The Causal Pathways of Johnny Cash

I am slogging my way through Steven Pinker's new and very thick book called The Better Angels of Our Nature: Why Violence Has Declined and it's worth the slogging; for example, after a densely statistical section on the civilizing influence of women in the Wild West, Pinker sums up with this bon mot: "When they held constant all the factors that typically push men into marriage, they found that actually getting married made a man less likely to commit crimes immediately thereafter . . . the causal pathway has been pithily explained by Johnny Cash: Because you're mine, I walk the line."