以品德高尚之人作為楷模來形塑個人行為，這是當代德性倫理學的一個重要主題。鑑於阿奎那將自然視為理性引導的人的善行的楷模，該主題涉及自然和形上學領域。在阿奎那的論述中，理性的行動者自然傾向透過模仿自然來尋求善。要具備道德德性和實踐智慧，需模仿一位品德高尚的他人，其「第二天性」構成了道德成長的習性。這種美德的習性符合並根植於「實踐智慧」的楷模中，在各種自然事物的自然作用中根據其獨特的行為模式找到共同的可理解痕跡。作為人類行為者的道德「第二天性」在他的道德傾向和行為中顯示出來，成為他人模仿的近身楷模，符合自然事物作用中實踐智慧的自然顯現。

Modeling one’s actions on an exemplar of a virtuous person is a theme in contemporary virtue ethics. For Aquinas, it has a natural and metaphysical breadth based on his account of nature as an exemplar for virtuous human actions directed by reason. In Aquinas’s account, rational agents are naturally disposed to seek what is good by the imitation of nature. Becoming morally virtuous and practically wise requires imitation of a virtuous other whose “second nature” constitutes the habit of moral flourishing. Such habit of virtues conforms to and is rooted in the patterns of “practical wisdom” found in common intelligible traces of natural agency of a variety of things of nature according to their distinct modes of action. The virtuous “second nature” of a human agent manifest in moral dispositions and conduct is a proximate exemplar for the imitation by others, conformed to the natural manifestations of practical wisdom in the agency of natural things.