“In the old days, a liberal and a conservative (a “dove” and a “hawk,” say) got their data from one of three nightly news programs, a local paper, and a handful of national magazines, and were thus starting with the same basic facts (even if those facts were questionable, limited, or erroneous). Now each of us constructs a custom informational universe, wittingly (we choose to go to the sources that uphold our existing beliefs and thus flatter us) or unwittingly (our app algorithms do the driving for us). The data we get this way, pre-imprinted with spin and mythos, are intensely one-dimensional.”