"A matrimonial contract cannot validly exist between baptized persons unless it is also a sacrament by that fact". So runs canon 1055, § 2 of the 1983 Code reproducing literally canon 1012, § 2 of the pio-benedictine Code. This word-for-word reproduction is all the more striking in view of the many suggestions and efforts made over the twenty years of drafting of the new Code, to have this paragraph of the old canon 1012 changed. If the suggestions were not accepted in the end, this would seem to be because, while the pastoral concerns behind them were understandable enough, they were not held to correspond to sound theological (and therefore to sound juridic) thinking.
Rules of interpretation
I. Lack of authenticity: deceit or fraud in consent
In the case of simulation, the lack of authenticity in marital self-giving is evident. The person going through the ceremony does not give himself conjugally. There is a constitutional lack of integrity in the marital donation made to the other.
Incapacity for giving valid matrimonial consent, deriving from some notable defect of the person's psychic faculties, is dealt with in c. 1095 of the 1983 Code: "They are incapable of contracting marriage: 1º who lack sufficient use of reason; 2º who suffer from a grave lack of discretion of judgment concerning the essential matrimonial rights and duties which are to be mutually given and accepted; 3º who are not capable of assuming the essential obligations of matrimony due to causes of a psychic nature".