After the concept of pure experience, Nishida spent three decades developing and refining his philosophical framework. His mature system is organized around a concept with no direct Western equivalent: basho (場所), literally "place" or "topos." The logic of basho, developed in a series of essays in the 1920s and 1930s, is Nishida's attempt to provide a philosophical ground that does not rely on the subject-object structure.
Nishida's logic of basho works by identifying nested levels of "place", fields within which things can appear and be determined. Ordinary logic operates in the "field of being" (yū no basho): things are determined by their positive properties, and logic is the logic of substances with attributes. Transcendental logic (Kant's contribution) operates in the "field of relative nothingness" (sōtaimu no basho): the field of consciousness, in which objects appear to subjects. But Nishida goes further: underlying both is the field of absolute nothingness (zettaimu no basho), the ultimate place that embraces both subject and object, both being and relative nothingness.
Absolute nothingness (zettaimu) is Nishida's most original and most difficult concept. It is not nihilism, it does not mean that nothing exists. Nishida is careful to distinguish absolute nothingness from mere emptiness or negation. Rather, absolute nothingness is the active, creative ground from which all beings, subjects, and objects emerge, a ground that functions precisely by having no fixed nature of its own, no substance, no essence that would constrain what can arise within it.
Absolute nothingness does not mean that there is absolutely nothing as if to suggest a nihilistic position. Rather, it means that the self has completely emptied itself, letting things present themselves just as they are.
— Global Critical Philosophy of Religion, 'Basho' (2025); based on Nishida Kitarō, From the Acting to the Seeing (1927)
The paradox is Nishida's calling card: absolute nothingness is "active and creative in forming the actual world" and "manifests or awakens to itself through self-awareness", yet it "functions through self-negation." It is a kind of ground that grounds by not being anything in particular, an absolute that is absolute precisely because it cannot be made into a determinate thing.
Nishida makes explicit contact between basho and the Zen concept of śūnyatā (emptiness), but he insists his logic is not merely theological or contemplative, it is a rigorous philosophical analysis of what must be the case for experience to be structured as it is. The self-awareness of absolute nothingness is not a mystical experience that transcends reason but the deepest structure of self-consciousness: when you are genuinely self-aware, what you encounter is not a substantial "I" but a self-emptying awareness that cannot fix itself as an object.
Nishida also, provocatively, connected his logic of basho to developments in quantum mechanics. He noted that quantum physics had undermined the classical subject-object dualism, the act of measurement disturbs what is measured; observer and observed cannot be cleanly separated. He saw quantum indeterminacy as empirical support for the claim that reality at its most fundamental level does not divide neatly into subjects and objects but is better described from the standpoint of the place that makes both possible.