Chapter 4 discusses how contract law affects consentability. Because a contract expresses a present intent to bind oneself to do something in the future, there always lurks the potential for a party to change her mind. But the very purpose of a contract is to ensure performance even when a party at a later time no longer wishes to perform. The binding nature of a contract means that it can be a double-edged sword as a tool for promoting autonomy. All contracts require consent, but not all consentable acts are – or should be – contractable Chapter 4 concludes that, in some cases involving autonomy, contract enforcement would pose harmful societal effects. This chapter examines contract law through the consentability framework and explains how consentability determinations are often based upon contractability.