What does "capacity to contract" mean?

The concept of "capacity to contract" refers specifically to the legal ability of an individual or entity to enter into a binding agreement. This legal capacity is crucial because it determines whether the parties involved can understand and appreciate the nature and consequences of the contract they are forming. For instance, parties must typically be of a certain age (usually 18 years or older) and possess sound mental ability; those who are minors, mentally incapacitated, or under the influence of drugs or alcohol might lack the capacity to form a legally enforceable contract.

This definition underscores the importance of capacity because a contract entered into by someone lacking this capacity may be voidable or unenforceable in a court of law. The other options relate to different aspects of contract law: modifying terms, the requirement of writing, and proving contracts in court, which do not directly address the foundational legal ability necessary to make contractual commitments.