It is much more important to mark the distinction between a stipulation which only has the effect of confining a promise to certain cases, and a condition properly so called. Every condition, it is true, has this effect upon the promise to which it is attached, so that, whatever the rule of pleading may be, /2/ a promise is as truly kept and performed by doing nothing where the condition of the stipulated act has been broken, as it would have been by doing the act if the condition had been fulfilled. But if this were all, every clause in a contract which showed what the promisor did not promise would be a condition, and the word would be worse than useless. The characteristic feature is quite different. A condition properly so called is an event, the happening of which authorizes the person in whose favor the condition is reserved to treat the contract as if it had not been made,--to avoid it, as is commonly said,--that is, to insist on both parties being restored to the position in [319] which they stood before the contract was made. When a condition operates as such, it lets in an outside force to destroy the existing state of things. For although its existence is due to consent of parties, its operation depends on the choice of one of them. When a condition is broken, the person entitled to insist on it may do so if he chooses; but he may, if he prefers, elect to keep the contract on foot. He gets his right to avoid it from the agreement, but the avoidance comes from him. Hence it is important to distinguish those stipulations which have this extreme effect from those which only interpret the extent of a promise, or define the events to which it applies. And as it has just been shown that a condition need not be insisted on as such, we must further distinguish between its operation by way of avoidance, which is peculiar to it, and its incidental working by way of interpretation and definition, in common with other clauses not conditions.