Investors hate uncertainty. They place their bets based on expectations about how events will unfold, and when those expectations are suddenly and radically upended, they tend to get nervous and take their money off the table, especially if the event was completely unforeseen and wildly disruptive. Because most external shocks to the system do not threaten the basic foundations of the American economy, most of these gyrations are short-lived, and savvier investors pay them no heed at all, recognizing a difference between the signal and the noise. Some events might generate a great deal of political handwringing but still be irrelevant in the long run.

Of course, investors do not have a crystal ball, and so their models build in a certain tolerance for different outcomes. They cannot predict that a particular event—say, a hailstorm in Kansas—will happen on a particular day, or how severe it will be, but they can bet with some confidence that Kansas will get its fair share of severe hailstorms during the season, and when they arrive, no one is much alarmed, even if any given storm is especially severe and causes a great deal of localized damage. This is simply the distinction between the anticipated and unanticipated unknown.

All of this means that the reaction of the market often provides an especially clear window into what at least one group of people—investors—consider “normal,” or at least, unremarkable. If the market pays no attention to a particular episode, it is because investors consider it within the normal range of events that, ultimately, have no effect on American economic life. An event might matter a great deal to the people touched by it, but their concerns are local and ephemeral, or so the market calculates. This too shall pass. In the vernacular, the market has priced it in, meaning the event has no effect on valuations because it is within the range of expectations.

This assessment about the effect of an event is not simply a prediction about the day-to-day fate of the 30 businesses that make up the Dow Jones Industrial Average, or even the 500 in the S & P, or the more than 3300 in the NASDAQ. Businesses sell goods and services—at least, most of them do—and predictions about the market are, in the final analysis, predictions about mass behavior. When investors say the market, as a whole, will rise (or fall) they are making an assessment that consumers will (or will not) shop and buy and build and travel and have children and send their kids to college and move to new neighborhoods, and do all the things in their life that cost money. So their predictions are also judgments about the national mood—about the amount of confidence and hope consumers have in their future, and whether a particular event is likely to upset that confidence or diminish that hope. And this is not a trivial judgment; roughly half of all Americans are invested in the market.

I was thinking about all this as I reflected on the following:

On Sunday, October 1, 2017, Stephen Paddock gunned down nearly 5 dozen people and injured more than 500 others from his lair in a Las Vegas hotel room. The next day, the Dow Jones Industrial Average climbed 152 points. The day after, it added another 84.

On Tuesday, October 31, 2017, Sayfullo Saipov plowed a truck into a crowd in lower Manhattan, killing eight people and seriously injuring about a dozen others. The next day the Dow rose 58 points. The next day, it climbed another 81.

On Sunday, November 5, 2017, Devin Patrick Kelley shot and killed 26 worshippers in a white clapboard church in Sutherland Springs, Texas. Another 20 were injured. When the market opened the next day, it climbed seven points. It added another nine Tuesday, and six more on Wednesday.

Three mass murders in five weeks. More than ninety people killed. Six hundred injured. Saipov is unusual in that his weapon of choice was a truck. Of the three, he also killed the fewest people. Between the rampages by Paddock and Kelley, the US Centers for Disease Control estimates that more than 3,300 people were killed by guns in this country. Another 93 will be killed the day this column appears. And again the next day, and the next. From the Friday before Las Vegas to the Monday after Sutherland Springs, the Dow rose over 1140 points. The NASDAQ and S & P posted comparable gains.

I’m not sure what it says about us that we have priced in the expectation of such extraordinary carnage. In the United States, human destruction on a scale like this has absolutely no impact on national life. We apparently believe we can absorb this trauma indefinitely, day after day, for the rest of our lives, or so the market tells us. No, I’m not at all sure what it says. But I’m certain it’s not good.