The first of the terms identified in the Tanya is hishtalshelut, "evolution." The concept of hishtalshelut, as used in Chassidic thought, refers to the metaphysical process whereby the complex and finite reality of the universe unfolds out of God's absolute oneness. The underlying dynamic of hishtalshelut is that of ila v'alul, temporal "cause and effect." According to Kabbalah, the universe evolves, like the trunk of a tree, as rings within rings with G-d at its center. The root of the Hebrew word taba'at ("ring") is teva, which itself means "nature." Nature and the evolutionary process are one and the same. Both suggest an underlying unity which serves as the source of energy for a vast creative enterprise.
As indicated above, the Kabbalah of the Ramak focuses primarily on the process of hishtalshelut, describing in detail the array of Divinely emanated forces which serve to mediate between the infinite Creator and His finite Creation. These forces, or sefirot, emerge in a particular sequence, ultimately remaining as the underlying formula for all creative process within the universe. Although the Ramak was a mystic in every sense of the word, whose inspiration derived mainly from the opaque imagery of the Zohar, his conceptual focus on hishtalshelut resulted in a quasi-philosophical exposition of the themes which lie at the heart of Kabbalah. The dialect of philosophical discourse was deemed by him to be most effective in describing a process which itself reflected a sequential logic and coherence.