The Sleepwalkers (211 page)

Throughout
the
document
Galileo
completely
evaded
any
astronomical
or
physical
discussion
of
the
Copernican
system;
he
simply
gave
the
impression
that
it
was
proven
beyond
doubt.
If
he
had
talked
to
the
point,
instead
of
around
it,
he
would
have
had
to
admit
that
Copernicus'
forty-odd
epicycles
and
eccentrics
were
not
only
not
proven
but
a
physical
impossibility,
a
geometrical
device
and
nothing
else;
that
the
absence
of
an
annual
parallax,
i.e.
of
any
apparent
shift
in
the
position
of
the
fixed
stars,
in
spite
of
the
new
telescopic
precision,
weighed
heavily
against
Copernicus;
that
the
phases
of
Venus
disproved
Ptolemy,
but
not
Herakleides
or
Tycho;
and
that
all
he
could
claim
for
the
Copernican
hypothesis
was
that
it
described
certain
phenomena
(the
retrogression)
more
economically
than
Ptolemy;
as
against
this,
the
abovementioned
physical
objections
would
have
carried
the
day.

For
it
must
be
remembered
that
the
system
which
Galileo
advocated
was
the
orthodox
Copernican
system,
designed
by
the
Canon
himself,
nearly
a
century
before
Kepler
threw
out
the
epicycles
and
transformed
the
abstruse
paper-construction
into
a
workable
mechanical
model.
Incapable
of
acknowledging
that
any
of
his
contemporaries
had
a
share
in
the
progress
of
astronomy,
Galileo
blindly
and
indeed
suicidally
ignored
Kepler's
work
to
the
end,
persisting
in
the
futile
attempt
to
bludgeon
the
world
into
accepting
a
Ferris
wheel
with
forty-eight
epicycles
as
"rigorously
demonstrated"
physical
reality.

What
was
the
motive
behind
it?
For
almost
fifty
years
of
his
life,
he
had
held
his
tongue
about
Copernicus,
not
out
of
fear
to
be
burnt
at
the
stake,
but
to
avoid
academic
unpopularity.
When,
carried
away
by
sudden
fame,
he
had
at
last
committed
himself,
it
became
at
once
a
matter
of
prestige
to
him.
He
had
said
that
Copernicus
was
right,
and
whosoever
said
otherwise
was
belittling
his
authority
as
the
foremost
scholar
of
his
time.
That
this
was
the
central
motivation
of
Galileo's
fight
will
become
increasingly
evident.
It
does
not
exonerate
his
opponents;
but
it
is
relevant
to
the
problem
whether
the
conflict
was
historically
inevitable
or
not.

The
final
section
of
the
Letter
to
the
Grand
Duchess
is
devoted
to
the
miracle
of
Joshua.
Galileo
first
explains
that
the
sun's
rotation
around
its
axis
is
the
cause
of
all
planetary
motion.
"And
just
as
if
the
motion
of
the
heart
should
cease
in
an
animal,
all
other
motions
of
its
members
would
also
cease,
so
if
the
rotation
of
the
sun
were
to
stop,
the
rotations
of
all
the
planets
would
stop
too."
¹⁸
Thus
he
not
only
assumed,
with
Kepler,
the
annual
revolutions
of
the
planets
to
be
caused
by
the
sun,
but
also
their
daily
rotation
round
their
axes
–
an
ad
hoc
hypothesis
with
no
more
"rigorous
proof"
than
the
analogy
with
the
animal's
heart.
He
then
concludes
that
when
Joshua
cried:
"Sun,
stand
thou
still,"
the
sun
stopped
rotating,
and
the
earth
in
consequence
stopped
both
its
annual
and
daily
motion.
But
Galileo,
who
came
so
close
to
discovering
the
law
of
inertia,
knew
better
than
anybody
that
if
the
earth
suddenly
stopped
dead
in
its
track,
mountains
and
cities
would
collapse
like
match-boxes;
and
even
the
most
ignorant
monk,
who
knew
nothing
about
impetus,
knew
what
happened
when
the
horses
reared
and
the
mail-coach
came
to
a
sudden
halt,
or
when
a
ship
ran
against
a
rock.
If
the
Bible
was
interpreted
according
to
Ptolemy,
the
sudden
stand-still
of
the
sun
would
have
no
appreciable
physical
effect,
and
the
miracle
remained
credible
as
miracles
go;
if
it
was
interpreted
according
to
Galileo,
Joshua
would
have
destroyed
not
only
the
Philistines,
but
the
whole
earth.
That
Galileo
hoped
to
get
away
with
this
kind
of
painful
nonsense,
showed
his
contempt
for
the
intelligence
of
his
opponents.

In
the
Letter
to
the
Grand
Duchess
Christina
the
whole
tragedy
of
Galileo
is
epitomized.
Passages
which
are
classics
of
didactic
prose,
superb
formulations
in
defence
of
the
freedom
of
thought,
alternate
with
sophistry,
evasion
and
plain
dishonesty.