The Supreme Divine is “One without a second”. Yet we can still make mental distinctions between the Transcendent, the Universal and the Individual aspects of the Divine, as that is the nature of the mental consciousness, and we can focus on one or another of these aspects without forgetting the unity and oneness that contains, constitutes and supports each aspect. To do this, we recognise that we cannot limit the Divine by any specific aspect or identification. “Not this, not that” is intended to remind us that these definitions cannot limit the Divine.
Similarly, the active nature in the individual, in the world, and in the cosmos, Prakriti, can be looked at as separate aspects of the Divine Shakti, but without limiting the Shakti through these identifications. There is the supreme nature Para Prakriti, which exceeds any limits or definitions we create to identify the action of nature in the universal creation.
Sri Aurobindo writes: “It is a mistake to identify the Mother with the lower Prakriti and its mechanism of forces. Prakriti here is a mechanism only which has been put forth for the working of the evolutionary Ignorance. As the ignorant mental, vital or physical being is not itself the Divine, although it comes from the Divine — so the mechanism of Prakriti is not the Divine Mother. No doubt something of her is there in and behind this mechanism maintaining it for the evolutionary purpose; but what she is in herself is not a Shakti of Avidya, but the Divine Consciousness, Power, Light, Para Prakriti to whom we turn for release and the divine fulfillment.”
Sri Aurobindo, Integral Yoga: Sri Aurobindo’s Teaching and Method of Practice, Chapter 4 The Divine, The Gods and the Divine Force, The Divine Mother pp. 88-90