His theological view of science marks an epoch.

As to the "waters above the firmament," Isidore contends that they must be lower than, the uppermost heaven, though higher than the lower heaven, because in the one hundred and forty-eighth Psalm they are mentioned AFTER the heavenly bodies and the "heaven of heavens," but BEFORE the terrestrial elements.

As to their purpose, he hesitates between those who held that they were stored up there by the prescience of God for the destruction of the world at the Flood, as the words of Scripture that "the windows of heaven were opened" seemed to indicate, and those who held that they were kept there to moderate the heat of the heavenly bodies.

As to the firmament, he is in doubt whether it envelops the earth "like an eggshell," or is merely spread over it "like a curtain"; for he holds that the passage in the one hundred and fourth Psalm may be used to support either view.
Having laid these scriptural foundations, Isidore shows considerable power of thought; indeed, at times, when he discusses the rainbow, rain, hail, snow, and frost, his theories are rational, and give evidence that, if he could have broken away from his adhesion to the letter of Scripture, he might have given a strong impulse to the evolution of a true science.( 203) (203) For Cosmas, see his Topographia Christiana (in Montfaucon, Collectio nova patrum, vol.ii), and the more complete account of his theory given in the chapter on Geography in this work.

For Isidore, see the Etymologiae, lib.