“Thus the sefiroth are here conceived as worlds but also as seals, as minting stamps of all reality—just as the Platonists speak of the ideas as seals—but they are also the ”luminous mirrors” of the deity through which its light is reflected in all reality.
Some texts specify, much as does the “Book of the Five Substances,” a distinct “world of life,” which is distinguished from the world of the intellect and from that of the soul in the hierarchy of being.
‘En-sof as a name of the hidden God in his transcendence is still unknown in these texts, suggesting that they preceded the writings of the Gerona circle. But they also readily make use of adverbial phrases of the kind we have already discussed with regard to the Infinite and often speak of the “light whose sublimity has no end.”
The fact that the name Araritha was used for the primordial and transcendent being, as we have mentioned, proves that the writers felt the need to find some name for the absolute unity, which is above all these “worlds,” the “One where everything originates, where everything has its existence and to which everything returns.”
The absence of the name ‘en-sof can therefore be no accident.”
Gershom Scholem, Origins of the Kabbalah, p. 330.