And again, it is the highest of all the others, because, as Aristotle says in the commencement of his book on the Soul, the Science is high, because of its nobility, and because of the nobleness of its subject and its certainty.

And this Science more than any other of those mentioned above is noble and high, for noble and high is its subject, which is the movement of the Heavens; and high and noble, because of its certainty, which is without any defect, even as that which springs from the most perfect and most regular principle.

And if any one believe that there is defect in it, it is not on the part of the Science, but, as Ptolemy says, it is through our negligence, and to that it must be imputed..