Precision of terms
Suppose that a potential employer and employee have indicated their willingness to enter into a contract of employment with each other. To be enforceable, the contract terms must be reasonably ascertainable and not too vague. If there is a major doubt as to the meaning of an important provision, and the doubt cannot be resolved, then the agreement may be declared void for uncertainty. So if any wage provision in a purported contract of employment is too vague to be pinned down with certainty, then the parties (or one of them) are in danger of the contract being ruled as non-existent. The common law insists that there should be "agreement" which is meaningful on both sides. Therefore the parties cannot state, as was done in one case at the turn of the century that an actress was to be hired at a 'West End salary to be mutually arranged." As the parties failed both to settle a salary and subsequently to enlighten the judge as to what they understood by the phrase, the contract was declared void. Nothing, it may be added, would have prevented the parties asking a third party to decide upon a figure. They were not obliged to fix upon a particular amount as the salary, as long as there was some process whereby it could ultimately be with certainty.
be reasonably ascertainable