If you were in ancient Rome looking for signs of the big fall, you wouldn't look in the headlines. You'd have to look closely for small signs, faint signals. You'd have to keep watching day after day and year after year. That's roughly what Eric Schnurer argues in a long comment to a recent article in The Atlantic on Rome's slow fall, "Why Local Innovation Is the Answer." Small things, he writes, often have "large-scale effects but play out on the level of individual grains of sand."