As highlighted by Kepler’s laws discovered in the 17th century, mathematical modeling, which describes measured data using simple mathematical expressions, has established a foothold in understanding various physical phenomena. However, in modern science, which makes full use of advanced measurement techniques and deals with complex phenomena, data that are difficult to understand are becoming more and more apparent. Our laboratory endeavors to establish guiding principles for a data-based and unambiguous understanding of all physical phenomena. In an interactive cycle between theoretical and empirical research, we explore the mathematics of Bayesian statistics and promote understanding of complex phenomena through interdisciplinary collaboration with researchers in natural science and industry.