Short answer. The obligation is annulled. Under Article 1183 of the Civil Code, impossible conditions void the obligation that depends on them. The same result follows if the condition violates good customs, public policy, or the law. Neither party can be held to a contract whose entire performance rests on something that cannot happen.
What the law says
Impossible conditions, those contrary to good customs or public policy and those prohibited by law shall annul the obligation which depends upon them.
Civil Code, Article 1183 — Impossible and Unlawful Conditions. Read the full provision →
What the rule in Article 1183 provides
Article 1183 covers three types of conditions that destroy the obligation: physically impossible ones, those contrary to good customs or public policy, and those prohibited by law. In all three cases, the result is the same — the obligation that depends on the condition is annulled. This is different from the rule in wills, where an impossible condition in a legacy is merely disregarded while the gift survives. In ordinary contracts, an impossible suspensive condition does not suspend the obligation until some uncertain event — it voids the obligation altogether, because there is nothing that can ever bring it into existence.
What happens if the contract is divisible
Not every part of a contract necessarily collapses. Article 1183 contains an important qualification: if the obligation is divisible, that part thereof which is not affected by the impossible or unlawful condition shall be valid. So if the contract has multiple, separable parts — one conditioned on an impossibility, others that are unconditional or conditioned on something achievable — only the tainted part is annulled. The rest of the contract may still be enforceable. Whether a particular contract is divisible in this sense depends on its terms and whether the parties would have entered the remaining portions without the void section.
The special rule for a 'not-to-do' condition
Article 1183 includes a distinct rule for negative impossible conditions: the condition not to do an impossible thing shall be considered as not having been agreed upon. This is the reverse of the ordinary rule. If the condition is 'you must do X and X is impossible,' the obligation is annulled. But if the condition is 'you must not do X and X is impossible anyway,' the condition is simply ignored and the obligation stands unconditionally. The logic is that a promise not to do something no one could do anyway is meaningless — so the law removes the meaningless condition and enforces the underlying obligation.
Why this matters for a contract dispute
If you are trying to enforce a contract where the other side insists the triggering condition was impossible from the start, Article 1183 may be the center of your dispute. Whether the condition was truly impossible, whether the contract is divisible, and whether a negative form of the condition applies can all change the outcome significantly. These are factual and legal questions that depend on the specific contract language and the circumstances at the time it was signed. Legal advice on your specific documents is important before drawing any conclusions about what remains binding.
Cases citing this provision
These Supreme Court decisions cite the provision above. We list them so you can read them yourself; the summaries of what each decided are not ours to give.
- Heirs of Severina San Miguel, et al. vs. The Hon. Court of Appeals, G.R. No. 136054, September 5, 2001 — read the decision on LawPhil →