The logical-comparative method is an essential tool in legal research, facilitating the analysis of norms and institutions by identifying similarities and differences between legal systems. This is crucial for a deep understanding of law and for proposing legislative reforms and harmonization. However, doubts persist regarding its logical foundation and its scope in the construction of legal knowledge. The objective of this study was to examine the logical foundation of this method and its usefulness in legal research. The aim was to understand its scope and improve its application in comparative law, elucidating whether it is based more on formal or rational logic. The research employed a qualitative approach, conducting a documentary and analytical study. Secondary sources such as legal literature and doctrines were reviewed, using content analysis to identify theoretical positions on the method. A theoretical comparison and an argumentative synthesis were then conducted to integrate the findings and establish its usefulness and limitations. A key finding revealed that the logical- comparative method in legal research is predominantly based on reasonable (practical/informal) logic, rather than formal logic. Reasonable logic allows arguments to be evaluated in real-life contexts, considering historical, cultural, and social factors. This is essential for a flexible and contextual interpretation and application of norms, allowing for a deeper understanding and effective adaptation of the law in diverse legal systems, as evidenced by the evolution of constitutional review in Panama.