"Yūshinron" (有心論, "Heart Theism") is a song by Japanese rock band Radwimps, released on July 26, 2006, as the second of three singles from the band's fourth album, Radwimps 4: Okazu no Gohan.

The song was popular enough to be certified gold by the Recording Industry Association of Japan as a full-length cellphone download nine months after its release, one of four songs from Radwimps 4 to achieve this. The music video of the song was also awarded at the Space Shower Music Video Awards 2007, with the award for Best Art Direction.

The song begins as vocals solely backed by acoustic guitar, with the rest of the band's instruments added before the first verse, with the instruments played much more frantically in choruses.

The lyrics of the song are introspective, and involve vocalist and songwriter Yojiro Noda acknowledging the "parts of [himself] that [he] hates and likes" in regards to a romantic relationship. He reasons that he decided to hate his lover as a protective measure, as he realised he would be hated at the end of the relationship no matter of how it turned out. He also reasons that one day he will want someone to love him, and that he will also make the first move then. He describes his lover as "the only earthly goddess" as well as a ningen sentaku-ki (人間洗濯機, "washing machine for humanity"). He asks if she made the earth round, so that nobody could cry in the corner of it, and says that when she is not there, he looks for a corner to cry.

The song also mentions two types of people, ningen fushinsha (人間不信者, "humanity unbelievers") and ningen shinsha (人間信者, "humanity believers"). The unbelievers "curse the future," while the believers "dream of the future" and are the suicide candidates of tomorrow. Noda describes his lover as "giving eternal happiness to people who were, two second ago, suicide candidates." He believes his lover is in his heart, sending him love through his White and red blood cells.

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