Whether consanguinity is fittingly distinguished by degrees and lines?
Objections
❌ Objection 1 : It would seem that consanguinity is unfittingly distinguished by degrees and lines. For a line of consanguinity is described as "the ordered series of persons related by blood, and descending from a common ancestor in various degrees." Now consanguinity is nothing else but a series of such persons. Therefore a line of consanguinity is the same as consanguinity. Now a thing ought not to be distinguished by itself. Therefore consanguinity is not fittingly distinguished into lines.
❌ Objection 2 : Further, that by which a common thing is divided should not be placed in the definition of that common thing. Now descent is placed in the above definition of consanguinity. Therefore consanguinity cannot be divided into ascending, descending and collateral lines.
❌ Objection 3 : Further, a line is defined as being between two points. But two points make but one degree. Therefore one line has but one degree, and for this reason it would seem that consanguinity should not be divided into lines and degrees.
❌ Objection 4 : Further, a degree is defined as "the relation between distant persons, whereby is known the distance between them." Now since consanguinity is a kind of propinquity, distance between persons is opposed to consanguinity rather than a part thereof.
❌ Objection 5 : Further, if consanguinity is distinguished and known by its degrees, those who are in the same degree ought to be equally related. But this is false since a man's great-uncle and great-nephew are in the same degree, and yet they are not equally related according to a Decretal (cap. Porro; cap. Parenteloe, 35, qu. v). Therefore consanguinity is not rightly divided into degrees.
❌ Objection 6 : Further, in ordinary things a different degree results from the addition of one thing to another, even as every additional unity makes a different species of number. Yet the addition of one person to another does not always make a different degree of consanguinity, since father and uncle are in the same degree of consanguinity, for they are side by side. Therefore consanguinity is not rightly divided into degrees.
❌ Objection 7 : Further, if two persons be akin to one another there is always the same measure of kinship between them, since the distance from one extreme to the other is the same either way. Yet the degrees of consanguinity are not always the same on either side, since sometimes one relative is in the third and the other in the fourth degree. Therefore the measure of consanguinity cannot be sufficiently known by its degrees.