an by the Arabic
numerals foreshadowed the result of a far more important--a
political--contest between those rival names. But, before showing how
the Arabian intellect pressed upon Rome, and the convulsive struggles of
desperation which Rome made to resist it, I must for a moment consider
the former under another point of view, and speak of Saracen philosophy.
[Sidenote: The writings of Algazzali.] And here Algazzali shall be my
guide. He was born A.D. 1058.

Let us hear him speak for himself. He is relating his attempt to detach
himself from the opinions which he had imbibed in his childhood: "I said
to myself, 'My aim is simply to know the truth of things; consequently,
it is indispensable for me to ascertain what is knowledge.' Now it was
evident to me that certain knowledge must be that which explains the
object to be known in such a manner that no doubt can remain, so that in
future all error and conjecture respecting it must be impossible.
[Sidenote: The certitude of knowledge.] Not only would the understanding
then need no efforts to be convinced of certitude, but security against
error is in such close connexion with knowledge, that, even were an
apparent proof of falsehood to be brought forward, it would cause no
doubt, because no suspicion of error would be possible. Thus, when I
have acknowledged ten to be more than three, if any one were to say, 'On
the contrary, three is more than ten, and to prove the truth of my
assertion, I will change this rod into a serpent,' and if he were to
change it, my conviction of his error would remain unshaken. His
manoeuvre would only produce in me admiration for his ability. I should
not doubt my own knowledge.

"Then was I convinced that knowledge which I did not possess in this
manner, and respecting which I had not this certainty, could inspire me
with neither confidence nor assurance; and no knowledge without
assurance deserves the name of knowledge.

"Having examined the state of my own knowledge, I found it divested of
all that could be said to have these qualities, unless perceptions of
the senses and irrefragable principles were to be considered such.
[Sidenote: Fallibility of the senses.] I then said to myself, 'Now,
having fallen into this despair, the only hope of acquiring
incontestable convictions is by the perceptions of the senses and by
necessary truths.' Their evidence seemed to me to be indubitable. I
began, however, to examine the objects of sensation