本文透過比較張載《橫渠易說》與《正蒙》二書，提出張載論本體有其一貫脈絡：以一氣之運作分言形上、形下，又對形上之氣多所偏重。在《橫渠易說》張載重視道、太極、神，至《正蒙》則重視太虛、太和、神等。此一貫脈絡同樣貫徹到張載的人性論與工夫論，張載提出天地之性與氣質之性、德性之知與見聞之知雖不可分割看待，但對天地之性與德性之知亦較為重視。為回復天地之性之至善，張載也提出大心、博學、重禮等工夫，重在掃除纏繞的習性，維持此心與萬物通而為一的天地境界。此一偏重形上本體的思想傾向，使張載雖與戴震同為以氣為本體的氣學家，卻呈現「回歸」與「發展」兩種相異的思想傾向。戴震反對言虛、神，反對天地之性與氣質之性的分別，主張博學以擴充心知，情欲之性發展得宜便是禮義，都與張載思想呈現不同的趨向。兩人之思想差距，正顯示兩種氣學的不同思想脈絡。

Comparing the two books, Heng Qu Yi Shuo and Correcting Youthful Ignorance, we could find out the consistent context in Chang Tsai's ontology. Chang Tsai had persistently thought the metaphysical and physical through the motion of material force, and he had one-sidedly emphasized the metaphysical. So he had emphasized the Way, the Great Ultimate and the Spirit in Heng Qu Yi Shuo, and the Great Vacuity, the Great Harmony and the Spirit in Correcting Youthful Ignorance. Chang Tsai had also proposed the nature of Heaven and Earth and the nature of material force should not be separately regarded, nor the innate knowledge of one's moral nature and the knowledge of what is heard or what is seen. Chang Tsai had believed some effects, such as enlarging the mind, extensive learning and valuing the rites, would eliminate the bad behavior. This consistent context means ”returning” and ”developing” are the two different ways of Chang Tsai's and Tai Chen's ontology in the philosophy of Material force.