This is the monologue for the latest episode of Why? Radio “Are there too many people for our environment?” with guest Philip Cafaro. You can hear the whole episode online here.

North Dakota is the nineteenth biggest state in the U.S. It is roughly the same size as Washington and it is bigger than Florida. But while Florida houses nineteen and a half million people and Washington has seven million, North Dakota has only about 700,000. If you plan even a little bit, you can go a long time without seeing anyone else.

This freaks my mother-in-law out. She’s from North Carolina, a smaller state with a much larger population. When she walks around Grand Forks, she likes to ask where all the people are, and my wife always responds “these ARE all the people, Mom.”  Yet even with its smaller size and ten million people, North Carolina still has plenty of places where you can hide. Eric Rudolph, the fugitive Olympic Park bomber, lived in the Appalachian Mountains for five years before he was apprehended.

So, with all of this said, it may seem odd to have a discussion about overpopulation, or, rather, it may seem strange to assume that it’s an American problem. Sure, if we look at pictures of Karachi or Mumbai we can see it, but that’s not here. That’s there.

There are two responses to the skeptics, but the first is bizarrely unpersuasive. We only have one world, and a problem for one person is a problem for everybody. Why do I call this bizarrely unpersuasive? Because it’s true and we should care, but we don’t. America still feels large, open, and available, and since we don’t experience it as crowded, we don’t act.

Philosophers remind us that justification is different than motivation; that just because we know something is true doesn’t mean we’ll act on it. We all understand that cigarettes will kill us, but people smoke anyway. You can lead a horse to water, but you can’t make him drink, and as a result, environmentalists have two different jobs, to persuade us that they are right and to inspire us to do something about it. But these are very different skill sets and they are usually found in very different groups of people. Here, a philosophical problem is intensified by a practical one.

The second response to skepticism about overpopulation is to prove our perceptions wrong, to get us all to doubt our experience of our country as abundant. How can America have too many people if our states have so much land? Here, the problem is that the term “overpopulated” is ambiguous. We need an independent standard to tell us how many is too many and that is what our guest today will offer. He is going to claim that empirically, objectively, our environment simply cannot sustain the next generation. There aren’t enough resources, there is tremendous natural devastation, and there is less and less wilderness every day. If we don’t lower the population, he’s going to insist, we are all doomed.

I suspect, however, that even our most open-minded listeners will resist his position because there is an even deeper motivation to look away. Accepting facts also means embracing moral responsibilities. Philosophers have shown us time and again that once we identify a moral wrong, we are obligated to fix it. This is why the U.S. Government rarely uses the term genocide, because once it does, we have to protect the victims. This is also why so many people refuse to say they are sorry after they hurt someone; once they apologize, they have to make up for the pain.

The same is true of overpopulation. Once we accept that it’s real, we are faced with some very serious questions about immigration and refugees, about contraception and abortion, about consumption and inequality. And once we ask those, we’re faced with even more intimate dilemmas. Which one of our friends do we wish hadn’t come to this country? Which one of our kids do we wish weren’t born? Of course, we can’t rewrite the past, but those unwelcomed new Americans, those children that were never conceived, they feel real. They are sacrifices. And maybe this is why so many people refuse to accept that human-caused climate change is real. Once we do, we have to fix it, and fixing it feels way too hard and way too disruptive.

The thing is, there is a case to be made that overpopulation trumps everything else, even individual rights. The democratic world has spent much of the last two centuries arguing for the integrity of each individual, but environmentalism may turn us all into utilitarians. It may force us to consider the needs of everyone collectively before we concern ourselves with particular people. So overpopulation is not just a practical problem, nor is it simply political. It is a philosophical dilemma that requires shifting our moral point of view, and that is never easy, even when we have no choice.