Life is vastly better for African Americans than it once was. But nothing fundamental has changed for African Americans.

How can both statements be true? A cryptic line in Book 5 of Aristotle's Politics explains it. Discussing the problem of factional clashes that can lead to political unrest and even revolution, Aristotle remarks that the source of such conflicts can often be found in an "error" that takes place "at the beginning" of a political community's history — at a time when "even a small error" takes on outsized importance for everything that follows.

Aristotle's insight has major implications for America's fraught history of race.

Consider the L.A. riots of 1992, sparked when a jury in Simi Valley, California, failed to convict four police officers who'd been caught on video encircling Rodney King, an unarmed black motorist, and brutally beating him with batons. Soon L.A. was burning, with much of the mayhem filmed from the air by helicopter, allowing the rest of America to observe the violence live, from a safe, judgmental distance.

That's certainly how I viewed it: The acquittals of the cops were unfortunate, but the riots were just not a reasonable response.

But then something touched a nerve: A news helicopter caught a group of black men swarming around a truck, pulling the white driver from the cab, and beating him. Before long, one of the assailants hurled a brick into the driver's face at point-blank range and then broke into an exultant dance. Seeing this vicious assault live on TV, I exploded in fury, screaming impotently at the injustice I'd just witnessed. How dare these criminals attack an innocent man just because of the color of his skin! Who the hell did they think they were? Send in the cops! Call up the reserves! Declare martial law!

The anger clung to me all afternoon and was still weighing me down when I arrived that evening at NYU, where I was a first-year graduate student, for a political theory review session I was supposed to lead with another, more advanced grad student. It wasn't long before an undergraduate brought up the riots in the midst of a conversation about Aristotle. What would the philosopher say about the unrest? I knew how I wanted to answer: Aristotle would talk about the importance of the rule of law and securing the common good, one element of which is domestic peace and order.

Instead, my older colleague brought the class to a much deeper point. Directing the students to the passage about an error baked into a political community's founding, he asked them if that line provoked any thoughts about American history. Of course, they answered: slavery.

And what did it mean to think about slavery in light of Aristotle's suggestion? Before long the class was discussing the difficulty of righting such a profound injustice once it's been embedded in the political community's founding documents, laws, institutions, habits, customs, and history — how all of them can act as a form of human inertia, pulling the community back time and time again to old patterns and ways and thinking and acting, continually reinforcing old divides and tendencies even as the community attempts to change and improve down through the years, decades, and centuries, with the Rodney King beating and verdict, the cruelly joyful attack on the white truck driver, and the dramatically different response of black and white Americans to both acts of injustice just the latest examples.

The students were right — and so was Aristotle.

This is as apparent as ever today, with graphic videos showing Alton Sterling and Philando Castile dying at the hands of the police in Louisiana and Minnesota. African Americans are no longer slaves. The law no longer systematically and explicitly treats them as second-class citizens. A majority of American citizens have twice voted to elect an African American president. All of that is real and important and points to real long-term change for the better.

But are blacks truly treated as equals in the United States in 2016? The answer is undeniably no — especially when it comes to law enforcement.

And perhaps even worse than that is the lack of equality in how white and black Americans respond to this reality.

Let's put aside the details of the Sterling and Castile shootings. Investigations are ongoing, and there's no point in pretending to know more than we do about exactly how and why both men ended up dead. I just want to focus on one fact that's been reported about Castile. In recent years, he'd apparently been pulled over 52 times by police in the Twin Cities area. (The Washington Post also reports that he'd been "assessed at least $6,588 in fines and fees, although over half of the total 86 violations were dismissed.")

You know how often I've been pulled over by the police in the 30 years since I received my driver's license? Fewer than half a dozen times. Each time it was because I'd committed an infraction — speeding, busted tail light, rolling through a stop, going through a light just as it turned red. On a few of those occasions, the cop let me go without a ticket. Never once did I fear I'd be arrested and thrown in jail, let alone that I'd end up dead. And my expectation was entirely reasonable. Because I'm white and tend to live in majority-white middle- and upper-middle-class neighborhoods, and that kind of thing simply doesn't happen to people like me in places like that.

I usually feel safe. And when I don't, it's because of crime, not because of the police, whom I usually trust will protect me and those I love.

How many African Americans can say that?

In the mostly white Philadelphia suburbs where I live, the police frequently pull over motorists on busy Lancaster Avenue. More often than not, the driver is black. I don't know if the local police actively practice racial profiling, or if they're acting on a subconscious suspicion of blacks, or if African Americans just happen to break traffic laws far in excess of other drivers. Whatever the reason, blacks end up having much more frequent interactions with law enforcement — and those interactions more often end up going wrong.

That's what the data appear to show — both that African Americans are disproportionately the victims of violence (though perhaps not lethal violence) in their encounters with armed agents of the state, and that officers perceive a greater threat when encountering an unarmed African American, making them more likely to resort to force.

It's an intolerable situation — at least for blacks. For whites? Yes, it's a problem, but also one much more easily forgotten, grudgingly accepted, or explained away. That certainly explains my reaction to the Rodney King verdict 24 years ago. It's bad, I thought. But not something to infuriate me. Unlike the similarly arbitrary act of unjust violence committed against the white truck driver. That was the real outrage. Or so it seemed to me at the time. Not because of anything as refined as ethical reasoning or moral judgment. But because deep down I knew that I would never find myself in Rodney King's shoes — and that even though I had very little in common with a truck driver hauling a load through south-central L.A., I had enough in common with him that I could put myself in his place.

Because he was white.

In one case, my moral imagination functioned perfectly well. In the other, it failed me. I suspect a similar failure continues to shape the thinking and actions of many white cops, white prosecutors, white jurors, and white voters. However much we shake our heads and lament the deaths of Alton Sterling and Philando Castile (and Michael Brown and Laquan McDonald and Tamir Rice and Walter Scott and Samuel DuBose and Eric Garner and Freddie Gray), the mourning, the suffering, the injustice is simply felt less keenly on the white side of America's seemingly unbridgeable racial chasm.

We need to do better. Though in light of America's founding mistake, Aristotle would understand why we so often don't.