On Sunday, Austin’s interim police chief Brian Manley told reporters at a news conference that investigators thought there was a motive behind what was then a string of three bombing attacks; they just didn’t know exactly what it was.

“We believe that the recent explosive incidents that have occurred in the city of Austin were meant to send a message,” Manley told reporters. Then, he made a plea directly to the bomber:

“These events in Austin have garnered worldwide attention, and we assure you that we are listening,” Manley said. “We want to understand what brought you to this point, and we want to listen to you.”

The bomber’s answer came a few hours later with a new type of bomb set off by a trip wire he had placed in a different part of the city, suggesting a more random choice in victims. Then, early on Wednesday morning, with the police in pursuit, the bomber, identified as 23-year-old Pflugerville resident Mark Anthony Conditt, blew himself up in a ditch off Interstate 35.  That night, Manley once again appeared in front of cameras to say that, while authorities had recovered a 25-minute video “confession” from Conditt, the bomber’s intentions remained opaque.

“It is the outcry of a very challenged young man talking about challenges in his life that led him to this point,” Manley said. “I know everybody is interested in a motive and understanding why. And we’re never going to be able to put a [rationale] behind these acts.”

We're never going to be able to put a rationale behind these acts.

interim police chief Brian Manley

As soon as police announced that the multiple bombings likely had a single perpetrator, the question surfaced as to whether the attacks amounted to terrorism. If terrorism, a much-debated term, is broadly defined as an act of violence against civilians meant to incite fear and unrest in pursuit of a political aim, then the debate seemed to hinge on Conditt’s intent. When the first four victims were black and Latino, many wondered if the bomber had a racist political program. When the fifth and sixth victims turned out to be young white men in a predominantly white Southwest Austin neighborhood, the attacker’s motives looked murkier. Over the last several days, we’ve learned that Conditt wrote blog posts against gay marriage and abortion and in favor of the death penalty, that he described himself as a conservative who didn’t have “enough information to defend my stance as well as it should be defended,” and, most recently, that he had diagnosed himself as a “psychopath.”

The apparent randomness of Conditt’s targets and the lack of evidence so far that he was motivated by a specific agenda would seem to argue against classifying the bombings as acts of terrorism. But, in fact, public mass violence often doesn’t have a tidy explanation and clear motivations. Over the past half century, fewer and fewer perpetrators of terrorism have claimed responsibility for them. In the 1950s and ’60s, according to research by Austin L. Wright, an assistant professor of public policy at the University of Chicago, 80 to 90 percent of terrorist acts were claimed by an individual or a group. Over the past decade, this percentage has fallen below 20 percent.

“It’s a sea change, and it’s not entirely clear why you see this massive shift,” says Wright. “But there are all sorts of incentives to keep an attack ambiguous. In the case that you’re an individual, maybe you’re frustrated and maybe you feel that you need to do something, but you aren’t quite clear on what your goals are yet. You want to create unrest, but you’re still reckoning with why.”

Even bombers with a clear sense of purpose have often refused to publicize their motives. Timothy McVeigh didn’t admit that he was responsible for the Oklahoma City bombing until years after he was convicted and sentenced to death. Ted Kaczynski, the Unabomber, waited 17 years and 16 bombings before he sent his 35,000-word anti-technology manifesto, Industrial Society and Its Future, to the New York Times and the Washington Post. (The papers—at the urging of the FBI—then published Kaczynski’s screed, which led Kaczynski’s brother, who recognized the mysterious writer’s style and obsessions, to finger him as a suspect.)

McVeigh’s silence didn’t stop anyone from appreciating the political significance of his attack. He blew up a federal building on April 19, 1995, the second anniversary of the fire that consumed the Branch Davidian compound outside Waco. The militia movement had already used Waco as a rallying cry, seeing it as an act of mass murder perpetrated by the FBI. It didn’t take McVeigh’s admission—or even his arrest—to understand that the attack likely had warped political purposes.

Kaczynski’s motives, though, were harder to divine. In addition to sending bombs to scientists, he tried to blow up an airliner.  His targets for much of his bombing spree appeared random. The FBI couldn’t decide whether they were dealing with a neo-Luddite with a hard sciences degree or a blue-collar airplane mechanic. In 1995, when Kaczynski released Industrial Society and Its Future, his motives seemed to become clear: Kaczynski had intended to strike back against technology and some of the technologists who he thought had destroyed society.

But further discoveries complicated the picture. After Kacyznski pleaded guilty, in 1998, the government released more than 100 excerpts from his journals, among them a passage written at the beginning of his bombing spree in which he declared, “I emphasize that my motivation is personal revenge. I don’t pretend any kind of philosophical or moralistic justification.”

Did any of these revelations change anything? What would have happened if Kaczynski had died in an accident in his Montana cabin before he could send out his manifesto? Would his acts—which killed three people and injured twenty-two others—then not have been terrorism, but the work of a “very challenged man” whose intentions would forever remain unknown? And did Kaczynski’s journal entries showing his seething rage nullify the political program he put forth in Industrial Society and Its Future?

“Sometimes it’s difficult to draw lines between political, personal, and pecuniary motivations,” says David Schanzer, the director of the Triangle Center on Terrorism and Homeland Security at Duke University. “An individual may be motivated to violence due to deep personal grievances, but a shooting rampage targeting women, like the once that took place in Santa Barbara in 2014, can be so targeted and intimidating that it makes a political statement.”

We may well learn at some point—today, next week, in a decade—that a warped ideology led Conditt to unleash his attacks on the citizens of Austin. But it’s more likely that we won’t, that we’ll be left to wonder. This might mean that some will withhold the label of terrorism from it, but that’s ultimately a political choice when thinking about a string of violence like this one.

If Conditt had been found with a copy of the Qu’ran in his front seat—even if he had left the very same 25-minute confession—the conversations taking place on cable news right now would be quite different.

If Conditt had been found with a copy of the Qu’ran in his front seat and the very same 25-minute confession, the conversations taking place on cable news right now would be quite different. But exactly what message Conditt hoped to send is now irrelevant. He killed two members of Austin’s African-American community, and made its already embattled members feel less safe. His wave of bombings made all of us feel less safe. As Wright told me the day before Conditt was identified, “If the point is to incite a broader sense of fear, then you wouldn’t focus on one population, and you’d go from a parcel bomb to a trip wire. Why? Because a parcel bomb will almost certainly be opened by an adult, but a trip wire could be triggered by a child—it opens up a whole range of potential people who could be affected. These are IEDs. They’re meant to be indiscriminate.”

The randomness of Conditt’s attacks, the small-scale nature of his attacks, the cruelty of placing bombs in front of homes and in the middle of communities—all of that made for an intimate terror, one that made our front doorsteps feel less safe than a gathering of thousands at South by Southwest. This kind of violence was the message, just as the Unabomber’s violence, not his manifesto, was the message, and just as the violence perpetrated in those unclaimed terrorist attacks is understood, whether or not anyone gives a concrete “why.” Conditt spread fear and hate. That is the only message that matters.