陳乾初對於人性的看法，是由對於孔孟學說的理解來肯定性善，認為主張性善才能使自暴自棄者無所諉其過。他以惻隱、羞惡、辭讓、是非皆就氣、情、才而言，它們是性善的具體呈現處，因此是有善無惡的。他反對宋儒以「人生而靜以上」言本體，這樣便是離人求體，落於虛玄。性善本體雖是當下本有，後天不能有所增損，然此本體是要經由實踐方可契入，並非空口談論即可知性。故乾初強調要有擴充盡才的工夫修養，使吾人之性善能夠具體的呈顯、實踐出來，而性善本體亦在工夫實踐下被證成。性善背後的超越根據是天道，性源於天道，故是粹然至善，而天道的具體內容則需要透過人的道德實踐才能展現出來。其理欲觀亦有相同的態度，以人欲為天理的載體，人欲的恰好處即是天理的呈現。乾初反對宋儒將性劃分為「氣質之性」與「本然之性」，認為性善是要在氣上見。就氣質為義理之載體而為其具體呈現處而言「氣質即義理」，並非是將義理的超越義抹滅而歸之於形下。 對於惡的問題，乾初一反前儒以氣質、人欲為惡，而是以「習」來解釋人之有惡。人之有過惡，是歸諸於可以決定習於善或習於惡的人的意志，善與惡的界線只在於人的自我抉擇、自由決意。乾初對於「惡」的理論，由前儒以氣質、感性等對人實踐道德的影響，轉而著眼於人在自由決意下所做的選擇，亦即是由在外的影響轉而注意人內心的立意處。工夫論部分，有體證本心的先天工夫與於事上作的後天工夫。他認為無論是為學、立志，亦或是知過改過等後天的工夫修養，都要以本心為根據，只有反求本心，並且以其為生命的主宰，這便是一日千里之學。但此逆覺體證的工夫是要在人倫日用中體悟，而不是透過靜坐等冥思玄想的方式來把握本心。 As a student of Liu Tsung-chou, Chen Chien-chu (1604-1677) particularly sticks to his master’s doctrine of ch’i. Chen tries to apply this doctrine in concretizing Mencius’ thesis of the instrinsic good of human nature. In distinguishing from Liu, Chen is not interested in expounding the essence of Nature (hsing) as such. Rather, he focuses on the realization of the goodness of human nature. Negatively speaking, he opposes the position which separates ch’i from human nature. For him, apart from ch’i, human nature would become empty. Positively speaking, ch’i represents the source of the dynamic in realizing the goodness of human nature. This hence lends support to Liu’s interpretation of Nature (hsing) as ch’i, which rejects any reduction of ch’i to material force. Correlatively, in his theory of praxis, Chen refutes to see the origin of evil in ch’i or desire. For him, the rise of evil depends entirely upon the will’s way in acquiring good. It is in terms of individual choice that the distinction between good and evil can be established. This also signifies the application of his doctrine of ch’i to moral praxis. All this indicates that for Chen, learning, determination or cultivation must be grounded in the returning to the orignal mind. Methodologically, it is basically a procedure of radical awareness, which is different from any still meditation or speculation.
