The Sleepwalkers (250 page)

This
is
a
very
curious
paradox
indeed.
The
senses
and
organs
of
all
species
evolve
(
via
mutation
and
selection
as
we
suppose),
according
to
adaptative
needs;
and
novelties
in
anatomical
structure
are
by
and
large
determined
by
those
needs.
Nature
meets
its
customers'
requirements
by
providing
longer
necks
to
graze
off
the
top
of
trees,
harder
hooves
and
teeth
to
cope
with
the
coarse
grass
of
the
drying
steppes;
by
shrinking
the
smellbrain
and
enlarging
the
visual
cortex
of
birds,
arboreals,
and
bipeds
as
they
slowly
raise
their
heads
above
ground.
But
it
is
entirely
unprecedented
that
nature
should
endow
a
species
with
an
extremely
complex
luxury
organ
far
exceeding
its
actual
and
immediate
needs,
which
the
species
will
take
millennia
to
learn
to
put
to
proper
use
–
if
it
ever
does.
Evolution
is
supposed
to
cater
for
adaptative
demands;
in
this
case
the
goods
delivered
anticipated
the
demand
by
a
time-stretch
of
geological
magnitude.
The
habits
and
learning
potentialities
of
all
species
are
fixed
within
the
narrow
limits
which
the
structure
of
its
nervous
system
and
organs
permits;
those
of
homo
sapiens
seem
unlimited
precisely
because
the
possible
uses
of
that
evolutionary
novelty
in
his
skull
were
quite
out
of
proportion
with
the
demands
of
his
natural
environment.

Since
evolutionary
genetics
is
unable
to
account
for
the
fact
that
a
biologically
more
or
less
stable
race
should
mentally
evolve
from
cave-dwellers
to
spacemen,
we
can
only
conclude
that
the
term
"mental
evolution"
is
more
than
a
metaphor;
and
that
it
refers
to
a
process
in
which
some
factors
operate
to
which
as
yet
we
have
not
got
a
clue.
All
we
know
is
that
mental
evolution
cannot
be
understood
either
as
a
cumulative,
linear
process,
or
as
a
case
of
"organic
growth"
comparable
to
the
maturing
of
the
individual;
and
that
it
would
perhaps
be
better
to
consider
it
in
the
light
of
biological
evolution,
of
which
it
is
a
continuation.

It
would
indeed
seem
more
expedient
to
treat
the
history
of
thought
in
terms
borrowed
from
biology
(even
if
they
can
yield
no
more
than
analogies)
than
in
terms
of
an
arithmetical
progression.
"Intellectual
progress"
has,
as
it
were,
linear
associations
–
a
continuous
curve,
a
steadily
rising
water
level;
whereas
"evolution"
is
known
to
be
a
wasteful,
fumbling
process
characterized
by
sudden
mutations
of
unknown
cause,
by
the
slow
grinding
of
selection,
and
by
the
dead-ends
of
overspecialization
and
rigid
inadaptability.
"Progress"
can
by
definition
never
go
wrong;
evolution
constantly
does;
and
so
does
the
evolution
of
ideas,
including
those
of
"exact
science".
New
ideas
are
thrown
up
spontaneously
like
mutations;
the
vast
majority
of
them
are
useless
crank
theories,
the
equivalent
of
biological
freaks
without
survival-value.
There
is
a
constant
struggle
for
survival
between
competing
theories
in
every
branch
of
the
history
of
thought.
The
process
of
"natural
selection",
too,
has
its
equivalent
in
mental
evolution:
among
the
multitude
of
new
concepts
which
emerge
only
those
survive
which
are
well
adapted
to
the
period's
intellectual
milieu
.
A
new
theoretical
concept
will
live
or
die
according
to
whether
it
can
come
to
terms
with
this
environment;
its
survival
value
depends
on
its
capacity
to
yield
results.
When
we
call
ideas
"fertile"
or
"sterile",
we
are
unconsciously
guided
by
biological
analogy.
The
struggle
between
the
Ptolemaic,
Tychonic
and
Copernican
systems,
or
between
the
Cartesian
and
Newtonian
views
of
gravity,
was
decided
by
those
criteria.
Moreover,
we
find
in
the
history
of
ideas
mutations
which
do
not
seem
to
correspond
to
any
obvious
need,
and
at
first
sight
appear
as
mere
playful
whimsies
–
such
as
Appollonius'
work
on
conic
sections,
or
the
non-Euclidian
geometries,
whose
practical
value
became
apparent
only
later.
Conversely,
there
are
organs
which
have
lost
their
purpose
and
are
yet
carried
over
as
an
evolutionary
legacy:
modern
science
is
full
of
appendices
and
rudimentary
monkey-tails.

There
occur
in
biological
evolution
periods
of
crisis
and
transition
when
there
is
a
rapid,
almost
explosive
branching
out
in
all
directions,
often
resulting
in
a
radical
change
in
the
dominant
trend
of
development.
The
same
kind
of
thing
seems
to
have
happened
in
the
evolution
of
thought
at
critical
periods
like
the
sixth
century
B.C.
or
the
seventeenth
A.D.
After
these
stages
of
"adaptative
radiations",
when
the
species
is
plastic
and
malleable,
there
usually
follow
periods
of
stabilization
and
specialization
along
the
new
lines
–
which
again
often
lead
into
dead
ends
of
rigid
over-specialization.
When
we
look
back
at
the
grotesque
decline
of
Aristotelian
scholasticism,
or
the
blinkered
singlemindedness
of
Ptolemaic
astronomy,
we
are
reminded
of
the
fate
of
those
"orthodox"
marsupials,
like
the
koala,
who
changed
from
tree-climbers
into
tree-clingers.
Their
hands
and
feet
turned
into
hooks,
their
fingers
no
longer
served
to
pluck
fruit
and
explore
objects
but
degenerated
into
curved
claws
with
the
sole
purpose
of
fixing
the
animal
to
the
bark
of
the
tree
to
which
it
hangs
on
for
dear
life.