Bīrūnī, Muḥammad ibn Aḥmad, Alberuni's India (v. 1)

(London :  Kegan Paul, Trench, Trübner & Co.,  1910.)

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226
 

ALBERUNPS INDIA.
 

Aristotle,
Ptolemy,
Johannes
Grammati¬
cus.
 

that each moving body is brought into motion by some¬
thing moving which is not within itself. So also this
ninth sphere would presuppose a mover outside itself.
What, however, should prevent this mover from putting
the eight spheres into motion without the intermedia¬
tion of a ninth sphere ?

As regards the representatives of the second view,
one might almost think that they had a knowledge of
the words of Aristotle which we have quoted, and that
they knew that the first mover is motionless, for they
represent the ninth sphere as motionless and as the
source of the east to west rotation. However, Aristotle
has also proved that the first mover is not a body,
whilst he must be a body, if they describe him as a
globe, as a sphere, and as comprehending something
else within itself and motionless.

Thus the theory of the ninth sphere is proved to be
an impossibility. To the same effect are the words of
Ptolemy in the preface of his Almagest: " The first
cause of the first motion of the universe, if we consider
the motion by itself, is according to our opinion an in¬
visible and motionless god, and the study of this sub¬
ject we call a divine one. We perceive his action in
the highest heights of the world, but as an altogether
different one from the action of those substances which
can be perceived by the senses."

These are the words of Ptolemy on the first mover,
without any indication of the ninth sphere. But the
latter is mentioned by Johannes Grammaticus in his
refutation of Proclus, where he says: " Plato did not
know a ninth, starless sphere." And, according to Jo¬
hannes, it was this, i.e. the negation of the ninth sphere,
which Ptolemy meant to say.

Finally, there are other people who maintain that
behind the last limit of motion there is an infinite rest¬
ing body or an infinite vacuum, or something which they
declare to be neither a vacuum nor a plenum.    These
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