多瑪斯在亞理斯多德哲學基礎上建構了系統的「習性」理論，與《孟子》的「氣」概念有許多相通之處：兩者在道德實踐中的作用相似，以相似的方式生成、增進、減退和毀滅，都既受意志指揮又有其相對穩定性。《孟子》氣論的詮釋難點，如身體之氣與精神之氣的關係、志與氣的關係、養氣與性善論的衝突等，可以藉由習性論來解決。氣論與習性論具有不同的形上學基礎，分別從靜態和動態方面把握了習性與氣的本質。習性論能闡明許多孟子「難言」處，彰顯孟子使用「次」「餒」「養」等隱喻的妙處；而孟子的「浩然之氣」論述則可突出習性的「剛」性，補充習性論在此方面的不足。

Based on Aristotelian philosophy, St. Thomas Aquinas developed a systematic theory of habit(habitus), which shares many common features with qi (氣) in the Mengzi: they play similar roles in moral practice, are produced, increased, decreased and corrupted in the same way, and they are both commanded by the will, while maintain a relative stability. Difficult problems in interpreting the Mencian theory of qi can be solved with the theory of habit, such as the relation between corporal and spiritual qi, between zhi (志) and qi, and the conflict between his belief in good human nature and the effort required by developing qi. The two theories are built upon different metaphysical basis, and when put together, would be able to fully grasp the nature of qi and habit by focusing respectively on dynamity and stability. With the theory of habit, it is able to articulate issues that Mencius claimed to be “hard to say”, and to bring out the nuances of Mencius’ use of metaphors such as stationing (次), hunger (餒) and nourishing (養). Mencius, with his explication of vast, flowing qi (浩然之氣), reveals the robustness (剛) of habit, which is absent in St. Thomas’ theory.