Recording the percentage of people who say they are happy will tell you something, to be sure, about how people use words. It’s worth learning. We cannot ever know whether your experience of the color red is the same as mine, no matter how many brain scans we take. (The new hedonism is allied, incidentally, with the new brain science, which merrily takes the brain for the mind.) Nor can we know what red or happiness 1-2-3 is in the mind of God, the “objective happiness” that Kahneman speaks of as though he knew it. We humans can only know what we claim to see and what we can say about it. What we can know is neither objective nor subjective, but (to coin a word) “conjective.” It is what we know together in our talk, such as our talk about our happiness. Con-jective: together thrown. No science can be about the purely objective or the purely subjective, which are both unattainable.

If a man tormented by starvation and civil war in South Sudan declares that he is “happy, no, very happy, a regular three, mind you,” we have learned something about the human spirit and its sometimes stirring, sometimes discouraging, oddity. But we inch toward madness if we go beyond people’s lips and claim to read objectively, or subjectively, their hearts in a 1-2-3 way that is comparable with their neighbors or comparable with the very same South Sudanese man when he wins an immigration lottery and gets to Albany.