From LH Morgan’s introduction to “Systems of Consanguinity and Affinity of the Human Family“:
The tables, however, are the main results of this investigation. In their importance and value they reach far beyond any present use of their contents which the writer may be able to indicate. If they can be perfected, and the systems of the unrepresented nations be supplied, their value would be greatly increased. The classification of nations is here founded upon a comparison of their several forms of consanguinity. With some exceptions, it harmonizes with that previously established upon the basis of linguistic affinities. One rests upon blood, the preponderance of which is represented by the system of relationship; the other is founded upon language, the affinities of which are represented by grammatical structure. One follows ideas indicated in a system of relationship and transmitted with the blood ; the other follows ideas indicated in forms of speech and transmitted in the same manner. It may be a question which class of ideas has been perpetuated through the longest periods of time.
It strikes me that I am working on both Morgan’s Question and Galton’s Problem.