Artificial intelligence (AI) as synthetic nature: Rethinking indeterminacy through the third landscape and terrain vague

This paper rethinks Artificial Intelligence (AI) in architecture as synthetic nature, not a deterministic tool of form-generation, but a cognitive, ecological, and philosophical agent capable of engaging uncertainty, latency, and spatial incompletion. It interrogates the conceptual foundations through which AI is currently integrated into architectural processes, proposing a new ontological reading. Against the dominant paradigm of AI as an instrument of optimisation and control, this research advances an alternative epistemology: one in which AI becomes a co-evolving presence within design, operating not through authorship but through attentiveness, negotiation, and emergence. Building on the ecological indeterminacy of Gilles Clément's Third Landscape, the potential latency of Ignasi de Solà-Morales' terrain vague, and the material vibrancy of Jane Bennett's vital materialism, the paper constructs a conceptual framework where architectural value is no longer tied to resolution, function, or intentionality, but to relational intelligence, material responsiveness, and temporal openness. Within this post-anthropocentric paradigm, AI is understood as a participant in distributed agency, an interpreter of urban margins, a listener to material behaviour, a sensor of the indeterminate. Through the interpretive analysis of four experimental projects, Hylozoic Ground, H.O.R.T.U.S. XL Astaxanthin.g, Living Architecture, and ZHAI/ZHCODE the research illustrates how AI engages with environmental stimuli, material instability, and spatial ambiguity without reducing them to closure, but rather sustains processes of co-formation, metabolic responsiveness, and emergent adaptation. Ultimately, the paper advocates for an architectural ethic grounded in co-existence rather than control, in transformation rather than resolution. In the entanglement between human, machine, and matter, AI emerges not as a servant of design but as an interlocutor in the poetics of the unfinished.