You should recognize that man’s soul, this single entity whose powers and parts we have described, may be compared to matter, and that the power of reasoning is its completed form. As long as the soul lies dormant and does not acquire its form from knowledge, then the nature of the soul is useless and exists in vain.
Maimonides, Rambam: Shemonah Perakim, The Eight Chapters; Maimonides' Introduction to Ethics of the Fathers; Perek Chelek; Discourse on the World to Come
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