What is casual condition?

The second part of Article 1182 of the Civil Code of the Philippines discusses the concept of casual condition, to wit:

ART. 1182. When the fulfillment of the condition depends upon the sole will of the debtor, the conditional obligation shall be void. If it depends upon chance or upon the will of a third person, the obligation shall take effect in conformity with the provisions of this Code. (1115) (Emphasis supplied)

Casual condition may be viewed in two aspects: depends upon chance or depends upon the will of a third person. Example, X obliges himself in favor of Y to give Php10,000 to Y if he wins a case in the Supreme Court. In this example the condition is subject to the will of a third person. Hence, it is a casual condition.