The Sleepwalkers (159 page)

With
his usual disarming frankness, he confessed what had happened:

"Why
should
I
mince
my
words?
The
truth
of
Nature,
which
I
had
rejected
and
chased
away,
returned
by
stealth
through
the
backdoor,
disguising
itself
to
be
accepted.
That
is
to
say,
I
laid
[the
original
equation]
aside,
and
fell
back
on
ellipses,
believing
that
this
was
a
quite
different
hypothesis,
whereas
the
two,
as
I
shall
prove
in
the
next
chapter,
are
one
and
the
same
...
I
thought
and
searched,
until
I
went
nearly
mad,
for
a
reason
why
the
planet
preferred
an
elliptical
orbit
[to
mine]...
Ah,
what
a
foolish
bird
I
have
been!"
³²

But
in the List of Contents, in which he gives a brief outline of the
whole work, Kepler sums up the matter in a single sentence:

"I
show
[in
this
chapter]
how
I
unconsciously
repair
my
error."

The
remainder
of
the
book
is
in
the
nature
of
a
mopping-up
operation
after
the
final
victory.

8.
Some Conclusions

It
was
indeed
a
tremendous
victory.
The
great
Ferris
wheel
of
human
delusion,
with
its
celestial
catwalks
for
the
wandering
planets,
this
phantasmagoria
which
had
blocked
man's
approach
to
nature
for
two
thousand
years,
was
destroyed,
"banished
to
the
lumber-room".
Some
of
the
greatest
discoveries,
as
we
saw,
consist
mainly
in
the
clearing
away
of
psychological
road-blocks
which
obstruct
the
approach
to
reality;
which
is
why,
post
factum
,
they
appear
so
obvious.
In
a
letter
to
Longomontanus,
³³
Kepler
qualified
his
own
achievement
as
the
"cleansing
of
the
Augean
stables".

But
Kepler
not
only
destroyed
the
antique
edifice;
he
erected
a
new
one
in
its
place.
His
Laws
are
not
of
the
type
which
appear
self-evident,
even
in
retrospect
(as,
say,
the
Law
of
Inertia
appears
to
us);
the
elliptic
orbits
and
the
equations
governing
planetary
velocities
strike
us
as
"constructions"
rather
than
"discoveries".
In
fact,
they
make
sense
only
in
the
light
of
Newtonian
Mechanics.
From
Kepler's
point
of
view,
they
did
not
make
much
sense;
he
saw
no
logical
reason
why
the
orbit
should
be
an
ellipse
instead
of
an
egg.
Accordingly,
he
was
more
proud
of
his
five
perfect
solids
than
of
his
Laws;
and
his
contemporaries,
including
Galileo,
were
equally
incapable
of
recognizing
their
significance.
The
Keplerian
discoveries
were
not
of
the
kind
which
are
"in
the
air"
of
a
period,
and
which
are
usually
made
by
several
people
independently;
they
were
quite
exceptional
one-man
achievements.
That
is
why
the
way
he
arrived
at
them
is
particularly
interesting.

I
have
tried
to
re-trace
the
tortuous
progress
of
his
thought.
Perhaps
the
most
astonishing
thing
about
it
is
the
mixture
of
cleanness
and
uncleanness
in
his
method.
On
the
one
hand,
he
throws
away
a
cherished
theory,
the
result
of
years
of
labour,
because
of
those
wretched
eight
minutes
of
arc.
On
the
other
hand
he
makes
impermissible
generalizations,
knows
that
they
are
impermissible,
yet
does
not
care.
And
he
has
a
philosophical
justification
for
both
attitudes.
We
heard
him
sermonising
about
the
duty
to
stick
rigorously
to
observed
fact.
But
on
the
other
hand
he
says
that
Copernicus
"sets
an
example
for
others
by
his
contempt
for
the
small
blemishes
in
expounding
his
wonderful
discoveries.
If
this
had
not
been
always
the
usage,
then
Ptolemy
would
never
have
been
able
to
publish
his
Almagest
,
Copernicus
his
Revolutions
,
and
Reinhold
his
Prutenian
Tables...
It
is
not
surprising
that,
when
he
dissects
the
universe
with
a
lancet,
various
matters
emerge
only
in
a
rough
manner."
³⁴

Both
precepts
have,
of
course,
their
uses.
The
problem
is
to
know
when
to
follow
one,
when
the
other.
Copernicus
had
a
one-track
mind;
he
never
flew
off
at
a
tangent;
even
his
cheatings
were
heavy-handed.
Tycho
was
a
giant
as
an
observer,
but
nothing
else.
His
leanings
toward
alchemy
and
astrology
never
fused,
as
in
Kepler,
with
his
science.
The
measure
of
Kepler's
genius
is
the
intensity
of
his
contradictions,
and
the
use
he
made
of
them.
We
saw
him
plod,
with
infinite
patience,
along
dreary
stretches
of
trial-and-error
procedure,
then
suddenly
become
airborne
when
a
lucky
guess
or
hazard
presented
him
with
an
opportunity.
What
enabled
him
to
recognize
instantly
his
chance
when
the
number
0.00429
turned
up
in
an
unexpected
context
was
the
fact
that
not
only
his
waking
mind,
but
his
sleepwalking
unconscious
self
was
saturated
with
every
conceivable
aspect
of
his
problem,
not
only
with
the
numerical
data
and
ratios,
but
also
with
an
intuitive
"feel"
of
the
physical
forces,
and
of
the
Gestalt
configurations
which
it
involved.
A
locksmith
who
opens
a
complicated
lock
with
a
crude
piece
of
bent
wire
is
not
guided
by
logic,
but
by
the
unconscious
residue
of
countless
past
experiences
with
locks,
which
lend
his
touch
a
wisdom
that
his
reason
does
not
possess.
It
is
perhaps
this
intermittent
flicker
of
an
overall
vision
which
accounts
for
the
mutually
compensatory
nature
of
Kepler's
mistakes,
as
if
some
balancing
reflex
or
"backfeed"
mechanism
had
been
at
work
in
his
unconscious
mind.