This paper focuses on Hector-Neri Castañeda's significant contributions to metaphilosophy. In his 1980work, On Philosophical Method, Castañeda articulates a unique perspective, characterizing philosophy as fundamentally a dia-philosophical activity. By asserting the supremacy of synthesis over analysis within the metaphilosophical hierarchy, his account provides a purely theoretical defense of philosophical plural-ism devoid of any relativistic inclinations. Despite Castañeda's enduring influence and profound impact on ongoing discussions in ontology, logic, and the philosophy of language, his metaphilosophical insights have largely been neglected. In the context of today's increasingly diverse philosophical landscape, this paper posits that Castañeda's pluralist metaphilosophy retains substantial theoretical relevance.