Cause distinguished from motive
Article 1351 of the Civil Code provides:
ART. 1351. The particular motives of the parties in entering into a contract are different from the cause thereof. (n)Motive is the purely personal or private reason which a party has in entering into a contract. It is different from the cause of the contract. Article 1351 embodies “a principle which is common to both Philippine law and American jurisprudence.”[1][2]
The cause of the contract is the proximate reason of the parties to enter into a contract while motive is the remote reason of the parties in entering into a contract. The former is always the same for the contracting parties while the latter differs for each contracting party. Moreover, the illegality of the cause affects the existence or validity of the contract while the illegality of the motive does not affect the existence or validity of the contract.
[1] Report of the Code Commission, p. 137.
[2] De Leon. (2014). Obligations and Contracts.