As the noted philosopher Donald Rumsfeld said, there are known unknowns (the things you know you don't know) and unknown unknowns (the things you don't know you don't know). When the former secretary of defense issued those words of wisdom just before the Iraq War, the phrase was remarkable not just for its pithiness but because it seemed unusually thoughtful for an administration about to embark on the greatest catastrophe in American foreign policy history, largely because of what it thought it knew but actually didn't.

Today we stand on the verge of a new presidency, one that has a complex and, to be frank, rather appalling relationship to knowledge and certainty. The implications are deeply troubling.

In Donald Trump, we may never have seen a political figure who more easily blended his own certainty with a contempt for the knowledge of others and the belief that knowledge itself is largely irrelevant to making vital decisions. It may have had a rational basis for a candidate running with zero relevant experience, but throughout the campaign, Trump poured contempt on the idea that knowing about things like policy and how government works might be useful for a president. "I know more about ISIS than the generals do, believe me," he said. He didn't need to seek counsel on foreign affairs because "I have a very good brain and I've said a lot of things." And in an interview on Sunday, he said he isn't bothering to receive daily intelligence briefings like previous presidents did, because "I'm, like, a smart person."

So Trump knows all. Yet at the same time, he tries to convince the public that there's almost no such thing as truth. He lies constantly, of course, dismissing any evidence contrary to the position he's taking at a particular moment as nothing but the product of dishonest media or his partisan opponents. He'll even say something, then tell you he never said it. Simultaneously, he tries to convince the public that we live in a land of the unknowable. Did Russia hack Democratic email accounts for the purpose of helping him get elected? "There's great confusion. Nobody really knows," he says. What about climate change? "I'm still open minded. Nobody really knows."

As Trump's subjects we may be stumbling through this fog of unknowing, but he himself is absolutely convinced that his own knowledge and wisdom is perfect, and no one has anything to teach him no matter how much expertise they might claim to have.

This probably has something to do with Trump's embrace of conspiracy theories. Over the course of the campaign and for years before, Trump publicly toyed with literally dozens of insane conspiracy theories, from birtherism to the Clintons killing Vince Foster to Ted Cruz's dad killing JFK to climate change being a hoax invented by the Chinese to the idea that the IRS was auditing him because "I'm a strong Christian." The hallmark of the conspiracy theorist is his belief that while others are being duped, he possesses the real and true information. He alone grasps the hidden structures of power and influence. That's the great attraction of conspiracy theorizing: It convinces you that nobody else gets it, they're all naïve sheep, but you are the one who truly understands the world as it is.

Perhaps Trump is rejecting the intelligence briefings because what the analysts tell him is too mundane. You'd think that like previous presidents he'd be eager to learn what's really going on, and what the classified information to which he never had access before might tell him. But maybe he was disappointed to learn that George Soros is not in fact holed up in a hollow mountain lair with other members of the global conspiracy working on a death ray with which they'll blackmail the world.

Trump is surrounding himself with those of a similar mind. His pick for national security adviser, Michael Flynn, has spread rumors that Hillary Clinton is involved in a pedophile sex ring, that Sharia law is taking over America, and that Clinton's campaign chairman John Podesta participates in Satanic rituals. And over the weekend, John Bolton — rumored to be up for the number 2 spot in the State Department — said that contrary to what intelligence agencies had concluded, maybe it wasn't even Russia that did the hacking. "It is not at all clear to me just viewing this from the outside, that this hacking into the DNC and the RNC computers was not a false flag," he told Fox News. Could it have been not the Russians at all but another country, or even the Obama administration itself, that did the hacking in order to blame Russia? Who knows.

This is shaping up to be a president and an administration that not only thinks they know what they don't actually know, but won't accept what they ought to know. And the contrast with the president Trump is replacing could hardly be more stark. One of Barack Obama's most important intellectual traits is his high tolerance for ambiguity and uncertainty. Unlike some of his predecessors, Obama is eager to admit that there are some things we struggle to predict, that we might be wrong, and that our decisions could produce unintended consequences. He'll be bookended by two presidents — George W. Bush and Donald Trump — who divided the world into black and white, good guys and bad guys, without entertaining the possibility that there are important shades of grey and things might not work out like we planned.

One could argue that at times Obama was too cautious, too concerned with what he didn't know or could not be known. But now we'll find out what it's like to have a president who thinks he knows everything, even as he knows almost nothing.