陸九淵稱宇宙的本體為「理」，人的本體是宇宙本體流行所形成之分殊的本體，陸九淵用「本心」指稱人的本體。這個分殊的本體同於宇宙的本體，所以說「心即理」。這是本體義的「理一分殊」思想。 宇宙本體流行所形成的規律落在人間世就形成人倫道德，道德是源自宇宙的本體，而人的本體同於宇宙的本體，由此而說，人倫道德便源自人的本體。宇宙流行的規律呈現的是必然的現象，而人倫道德則是「應然」的行為，陸九淵將人倫道德源自人的本體，因此，應然性=必然性。陸九淵這樣的說法，可以說是保障了人倫道德的必然性以及內在性。 陸九淵藉由孔子對顏回所說的「三轉語」：「克己復禮為仁。一日克己復禮，天下歸仁焉。為仁由己，而由人乎哉？」說明道德實踐必須先發明自己的本心，再到宇宙的本體，再回到自己的本心，也就是從分殊到理一，再由理一到分殊，一個上下往返的過程。綜上所論，陸九淵的整個思想理論，是以「本心」為核心，運用「理一分殊」的思想及方法論所建構起來的。

LU Jiu-Yuan called essence of the universe as 「Base」. The universe's essence operated and diversified into different shapes and formed human's essence, which was called 「Heart-in-Itself」 by LU Jiu-Yuan. The diversified essence and the universe's essence are the same; therefore, it can be said that 「Hear is Base」. This was the 「One base, different shapes」 in ontology. The operation pattern of the universe presented a 「inevitable」 phenomenon, but the morality of human relations was a 「ought to be」 behavior. LU Jiu-Yuan thought the morality of human relations came from the operation of the university; therefore, 「inevitable」=「ought to be」, assuring the necessity and the intrinsic factors of the morality of human relations. By the 「Three Cryptic Sayings」 that Confucius taught YAN hui, LU Jiu-Yuan illustrated that to realize morality, one must discover his own heart, follow the universe's essence and return to one's own heart, representing a circulated journey that starting from 「different shapes」 to 「one base」 and return to 「different shapes」 again. In summary, LU Jiou-Yuan's overall thinking theory was centered with 「heart-in-itself」 and constructed with the thinking and methodology of 「one base, different shapes」.