孟子明示其志曰：「我亦欲正人心，息邪說，距詖行，放淫辭，以承三聖者。」而其思想博大精深而切合時蔽，尤以民重君輕與心學之思想，更是開前人之所未發。其思想立基於「天道觀」，而立論以「性善說」為本，由此而開啟個人修養之「內聖」與兼善天下之「外王」之君子道程。本文之主題，則集中於孟子之心學特質部份作探討。人異禽獸之「幾希」，即是所謂的「仁義之心」。而此心更非由外鑠我，乃我本固有之，而此心乃人人本有、個個具足，若能以此為本擴而充之，進則足以保四海、退則足以事父母，更能「盡心知命進而以事天」，此「幾 希」不可謂不重要矣！而此固有之「心」中之底蘊更值得仔細探究探討，其所具之特質到底為何，得以為立身知命之本。本文彙整時主要是以「顯而易見」與「有其必然性」來做為選輯的原則，擇要整理出「心」之所具的特質十二種。

Mencius clarifies his will: "I would like to lead people's heart to the correct way, oppress wicked theories, resist one-sided conduct, and banish seductive expressions, so as to follow the teaching of three sages. "Mencius's theory, appropriate to the contemporary time, is far-reaching and thought-provoking in which his theory of the heart and his focus on the people rather than on emperors are unprecedented. His theory is based on the perspective of the natural law, while his narration is from the aspect of men who are naturally good. Following these two endeavors can a person implement his way to enlighten personal inward sacredness as well as outward kingship which can spread goodness to the world. The subject of this thesis focuses on characteristics of Mencius's theory of heart. The difference between human beings and beast lies in the so-called heart of kindness and justice. The heart of kindness and justice does not impose from outer world but the inward heart which exists in everyone's mind. Dispersing from the basis of the heart can proceed to secure the world or recede to be filial to parents. Further, following the heart can realize the truth of self and traverse on the way of the great spirit. The heart is significant. It is worthwhile to carefully explore the essence of the heart. What characteristics does the heart bear to become the basis of realizing self? The thesis induces twelve characteristics of the "heart, "all of which are based on principles of conspicuousness and necessity.