I had a talk with a professor of family law and we are frequently told that there are general ordinances for contracts in general and particular ordinances for marriage.
I am problematised by the logic. The general ordinances are only in vigour under the condition that there is no contrasting lex specialis, a contrasting particular ordinance.
So I thought that would lift the generality of the general provisions. They are particular in that they do not hold for all contracts but only for any contracts that are not marriage.
But I was told that the analogy to Euclidean geometry (everything that holds for rhombi necessarily also holds for squares) is inapplicable. Nonetheless, logic and set theory still hold in law as stated by the Professor.
My question: Does logic and set theory allow for properties holding for all members of a set (something which I identify with generality) not to hold for a particular subset?