Brahma Knowledge, by L. D. Barnett, [1911], at sacred-texts.com
§ 17. Relation of Universal to Individual Soul.—It is a first principle of the Upanishads that the numberless individual souls are really one with the Universal Self. But how is this relation conceivable? To this question no answer is vouchsafed. The older texts instead give us
cosmogonic myths, which realistically depict a Universal Spirit creating the phenomenal world and then animating it as world-soul; and the latter they simply identify with the self of the individual, sometimes more pantheistically (Ch. VI. iii.), sometimes more idealistically (B.A.II. iv. 5, III. iv. 1, v. 1, etc.). But why should there be this division between the one Absolute Soul and the innumerable individual souls condemned to suffer the intellectual darkness and physical sorrows of embodied life? The Upanishads find a solution in their theory of karma, the acts done in previous births requiring further embodiment to work away their influence upon the soul. This implies a regressus ad infinitum, as every act is the resultant of a former act; and this conclusion is cheerfully drawn by the later Vedānta, which thus avoids the necessity of explaining the "origin of evil." The older Upanishads, whose cosmogonies contradict this theory, simply avoid the question.
The theory which begins to appear in a somewhat late Upanishad (the Maitrāyaṇīya), that the Soul conceives division and plurality in consequence of the delusive attractions of physical Nature, and hence assumes embodied form and comes under the influence of "works," is partly connected with the dualism of the Sānkhya school, and partly with the theory of "illusion" developed in the later Vedānta (see § 16). Śankara generally regards the universe itself, i.e. the
aggregate of subjects and objects of experience, as created in order to furnish finite souls with experiences in recompense of previous "works"; but the reason moving the Supreme Brahma to render himself an efficient and material cause of a universe distinct from himself, says Śankara, can only be motiveless sport (see commentary on Brahma-sūtra, II. i. 33).