Thank you for reading. This is a very difficult question. I am sympathetic to the view of Spengler, which is similar to that of Toynbee. But in practise, I th

Thank you for reading. This is a very difficult question. I am sympathetic to the view of Spengler, which is similar to that of Toynbee. But in practise, I think what constitues the West is constantly changing. The historical base is Western Europe. If Western Europe and the US diverge in ideology over the next few decades (not necessarily a bad thing) then as a category the West will shrink back to the base. Possibly a bit larger if the EU stays intact or integrates further, as I hope it does. If one was to scientifically determine it they would look at how strong cultural transmission is across the different units -- probably looking at the distribution of movies and other media, as well as how quickly new phrases and political ideas spread across social media.