The Sleepwalkers (149 page)

"What
matters
to
me,"
Kepler
explained
in
his
Preface,
"is
not
merely
to
impart
to
the
reader
what
I
have
to
say,
but
above
all
to
convey
to
him
the
reasons,
subterfuges,
and
lucky
hazards
which
led
me
to
my
discoveries.
When
Christopher
Colombus,
Magelhaen
and
the
Portuguese
relate
how
they
went
astray
on
their
journeys,
we
not
only
forgive
them,
but
would
regret
to
miss
their
narration
because
without
it
the
whole,
grand
entertainment
would
be
lost.
Hence
I
shall
not
be
blamed
if,
prompted
by
the
same
affection
for
the
reader,
I
follow
the
same
method."
^1a

Before
embarking
on
the
story,
it
will
be
prudent
to
add
my
own
apology
to
Kepler's.
Prompted
by
the
same
"affection
for
the
reader"
I
have
tried
to
simplify
as
far
as
possible
a
difficult
subject:
even
so,
the
present
chapter
must
of
necessity
be
slightly
more
technical
than
the
rest
of
this
book.
If
some
passages
tax
his
patience,
even
if
occasionally
he
fails
to
grasp
a
point
or
loses
the
thread,
he
will,
I
hope,
nevertheless
get
a
general
idea
of
Kepler's
odyssey
of
thought,
which
opened
up
the
modern
universe.

2.
Opening Gambits

It
will
be
remembered
that
at
the
partitioning
of
the
cosmos
which
followed
young
Kepler's
arrival
at
Benatek
Castle,
he
was
allotted
the
study
of
the
motions
of
Mars
which
had
defeated
Tycho's
senior
assistant,
Longomontanus,
and
Tycho
himself.

"I
believe
it
was
an
act
of
Divine
Providence,"
he
commented
later
on,
"that
I
arrived
just
at
the
time
when
Longomontanus
was
occupied
with
Mars.
For
Mars
alone
enables
us
to
penetrate
the
secrets
of
astronomy
which
otherwise
would
remain
forever
hidden
from
us."
2

The
reason
for
this
key
position
of
Mars
is
that,
among
the
outer
planets,
his
orbit
deviates
more
than
the
others'
from
the
circle;
it
is
the
most
pronouncedly
elliptical.
It
was
precisely
for
that
reason
that
Mars
had
defied
Tycho
and
his
assistant:
since
they
expected
the
planets
to
move
in
circles,
it
was
impossible
to
reconcile
theory
with
observation:

"He
[Mars]
is
the
mighty
victor
over
human
inquisitiveness,
who
made
a
mockery
of
all
the
stratagems
of
astronomers,
wrecked
their
tools,
defeated
their
hosts;
thus
did
he
keep
the
secret
of
his
rule
safe
throughout
all
past
centuries
and
pursued
his
course
in
unrestrained
freedom;
wherefore
that
most
famous
of
Latins,
the
priest
of
nature
Pliny,
specially
indicted
him:
MARS
IS
A
STAR
WHO
DEFIES
OBSERVATION."
³

Thus
Kepler,
in
his
dedication
of
the
New
Astronomy
to
the
Emperor
Rudolph
II.
The
dedication
is
written
in
the
form
of
an
allegory
of
Kepler's
war
against
Mars,
begun
under
"Tycho's
supreme
command",
patiently
pursued
in
spite
of
the
warning
example
of
Rheticus
who
went
off
his
head
over
Mars,
in
spite
of
other
dangers
and
terrible
handicaps,
such
as
a
lack
of
supplies
owing
to
Rudolph's
failure
to
pay
Kepler's
salary
–
and
so
on
to
the
triumphant
end
when
the
Imperial
Mathematicus,
riding
a
chariot,
leads
the
captive
enemy
to
the
Emperor's
throne.

Thus
Mars
held
the
secret
of
all
planetary
motion,
and
young
Kepler
was
assigned
the
task
of
solving
it.
He
first
attacked
the
problem
on
traditional
lines;
when
he
failed,
he
began
to
throw
out
ballast
and
continued
doing
so
until,
by
and
by,
he
got
rid
of
the
whole
load
of
ancient
beliefs
on
the
nature
of
the
universe,
and
replaced
it
by
a
new
science.

As
a
preliminary,
he
made
three
revolutionary
innovations
to
gain
elbow
room,
as
it
were,
for
tackling
his
problem.
It
will
be
remembered
that
the
centre
of
Copernicus'
system
was
not
the
sun,
but
the
centre
of
the
earth's
orbit;
and
that
already
in
the
Mysterium
Cosmographicum
Kepler
had
objected
to
this
assumption
as
physically
absurd.
Since
the
force
which
moved
the
planets
emanated
from
the
sun,
the
whole
system
should
be
centred
on
the
body
of
the
sun
itself.
⁴