This philosophical theory of the Primal Cause was adapted by Jewish scholars to the Biblical theory of the Creator. The universe is a living, organized being, of which the earth is the centre. Any changes on this earth are due to the revolutions of the spheres; the lowest or innermost sphere, viz., the one nearest to the centre, is the sphere of the moon; the outermost or uppermost is “the all-encompassing sphere.” Numerous spheres are interposed; but Maimonides divides all the spheres into four groups, corresponding to the moon, the sun, the planets, and the fixed stars. This division is claimed by the author as his own discovery; he believes that it stands in relation to the four causes of their motions, the four elements of the sublunary world, and the four classes of beings, viz., the mineral, the vegetable, the animal, and the rational. The spheres have souls, and are endowed with intellect; their souls enable them to move freely, and the impulse to the motion is given by the intellect in conceiving the idea of the Absolute Intellect. Each sphere has an intellect peculiar to itself; the intellect attached to the sphere of the moon is called “the active intellect” (Sekel ha-poʻēl). In support of this theory numerous passages are cited both from Holy Writ and from post-Biblical Jewish literature. The angels (elohim, malakim) mentioned in the Bible are assumed to be identical with the intellects of the spheres; they are free agents, and their volition invariably tends to that which is good and noble; they emanate from the Primal Cause, and form a descending series of beings, ending with the active intellect. The transmission of power from one element to the other is called “emanation” (shefaʻ). This transmission is performed without the utterance of a sound; if any voice is supposed to be heard, it is only an illusion, originating in the human imagination, which is the source of all evils (ch. xii.).