15 Underlying principles

For the broader purposes of the DCFR we suggest that the underlying principles should be grouped under the headings of freedom, security, justice and efficiency (rather than liberté contractuelle, sécurité contractuelle et loyauté contractuelle as in the Principes directeurs). This does not mean that the principle of contractual ‘loyalty’ is lost. To a large extent it is covered by the wider principle of justice, without which many of the rules in the DCFR cannot be satisfactorily explained. To some extent it is simply an aspect of contractual security viewed from the standpoint of the other party.15. One party's contractual security is increased by the fact that the other is expected to co-operate and act in accordance with the requirements of good faith and fair dealing. Nothing is more detrimental to contractual security than a contractual partner who does not do so: a cheating and untrustworthy partner, and even an uncooperative partner, may be worse than no partner at all. The heading of efficiency is added because, although this is often an aspect of freedom (freedom from unnecessary impediments and costs), it cannot always be accommodated under one of the other headings. These four principles of freedom, security, justice and efficiency are developed and illustrated at length in the section on underlying principles which precedes the model rules.