

with

eponyms.

When

the

group

is

named after a

patron

saint,

the

distinction

is

easy

enough

to

keep

in

mind.

Mendel was clea-

ly

not

sociologically

a

Mendelian. He

had been

long

dead

when Bateson

picked him as a

patron saint and

eponym for the

Mendelians. All

sorts

of

considerations

go

into

naming

scientific

groups.

sometimes

they are

named

after particular scientists (the Newtonians, Darwinians and Men-

delians),

sometimes

after

places

(the Cold Spring

Harbor

group, the

Columbia

Drosophila

group, the

Texas

group), and sometimes

after

views



12/26

489

they

hold or are believed

to hold

(phrenologists,

uniformitarians,

atom-

ists).

The first

two

ways

of

naming

scientific

communities

pin

them

down

appropriately

to

particular times and

place;

the

latter

does

not

unless

"ideas" are

made

particular

in

a

way

that

conflicts

strongly

with

traditional usage (see later discussion). In any case, the choice of a

particular

scientist

as the

type

specimen

for

a

particular

group

is

in-

dependent

of the

name chosen for the

group.

The

scientist who

serves

to

pin

down

the name

"Darwinians" to the

Darwinians

need

not be

Darwin.

Any

member of

the

group

would do as

well.

As

I

have been

using

the

term"Darwinian"

thus

far,

it refers

to

a

small

group

of

scientists that formed a

tightly

knit

group

during

the

first

decade or so

after the

publication

of

the

Origin.

The

fate

of

this

group

can be

described in

two

ways:

either it

petered

out

as

its

members

died

or lost

interest,

or it

expanded

to

include almost

every-

one working in evolutionary biology. I prefer the first alternative

because

the

"Darwinians" in

the second

sense

was

not

much of a

social

group

(for

a

classic

example

of

a

groups

of

scientists

gradually

dis-

integrating, see

MacLeod

1970).

However,

in

the

last

decade

of

the

century,

something peculiar

happened.

A

new

group

of

scientists e-

merged

who came to

be called

the

"neo-Darwinians".

The

old

guard Dar-

winians

did not

evolve into

this

group;

most

opposed what

they

took to

be

the

excessive

emphasis

placed

by

the

neo-Darwinians

on

selection.

In-

stead,

young scientists

who

were

"Darwinians"

in

only

the

broadest

sense of

the

term

organized

themselves into a

new

scientific

research

group

in

reaction

to

the

work

of

August

Weismann

(Churchill

1968,

1978).

Once

again,

this

group can

be

individuated

by

selecting one of

its

mem-

bers as the type specimen and tracing his professional

relations to oth-

er

members of

the

group.

As

should

be

clear

by

now, the

designation

of

one

member of

a

group

to be

the

type

specimen for

a

group

is not

something

that

the

members

of

that

group do

but is a

device

employed

by

others

studying

the

group.

Because

more

than

one

scholar

is

likely to

study the

same

group

or

groups,

disagreements

are

sure

to

arise.

As

long

as

everyone

keeps

in

mind

that

the

designation of

a

particular

member of a

group

as

the

so-

cial

type

specimen

for that

group

does not

imply

anything

about

the

con-

tributions

of

this

scientist,

one

important

source

for

scholarly

squab-

bling is eliminated. Because the choice of a social type specimen is

arbitrary

with

respect

to

contributions,

considerations

of

priority

are

good

enough

to

settle

disputes

over

who is or

is

not

the

type

specimen

for a

given

group.

I

am

not

saying

that there

will

not be

disagreement

about the

"proper"

name

for

a

group,

but

such

disputes

to

one

side,

whatever

name

is

settled

on

can

be

attached

unequivocally

to

that

group

by the

social

type

specimen.

The

one

implication of

the

type

specimen

method

when

extended to

apply

to

social

groups

that

I

find

disquieting is

the

inflexible

tying

of

a

name

to

the

type

specimen.

For

example,

consider

a

hypothetical

situa-

tion

in

which

the

first

scholar

studying

the

neo-Darwinians

thinks thatC. J. Romanes

(1848-1894) was

a

neo-Darwinian

and

uses him

as the

type

specimen

for

the

neo-Darwinians.

Very

little

research

would be

requimd



13/26

490

to uncover the

mistake.

Nevertheless,

a

rigid

application

of the

type

specimen

method would

require

that

the

name

"neo-Darwinian" be

applied

to Romanes

and his scientific

circle,

not to

such workers

as

Thiselton-

Dyer,E.

R.

Lankester,

and

E. B. Poulton.

Although

such mistakes are

liable to be very rare in intellectual history, the imposition of such

non-standard

terminology by

commentators on science is sure to be re-

sisted and

justifiably

so. It must be admitted that cases in

which

blanket application

of

the

rules of

nomenclature would

require

the

abandonment of a familiar name

are

not unknown

in

biological systemat-

ics.

More time is

spent

at the

periodic meetings

of

the nomenclatural

congresses

hearing appeals

on

such issues

than

on

just

about

any

other

matter.

4.

Conceptual

Systems

Commenting on the reaction to his The Structure of Scientific Revo-

lutions, Kuhn

(1970, p. 187)

remarks

that the "paradigm as shared ex-

ample

is

the

central element

of

what

I

now

take

to

be the most novel

and

least

understood

aspect

of this book." One

of

the

problems

raised

by

Kuhn's book has come to be known as

the

problem

of

incommensurabili-

ty.

If

scientific theories are

tightly-knit

inferential

systems,

if

even observation

statements

are

theory-laden,

and if

the

only

rational

way to choose between

competing theories is

to derive contradictory

observation statements

from

each,

then

theory

choice

in

science

would

seem to be

necessarily

a nonrational

process.

As

Kuhn sees

it, the

chief

misunderstanding

of

his

views

is

the conclusion that scientific

change

is

fundamentally

irrational.

Part

of the

problem

is Kuhn's

habit of equating inference with deductive inference, deductive infer-

ence with

logical,

and

logical

with rational.

Hence, any inference

that is not

deductive

is

neither

logical nor rational.

Certainly

scientific

change

is not

exclusively

a

matter of deductive

inference.

It

is not,

thereby, nonrational, let alone irrational. Rationality is

a much broader notion

than deductive inference.

The novel feature of Kuhn's

system is the

way

he intends to circum-

vent

the problem of

incommensurability by reference to exemplars.

An

exemplar

not

only

solves

the

problems

for

which

it

was formulated but

also serves as a model

or

example

to

"replace

explicit

rules as a

basis

for the solution of the remaining puzzles of normal science." (Kuhn

1970, p. 175).

People

have the

ability

to

extrapolate

from

one puzzle

solution to

another

without

being

able to formulate

any rules that they

might

be

using

to make

these extrapolations.

Kuhn (1977, p. 472) ex-

plicates this

ability

in terms

of a "learned similarity relation". The

example

Kuhn

uses

to

illustrate

this notion

is,

for our

purposes,

un-

fortunate.

It is a

father

teaching

his child

the differences between

swans, geese

and ducks as

they

stroll

through

a

park. As epistemolog-

ically important

as

the similarity relation

may be for inferring gene-

alogy,

I

agree with biologists such as Mayr

and Simpson that theoreti-

cally genealogy is

prior

to

similarity. In spite of this disagreement,

Kuhn's

main

thesis

remains unaffected.

From

the

point

of view

of

evading the problem of incommensurability,



14/26

491

the

important

issue is the

nature

of this

similarity

relation.

If

it

can

be

expressed

linguistically,

then

Kuhn is

right

back

where

he

started. The words

used

to

express

the

similarity

relation

that

ob-

tains between an

exemplar

and its

exemplifications

are as liable

to

be

as theory-laden as any others. If this relation cannot be expressed

linguistically,

then

its

status

remains

problematic.

It is

one

thing

to

argue

that a

particular

way

of

reasoning

is not

adequately captured

by

current formal

analyses

of inference.

It

is

quite

another

to

argue

that it is

ineluctably

ineffable. If

biological

species

really

were

classes

of similar

organisms

(ancestor-descendant

relations

be

damned),

current methods of

multivariate

analysis

can

capture

these

correlations

well

enough. There

is

nothing

ineffable here.

Problems arise

chiefly

when

one

attempts

to

combine

genealogy

with

similarity.

I

am not sure

that Kuhnian

exemplars

can be used to

avoid

the

prob-

lem of

incommensurability (Suppe 1977). I propose to present quite a

different

use for

exemplars--as

type

specimens

for the

individuation

of

conceptual

systems.

To

perform

the function

assigned

them

by

Kuhn,

exemplars

must

be both

exemplary

and

similar

to

their

exemplifications.

For

example,

a

good

case

can

be made that

Mendel's

way

of

structuring

breeding

experiments served as a

Kuhnian

exemplar

for

modern

genetics.

Most of

the

early

progress

in

genetics was the

result

of

geneticists

milking Mendel's

exemplar

for

all it

was worth.

However,

problems

arise.

This

same

exemplar can be found in

the works of

other

geneticists

before

anyone heard of

Mendel.

In

many

instances,

it

was

these

characteriza-

tions

that

served

as

Kuhnian

exemplars.

As it

turns

out,

legends

such

as

Darwin's

finches

are often

effective

Kuhnian

exemplars,

as

effective

as more historically accurate examples. To complicate matters further,

later

applications of

an

examplar

may

have

very

little

in

common

with

earlier

applications.

To

serve as a

conceptual

type

specimen,

as a

fixed

reference point

by

which

a

name can

be

attached

to a

conceptual

system, an

exemplar

need

not be

especially

exemplary, nor

need

it be

in

any

sense

similar

to

other

elements in

its

conceptual

system.

However,

it

must be

a

good

deal

more

concrete than

KuhnI's

puzzle

solutions. I

am

not

sure

whether

those

philosophers who

have

suggested

treating

conceptual

systems

as

historical

entities

are

completely aware of

the

magnitude of

the

change

that they are suggesting. I suspect, as in the case of biology, rem-

nants

of

the

traditional view

remain.

Concepts are

commonly

treated as

atemporal

similarity

classes,

as

expression

types.

Two

instances

of a

particular

concept

(two

expression

tokens)

are

instances of

the

same

concept

if,

and

only

if

in

some

sense,

they

mean

the same

thing.

A

decade or

so

ago,

Kripke

(1972)

and

Putnam

(1973,

1975)

caused

quite

a

stir

by

suggesting

that

singular

terms

(in

particular

proper

names) and

some

substance

and

kind

terms

might

best be

interpreted

as

rigid

designators. In

rigid

designation, a

name

is

conferred in

an

initial

baptismal

act

(possibly

fictitious)

and

thereafter

passed

on in

a

link-to-link

reference

preserving

chain.

Regardless

of the

appro-

priateness of the Kripke-Putnam analysis in general, it accurately de-

picts

the

way in

which

systematists

introduce

the

names of

biological



15/26

492

taxa. The baptismal

act

in

systematics

is not identical in

every respect

to that practiced by

Judeo-Christians

(e.g.,

no water is

involved),

but

it is easily as ritualized and never fictitious.

Both also

require

ref-

erence preservation. The respective terms

cannot

change

their

reference,

although we can find out that we are mistaken about what we thought

their reference was.

The interesting thing about the Kripke-Putnam

analysis is that it is

applied

to

certain

general

terms

(such

as

'tiger')

as well as

traditicn-

al proper names (such

as

'Moses').

If

Iwere

arguing

that the names of

particular species

are

general

terms and species themselves kinds of

some

sort,

the

coincidence of taxonomic

practice

with the

procedures

postulated by Kripke

and Putnam

might

serve as

indirect

support

for

their

views.

However,

because

my

main

contention

is that

species

are

not

kinds

and their names not

general,

the position

I

am

arguing has,

in

this connection, no implications

for

the Kripke-Putnam

analysis of rigid

designation. The names of particular species, as are the names of all

spatiotemporally localized individuals, proper.

That

proper

names are

rigid designators should surprise no one.

The interesting feature of

the

Kripke-Putnam analysis

for our

purposes

is

that the link-to-link

reference preserving

chains are themselves historical entities tied

down

to a particular time and place. No use of

a

term not causally connected

to the original baptismal act can be part of

this chain.

The

main

weakness

of the

Kripke-Putnam

analysis

for

my purpose is

that

it

must be reference

preserving. Species

do

evolve even

if

the

link-to-link reference preserving

chains do

not.

However,

I

see no

reason not to let these chains themselves "evolve". Kitcher (1978) sets

out a

way

in

which it

is

"possible

for

scientists

to

use different

to-

kens

of

the same expression-type

to

refer

to different entities."

(Kitcher 1978, p. 536).

He does so

by

means of postulating a community-

based reference

potential

for

each

expression-type.

The reference

po-

tential of

an

expression-type

for a

particular

community is the "set of

events such

that

production

of

tokens

of that

type by

members of the

community are normally instituted by

an

event

in

the associated set."

(Kitcher 1978, p. 540).

Because

socially

defined

communities of

scien-

tists

are to some extent heterogeneous,

the reference potential of an

expression-type

is also liable to be somewhat variable

at

any

one

point

in

time. Because the

make-up

of scientific

communities changes through

time,

the referential

potential

for

particular

expression-types

is

also

likely

to

change through

time.

I

think that what is needed

in

addition

to

a semantic analysis of

reference such as the one presented by Kitcher, is

a

general analysis of

conceptual systems that is

not

designed

to solve traditional semantic

problems such as meaning change

but

merely provides

criteria

for

indi-

viduating conceptual systems

as historical entities. The purpose of

this

section is

to

present just such

an

analysis.

On

the basis

of

the

biological analog,

four conditions seem necessary:

(1) descent is necessary: conceptual replication sequences and the

systems

which

they

form

must be historical

entities;



16/26

493

(2)

local retention of information

content

in

replication

sequences

is

necessary,

but

global

change

must also

be

possible;

(3) different

replication

sequences

must co-exist

in the same

con-

ceptual

system;

(4)

the relations

that

integrate

the elements

of a

conceptual

system

into a

system

include but cannot

be limited

just

to inferential

rela-

tions.

I do not intend to

deny

that there

is some

point

in

recognizing

to-

tally unrestricted reference

types, e.g.,

3 to

1

ratios in

hereditary

patterns.

Literally

hundreds of

investigators

can

be found

who

stumbled

upon

such

3 to

1

ratios

(including

Darwin).

The lists of

precursors

that historians can

produce

for

any

"unit

idea" or "theme" in

science

are

fascinating'.

These lists are sometimes

disparaged

because some of

the

items on a

particular

list are

really

not similar

enough

to

count as

being the same idea. This is not my complaint at all. My complaint is

that

concepts

in

this

sense

do not

function

in

conceptual

systems

as

historical

entities.

Paying

attention

to

the filiation of

ideas is not

just good

historiography--which

it is--it

is

necessary

if

conceptual

change

is to

be

interpreted

as a

matter of the

replication,

competition,

and

selective retention of

ideas.

All

three of

these notions

apply

only

to concrete

exemplifications--tokens--and not

types.

To

put

it meta-

phorically, there is no

replication

at a

distance.

Conceptual

tokens

must be

organized

into

more

inclusive

entities,

but

these

entities are

not

those

of

traditional

semantic

categories. Instead

they

are

replica-

tion

sequences.

One

might well

argue that

Lamarck's notion

of

the

transmutation of

species was

replicated

in

Darwin's

theory

of

evolution

because Darwin

was at

least aware of

Lamarck's

views as

Lyell

presented

them

in

his

Principles

of

Geology

(1830-3),

but

one cannot

claim

that

Darwin

was

replicating

the

transmutationist views of

Pierre-Jean

Cabanis

(1757-

1808)

if no

chain of

influence can be

traced from

Cabanis

to

Darwin

(Richards

1982).

Local

retention of

assertive

content is

necessary for

tokens

to

be

part

of

the

same

replication

sequence, but it

is

far from

sufficient.

Matthew's

(1831) statement of

natural

selection

was

nearly

identical to

that of

Darwin, but

it

does not

belong in

Darwinism

as an

historical

entity

because no

one seems

to

have noticed

it

or have

been

influenced by it. The point is not assigning credit for originality

but

gauging effect.

Truly

unappreciated

precursors do

not

count.

Matthew was not

sociologically a

Darwinian.

Matthew's

views, as

similar

as

they

might

have

been to

those

of

Darwin,

also do

not

belong in Dar-

winism.

If

tokens of

a

particular idea

are

to build up

differentially

in a

conceptual

system,

local

similarity is

necessary.

Ideas

must be

trans-

mitted

with

some

fidelity.

However,

long

term change

must

also be

pos-

sible.

For

example, all

but

one

of

the

"laws" usually

associated

with

Mendel's name

at

the turn of

the

century

underwent rapid

and

signifi-

cant change, butthey belong in the same replication sequence because

they

are

modifications

of previous

tokens.

Conversely,

Goldschmidt's



17/26

494

(1940) systemic

mutations

do not

belong

in

Darwinism even

though quite

similar ideas introduced

thirty years

later

may (Gould 1982).

Local similarity

is relevant

only

for

conceptual replication

se-

quences.

Numerous

ideas

coexist

in

the

same

conceptual system

even

if

they are quite different. For

example,

Darwin's views on evolution

were quite

different from

his

views on heredity.

In

his

own

version

of

Darwinism, they

coexisted.

In

other

versions they

did not.

Pangenesis

was only one

very

minor

strain

in

the larger

conceptual system.

One

is

tempted to

interpret

the

relations between

the several elements

in

a

conceptual system

in

terms of

inference,

and

inferences

do

play

a role

in

integrating

some

of the

elements of a conceptual system into a single

system.

As Toulmin

(1972) puts it, there are at least "pockets

of

sys-

tematicity"

in

scientific

disciplines.

However, the only inferential

relations

that

belong

in a

system are the ones

actually

made at the time.

Unnoticed though perfectly valid conclusions do not. Similarly, a well

known property of contradictions

is

that

they imply any proposition

whatsoever. Time and

again,

later workers have uncovered contradictions

in

early formulations of particular scientific

theories,

but as

long

as

these contradictions were not exploited, no

damage

was

done.

The

only

inferences

exemplars and scientific change author(s): david l. hullsource: psa: proceedings of the biennial...

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