Concept of possible, impossible conditions

Impossible and possible condition refers to whether or not a condition can be fulfilled either physically or legally.

The concept of impossible condition is discussed on Article 1183 of the Civil Code of the Philippines, viz:

ART. 1183. Impossible conditions, those contrary to good customs or public policy and those prohibited by law shall annul the obligation which depends upon them. If the obligation is divisible, that part thereof which is not affected by the impossible or unlawful condition shall be valid. 

The condition not to do an impossible thing shall be considered as not having been agreed upon. (1116)

Article 1183 only applies to cases where the impossibility already existed at the time the obligation was constituted. If the impossibility arises after the creation of the obligation, Article 1266 of the Civil Code applies.[1]

Moreover, impossible conditions can either be physically or legally. It is physically impossible if it is incompatible with or contrary with nature. On the other hand, it is legally impossible if they are contrary to good customs, public policy or those that are prohibited by law.[2]

Furthermore, the general rule is that if the condition is impossible, it is void. If the condition is divisible, only the part affected by the impossible condition will be void. 

[1] De Leon. (2014). Obligations and Contracts. 

[2] Rabuya. (2019). Obligations and Contracts.