Wilczek replies: Each correspondent has a valid point. I enthusiastically agree with Marcia Bjørnerud: The nonuniversal problems that arise in describing our specific place in the world are not only valid but often fascinating and important. I was building toward this major point in the entire series, and it was emphasized explicitly in the final sentence: “Such necessary concessions to reality compromise the formal purity of the ideal of understanding the world by analysis and synthesis, but in compensation, they allow its spirit much wider scope.”

I also agree with Joe Lacetera, though more reservedly. The idea that the statistical aspect of quantum theory might reflect our incomplete comprehension of an underlying deterministic theory has had some extremely eminent champions, from Albert Einstein at the beginning to Gerardus ’t Hooft today. It is a difficult program, however, since the success of quantum theory is broad and deep, especially in the atomic and subatomic realms. I’d be more optimistic about finding surprises in the recent, promising, but relatively poorly tested application of quantum theory to cosmology, as I mentioned in the column: “We can test the hypothesized quantum origin of primordial fluctuations by checking whether those fluctuations satisfy statistical criteria for true randomness.”