Two Japanese scientists who received Nobel Prizes in 2025 shared insights into their long and challenging paths to recognition during a recent forum at the University of Tokyo. Shimon Sakaguchi, awarded the Nobel Prize in Physiology or Medicine, and Susumu Kitagawa, recipient of the Nobel Prize in Chemistry, discussed the perseverance and critical thinking that underpinned their groundbreaking research, which initially faced skepticism and professional rejection.

Sakaguchi, an honorary professor at the University of Osaka, was honored for his discovery of regulatory T cells—immune cells that suppress excessive immune responses. When he first published his findings in 1982, the scientific community largely dismissed the existence of such cells. He encountered sharp criticism, including from Nobel laureates in immunology, and it took two decades before his work gained broad acceptance. Reflecting on this period, Sakaguchi emphasized the importance of consistency and rigorous verification in his experiments, explaining that his confidence came from repeatedly confirming his results through meticulous techniques he had mastered over years of study.

Kitagawa, a distinguished professor at Kyoto University, received the Nobel Prize for developing metal-organic frameworks, porous materials capable of storing gases, which he synthesized by combining metal ions and organic molecules. In 1997, after presenting his findings at a conference in the United States, Kitagawa faced harsh scrutiny, with critics challenging the accuracy of his data and methodology. Despite the initial reception, Kitagawa said the strength of his experimental data and the trusted collaboration with a co-researcher sustained his resolve to continue. He described the experience as emotionally taxing but ultimately a formative challenge that he learned to embrace.

Both laureates highlighted how their work confronted prevailing scientific assumptions, underscoring the necessity of relying on solid empirical evidence in the face of doubt. They also spoke about their broader philosophies toward scientific inquiry. Sakaguchi noted that research is deeply personal and finite in a human lifespan, stressing the fulfillment that comes from pursuing original ideas and generating new knowledge through direct engagement. Kitagawa encouraged questioning accepted truths and advised young researchers to embody what he terms the “Three Cs”: Courage, Challenge, and Curiosity. He urged his students to take on investigations that spark genuine interest, regardless of potential obstacles.

The forum also touched on the role of knowledge acquisition in the modern era. Both scientists cautioned against overreliance on rapidly accessible information, such as that provided by artificial intelligence, emphasizing the need to internalize and critically assess knowledge independently. Kitagawa encouraged thorough reading and reflection, while Sakaguchi said true understanding requires time and effort to reach a level of personal satisfaction and original thought. They agreed that scientific progress demands more than accepting ready-made answers—it calls for verification through hands-on research and thoughtful analysis.