DISSIMULATION. - In canon law it means the attitude of a superior who, though aware of a transgression of the law, pretends not to know of it. It is an essentially negative act. Whereas in tolerance the superior expresses his displeasure and outwardly makes it understood, indeed sometimes directly manifests by decree, the will "quod tolerari poterit," in dissimulation he prefers to ignore and to be recognized as ignoring. Hence the distinctions: dissimulation determines rather an attitude of the superior of a provisional character, imposed by unavoidable or difficult-to-remove contingencies, having, however, juridical consequences, in the sense that it does not permit, in foro externo, that proceedings be taken against the transgressor, either ex officio or at the instance of a party; dissimulation does not remove the obligation and, under current legislation, does not entail dispensation, as instead in the times of Lucius III and Innocent III it was held by some, especially with regard to matrimonial impediments, according to the formula "dispensando dissimulat et dissimulando dispensat."
Tolerance, on the other hand, does not merely indicate an attitude of the superior, but can sometimes indicate a stable juridical condition with a permissive faculty of acting against the law and with the obligation for others not to impede, within the terms of the concession (cf. can. 5 of the CIC, for tolerance with regard to custom).
Both dissimulation and tolerance are negative acts to which authority is almost constrained, for a higher purpose.
In moral theology the term dissimulation is sometimes taken to indicate simulation improperly so called (v. SIMULAZIONE).
Bibliography3 works
Enrico M. Zanetta