President Donald Trump’s penchant for out-and-out deception—lies, in common parlance, and as more and more observers are willing to label them—has meant that another of his tendencies has been eclipsed: the tendency to bluff blithely and obviously falsely. During his trip to Asia over the past few days, however, Trump has made that tendency unavoidable, offering blusteringly confident answers to questions on topics he clearly knows nothing about.

The philosopher Harry Frankfurt offers an earthy, useful description of this mode of Trump speech in his essay On Bullshit:

He is neither on the side of the true nor on the side of the false. His eye is not on the facts at all, as the eyes of the honest man and of the liar are, except insofar as they may be pertinent to his interest in getting away with what he says. He does not care whether the things he says describe reality correctly. He just picks them out, or makes them up, to suit his purpose.

Consider Trump’s press conference in Osaka, Japan, on Saturday. A reporter asked Trump about a heated exchange between the Democratic presidential candidates Joe Biden and Kamala Harris at last week’s debate on the topic of school integration: “Where do you stand on that issue of federally mandated busing?” Trump first graded the debate on style, then added, “And as far as that, I will tell you in about four weeks, because we’re coming out with certain policy that’s going to be very interesting and very surprising, I think, to a lot of people.”

That seemed highly unlikely, so another reporter followed up:

Trump: Well, it has been something that they’ve done for a long period of time. I mean, you know, there aren’t that many ways you’re going to get people to schools. So this is something that’s been done. In some cases, it’s been done with a hammer instead of velvet glove. And, you know, that’s part of it … It is certainly a primary method of getting people to schools. Reporter: And is it—does it relate to the policy that you’re going to unveil that you just floated? Trump: It relates to everything we’re doing. And you’ll be hearing about it in—over the next couple of months.

Two things are clear: First, Trump has no idea what he is talking about. Second, Trump will not have a plan for busing, whether in four weeks or in two months. It’s not that he didn’t watch the debate, and for a moment, the president seemed to come close to grasping the conflict over school integration (“In some cases, it’s been done with a hammer instead of velvet glove”), but for the most part, he betrays no grasp of the complicated issue of busing. If he did, he wouldn’t be promising a plan, because it’s almost impossible to imagine any federal plan that would be in keeping with this political ideology.

Read: ‘If you want, I’ll go on’: Trump’s rambling news conference

Another similar moment occurred at the end of the press conference, when a reporter asked Trump about Russian President Vladimir Putin’s judgment that “Western-style liberalism” is obsolete. Putin was, of course, referring to the idea of republican governance developed in Europe and America. This is language that would be familiar to Trump’s former adviser Steve Bannon. Trump, however, apparently believed it referred to governments on the West Coast of the United States:

Well, again, he may feel that way. I mean, he sees what’s going on. And I guess, if you look at what’s happening in Los Angeles, where it’s so sad to look; and what’s happening in San Francisco and a couple of other cities which are run by an extraordinary group of liberal people—I don’t know what they’re thinking.

It is not merely that Trump is ignorant of issues about which one expects the president of the United States to be at least somewhat literate—though that is clearly the case. By promising a plan in four weeks, or baiting Bay Area liberals, Trump is attempting to hide his ignorance in the face of questions he does not understand.

The bigger problem is that Trump’s answer is obviously false, Trump knows that it’s obviously false, and he doesn’t care. (“It relates to everything we’re doing,” is one of Trump’s tells, a claim that is both so grandiose and so lazy as to reveal what’s actually happening.) This is what makes it “bullshit,” in Frankfurt’s sense, rather than simply lying. He is just making things up to suit his purpose. The proof is that he does this repeatedly.

As Frankfurt notes, these situations are an occupational danger for people in prominent jobs:

The production of bullshit is stimulated whenever a person’s obligations or opportunities to speak about some topic are more excessive than his knowledge of the facts that are relevant to that topic. This discrepancy is common in public life, where people are frequently impelled—whether by their own propensities or by the demands of others — to speak extensively about matters of which they are to some degree ignorant.

One can see this happening on cable TV on an hourly basis, as professional talkers are asked to talk about topics in which they have no expertise. Politicians tend to be made of slightly more prudent stuff, and when they get a question on an unfamiliar subject, they’ll offer some sort of vague nonresponse or vow to get back to their questioner later, often without any intent to follow through. Trump, who often acts more like a pundit than a president, is happy to follow the talking heads here as well.

In June, the president visited the United Kingdom, where his ambassador had recently created a controversy by saying the National Health Service should be opened up to American companies in a post-Brexit bilateral trade deal with the U.S. A reporter asked Trump whether he agreed. The president first tried to play it off—“I can’t hear him. What?”—until Prime Minister Theresa May threw a lifeline to her counterpart, who did not know the initialism NHS. “It’s a question about the National Health Service,” she explained. Trump jumped right in:

Look, I think everything with a trade deal is on the table. When you—when you’re dealing in trade, everything is on the table—so, NHS or anything else. There are a lot—a lot more than that. But everything will be on the table, absolutely. Okay.

Another of Trump’s tells for bullshitting is the promise of a forthcoming plan in some short, defined period. In 2017, Axios compiled a list of Trump promising to do things in two weeks’ time, often in response to questions for which he was unprepared. From that vantage point, his more modest promises on the busing plan—he’d release it in four weeks, or in a couple of months—represent a sort of growth.

But such promises remain politically risky. Even if Trump initially had no intention of releasing most of these two-week plans, his claims often elicit later questions from the press, chiefly, “Well, where’s the plan?” That, in turn, leads Trump to push out half-baked, hasty policy announcements on everything from tariffs to transgender troops.

Sometimes Trump’s instinct to bullshit makes the press his unwitting accomplice. During the 2016 presidential campaign, a reporter asked Trump whether he was proposing a registry or database of Muslims. The candidate at first answered noncommittally: “We’re going to have to look at a lot of things very closely.” By later in the same day, the question had become his policy: “There should be a lot of systems, beyond databases. We should have a lot of systems,” he said. When another journalist asked how that was different from Nazi registries of Jews, Trump replied, “You tell me, you tell me. Why don’t you tell me.”

Read: Is Donald Trump serious about registering Muslims?

As a group, the media seem to have no idea what to do with Trump’s comments when he speaks in this mode. Statements like those made in Osaka are immediately legible as phony to anyone paying close attention. Yet they can still carry great weight because they come from the president, just as they could very easily be forgotten immediately. Voters deserve to understand when the president is saying silly things. Trump has fueled a cottage industry of fact-checkers who point out his demonstrable lies, but reporters haven’t figured out how to respond when Trump is simply bullshitting.

Frankfurt explains why being able to label this behavior is more than idle taxonomy:

Someone who lies and someone who tells the truth are playing on opposite sides, so to speak, in the same game. Each responds to the facts as he understands them, although the response of the one is guided by the authority of the truth, while the response of the other defies that authority and refuses to meet its demands. The bullshitter ignores these demands altogether. He does not reject the authority of the truth, as the liar does, and oppose himself to it. He pays no attention to it at all. By virtue of this, bullshit is a greater enemy of the truth than lies are.

Of course, Trump is both the liar and the bullshitter, defying this binary. His lies have garnered a great deal of attention, even though voters are accustomed to the idea that politicians are dishonest, because of their brazenness and frequency. If Frankfurt is right, however, the greater peril comes not from Trump’s lies. His bullshit is the bigger enemy of the truth.