R2d § 226
How an Event May Be Made a Condition
An event may be made a condition either by the agreement of the parties or by a term supplied by the court.
Professor's notes
Element: an event may be made a condition either by the agreement of the parties (express condition) or by a term supplied by the court to deal with the omissions of the parties (constructive condition).
This sets up the two kinds of condition: express and constructive.
Common misunderstanding: students think every condition must be in the writing. Constructive conditions (especially of exchange: Kingston v. Preston, § 234) are court-supplied to make a workable contract out of bare promises. Express conditions are interpreted strictly (§ 237 substantial performance does NOT cure express conditions); constructive conditions are interpreted flexibly. The classification drives the doctrine.
Text
R2d § 226. How an Event May Be Made a Condition.
An event may be made a condition either by the agreement of the parties or by a term supplied by the court.