Substance / Essence: The terms substance and ESSENCE which – rightly or wrongly – are taken in practice to be more or less synonymous, differ in that substance refers to the underlying, immanent, permanent nature of a basic reality, whereas ESSENCE refers to the reality as such, that is as “being” and, in a secondary sense, as the absolutely fundamental nature of a thing. The notion of ESSENCE denotes an excellence which is, so to say, discontinuous in respect to accidents, whereas the notion of substance implies on the contrary a kind of continuity, and this is why we employ it when speaking of Atma in connection with Maya. (GTUFS: FormSR, Atma-Maya)
Substance may be compared to the center of a spiral, and Essence to the center of a system of concentric circles; one may also say that the notion of Substance is nearer to that of the Infinite and the notion of Essence nearer to that of the Absolute; again, there is in Substance an aspect of femininity and in Essence an aspect of masculinity. (GTUFS: LogicT, The Argument Founded on Substance)
However, the terms “substance” and “ESSENCE” are synonymous inasmuch as they simply designate the archetypal content of a phenomenon. (GTUFS: PlayMasks, The Liberating Passage)
In fact, the terms “substance” and “ESSENCE” are often synonymous, but strictly speaking, the first term suggests a continuity, and the second, a discontinuity; the first refers more to immanence, and the second, to transcendence. On the one hand, one distinguishes between the substance, which is permanent, and the “accidents,” which change; on the other hand, one makes a distinction between the ESSENCE, which is the fundamental nature – whether it is a question of the Principle or of manifestation – and the “form,” which is its reflection or mode of expression. (GTUFS: SurveyME, Creation as a Divine Quality)