The Pyramid texts show the same combination of the doctrines of the Osirian creed with those of the solar cult as the Book of the Dead.(152) But the combination is that of two mutually exclusive systems of theology which have been brought forcibly side by side without any attempt being made to fuse them into a harmonious whole. They display the usual tendency of the Egyptian mind to accept the new without discarding the old, and without troubling to consider how the new and old can be fitted together. It was enough to place them side by side; those who did not think the Osirian creed sufficient to ensure salvation, had the choice of the solar creed offered them with its prayers and incantations to the sun-god. But it was not an alternative choice; the heaven of the solar bark in its passage through the world of the night was attached to the heaven of Alu with its fields lighted by the sun of day. It is evident that the chapters which introduce the doctrines of the solar cult are a later addition to the original Book of the Dead. That was the text-book of the Osirian soul, with whose beliefs the doctrines of the solar cult were absolutely incompatible. While the one taught that the dead, without distinction, passed to the judgment-hall of Osiris, where, after being acquitted, as much on moral as on religious grounds, they were admitted to a paradise of light and happiness, the other maintained that only a chosen few, who were rich and learned enough to be provided with the necessary theological formulæ, were received in the solar bark as it glided along the twelve hours of the night, thus becoming companions of the sun-god in his passage through a realm of darkness that was peopled by demoniac forms. The Osirian and solar creeds issued from two wholly different religious systems, and the introduction of conceptions derived from the latter into the Book of the Dead, however subordinate may be the place which they occupy, indicates a revision of the original work. It was not until the book had gained a predominant position in Egyptian religious thought that it would have been needful to incorporate into it the ideas of a rival theology. But the incorporation had taken place long before the Pyramid texts were compiled, perhaps before the day when Menes united the two kingdoms of Egypt into one.