Systematic review of fuzzy logic: Methods, applications, and research challenges

Fuzzy logic is a significant approach for addressing uncertainty, partial truth, and approximate reasoning in complex decision-making contexts. This review systematically examines the methodological foundations and major applications of fuzzy logic in decision support, healthcare, smart agriculture, control engineering, recommender systems, and explainable artificial intelligence. Guided by a PRISMA-based framework, the study analyzes fuzzy logic model categories, application domains, key strengths, and persistent challenges. The findings show that fuzzy logic remains highly relevant because it combines computational flexibility with human-interpretable reasoning. Nevertheless, the review also reveals that many existing studies require stronger empirical validation, greater transparency in model design, and more systematic comparisons with alternative approaches. Future research should therefore prioritize the development of reproducible, integrated, and practically deployable fuzzy systems.