A common cause that precedes both events may fail to screen off the correlation between events in heavily overlapping regions

Now suppose that the regions A and B almost completely overlap, but neither is contained within the other (see Figure 5(b)). Again, the corresponding events A and B will be correlated, and the earlier common cause may not screen them off. (Arntzenius (1999 [2010: section 2.4]) has an example that has essentially this structure.) It seems that this case, too, is one in which the events A and B are insufficiently distinct. But now it becomes difficult to formulate a notion of distinctness that i