The Sleepwalkers (232 page)

"Hearken
then
to
this
great
and
new
wonder.
The
first
discoverer
of
the
solar
spots,
as
also
of
all
other
celestial
novelties,
was
our
Lincean
academician,
and
he
discovered
them
anno
1610..."
¹⁸

The
"Lincean
academician"
is
the
expression
by
which
the
Galileo
in
the
Dialogue
refers
to
himself.

After
thus
reasserting
his
spurious
claim,
he
proceeds
to
claim
another
discovery
of
Scheiner's:
that
the
sun,
and
with
it
the
spots,
rotate
on
an
axis
which
is
tilted
against
the
plane
of
the
ecliptic.
As
a
result
of
this,
the
spots
also
travel
round
the
sun
in
"tilted"
circles
(as
seen
from
the
earth);
and
their
curve
changes
according
to
the
earth's
position
–
just
as
the
curvature
of
a
tilted
spinning
top
changes
to
the
eye
as
we
walk
around
it.
Ergo,
Galileo
concludes,
the
changing
curves
along
which
the
sunspots
travel
prove,
in
a
manner
"so
solid
and
rational
as
never
before",
that
the
earth
moves
round
the
sun.
¹⁹

At
this
point
poor
Simplicius
turns
into
a
relativist
and
correctly
observes
that
the
curves
of
the
spots
would
look
just
the
same
whether
the
sun
travelled
round
the
earth
or
the
earth
round
the
sun.
Salviati
proceeds
to
demolish
this
objection:
if
we
assume
that
the
sun
travels
round
the
earth,
the
spots
will
look
the
same
only
if
we
also
assume
that
the
sun's
axis
always
remains
parallel
to
itself;
and
this
he
finds
"
very
hard
and
almost
impossible
to
believe
".
²⁰
Simplicius,
intimidated,
pipes
down;
Sagredo
exclaims
"that
amongst
all
the
ingenious
subtleties
I
ever
heard,
I
have
never
met
with
anything
of
greater
admiration
to
my
intellect
or
that
has
more
absolutely
captivated
my
judgement."
²¹

One
simply
gapes.
Salviati
wins
his
case
by
pretending
that
it
was
virtually
impossible
for
one
heavenly
body
to
travel
round
another
while
its
axis
remains
parallel
to
itself.
Yet
that
is,
of
course,
what
the
earth
does
while
travelling
round
the
sun:
its
axis
remains
parallel
to
itself
at
a
constant
tilt
of
23
1/2
degrees.
If
it
was
impossible
to
believe
that
the
sun
could
move
thus,
then
it
was
equally
impossible
that
the
earth
should
move
thus.
Yet
in
a
later
section
Galileo
discusses
at
great
length
the
reasons
why
the
earth
moves
thus,
and
explains
that
the
preservation
of
the
fixed
tilt
of
its
axis
"is
far
from
having
any
repugnance
or
difficulty
in
it."
²²

The
changing
faces
of
the
sunspot-paths
were
as
obvious
a
consequence
of
the
tilt
in
the
sun's
axis
as
the
changing
seasons
are
a
consequence
of
the
tilt
in
the
earth's
axis.
It
was
as
simple
as
that.
But
the
two
pages
in
which
Galileo
argues
the
point
against
Simplicius
²³
are
among
the
most
obscure
and
incomprehensible
in
the
book.
He
employs
his
usual
tactics
of
refuting
his
opponent's
thesis
without
proving
his
own;
in
this
case
not
by
sarcasm,
but
by
confusing
the
issue.

There
can
be
no
doubt
that
Galileo's
theory
of
the
tides
was
based
on
unconscious
self-deception;
but
in
the
light
of
the
above
there
can
also
be
little
doubt
that
the
sunspot
argument
was
a
deliberate
attempt
to
confuse
and
mislead.
To
represent
the
constant
tilt
of
a
rotating
body
as
a
new
and
inconceivable
hypothesis,
when
every
student
since
Pythagoras
knew
that
this
was
the
reason
why
summer
followed
winter;
to
obscure
this
simple
issue
by
the
novelty
of
curving
sunspots,
while
making
the
complexities
of
Copernicus
appear
deceptively
simple,
was
part
of
a
deliberate
strategy,
based
on
Galileo's
contempt
for
the
intelligence
of
his
contemporaries.
We
have
seen
that
scholars
have
always
been
prone
to
manias
and
obsessions,
and
inclined
to
cheat
about
details;
but
impostures
like
Galileo's
are
rare
in
the
annals
of
science.

The
fourth
and
last
day
of
the
Dialogue
is
taken
up
almost
entirely
by
the
theory
of
the
tides,
which
is
elaborated
in
more
detail.
The
annual
variations
in
the
tides
are
explained
by
the
tilt
of
the
earth's
axis,
the
monthly
variations
by
monthly
changes
in
orbital
velocity.
²⁴
Kepler's
explanation
of
the
tides
by
the
moon's
attraction
is
rejected
with
the
remark
that
"despite
his
open
and
penetrating
mind"
he
has
"lent
his
ear
and
his
assent
to
the
moon's
dominion
over
the
waters,
to
occult
properties
[gravity]
and
such-like
little
fancies."
^24a