If we can't yet even understand how a 2-year-old toddler—or for that matter a 2-day-old baby—thinks, machines that think like humans are probably many decades away. But once we do have machines that "think," what kind of thinking will they do? The answer will define future human societies.
As machines start thinking for real, drudgery will be the first thing to go; so long to tasks like daily cooking, grocery shopping, and an especially unfond farewell to house cleaning. Soon we may be back in a world in which the wealthy or the educated (with greater access to machines) once again have more leisure time.
If machines are one day capable of sophisticated human thinking, they might also be able to program our apps, do much of our work, and maybe even create our art for us.
But what would ordinary humans then do?
One gloomy possibility is that we become zombie consumers of a machine-run world straight out of an apocalyptic futuristic film noir.
A decidedly cheerier possibility is that we might spend this extra time doing the things we usually resolve to do. We might play with and teach our children more, get to know our parents better, and build stronger social networks out of actual flesh and blood. We might prioritize our hobbies, climb more mountains, and learn new skills, just for the joy of it. We could then focus our energies on the important issues that routine and minutiae too often push aside: living a good life, being our best selves, and creating a just world—for humans and for thinking machines.
If machines think like humans, humans will have to think hard about how we can bring about this latter possibility. Positive thinking alone is not going to get us there.