Abstract: The concept of Causa in Civil Law system originated in ancient Roman law. In the 14th century, the Commentators found the general theory of Causa when interpreting the texts of Roman law through Aristotelian and Thomistic philosophical conceptions. In 16th century, late scholastics achieved the synthesis between Roman law and Aristotelian and Thomistic moral philosophy. They concluded that the promises are enforceable if they are made for the virtues of liberty and commutative justice. The insufficiency of modern contract theory implies the philosophical advantage of the doctrine of Causa. Legal science can not be isolated from philosophy. Laws should be rooted in moral, improve human virtue, and reflect the multiple pursuits in promises.

Key words: binding force of contracts, doctrine of Causa, philosophical origin