Beyond the sheer mental workload, our thoughts have acquired a new orientation. Of the two mental worlds everyone inhabits, the inner and the outer, the latter increasingly rules. The more connected we are, the more we depend on the world outside ourselves to tell us how to think and live. There’s always been a conflict between the exterior, social self and the interior, private one. The struggle to reconcile them is central to the human experience, one of the great themes of philosophy, literature, and art. In our own lifetime, the balance has tilted decisively in one direction. We hear the voices of others, and are directed by those voices, rather than by our own. We don’t turn inward as often or as easily as we used to.