After distinguishing one from three, it would be a mistake to assume that an intention of two is effective in exactly the same way in every case. In the cited legal analysis, a dual number is neither merely the minimum instance nor automatically the entire genus.
The discussion includes a special case concerning a woman of enslaved status within historical legal doctrine. This illustrates that the legal capacity of the subject matters along with the numerical expression.
The underlying distinctions are:
1. Unrestricted wording may establish the minimum instance.
2. The full genus may sometimes be a possible meaning of the expression.
3. An intermediate number can require a distinct legal basis or specially qualified subject.
Hence wording, intention, legal subject, and consequence must be considered together, rather than using number alone as a universal rule.