To get to this college classroom, you have to walk past the barbed wire, between a line of armed guards, and through the heavy metal bars. Only then do you arrive at the circle of chairs.
When class starts, half the chairs are filled with so-called "inside students," men and women serving time behind bars. The other half of the seats are occupied by "outside students" — basically, traditional college students.
This coming year, more than 100 universities and colleges around the world will offer Inside-Out classes.
All of these classes are taught inside prison walls, but there's one cavernous auditorium that's something of a hub for the program. It's dotted with industrial fans and deep inside SCI Graterford Prison, about an hour's drive from Philadelphia.
"Look at the curtains," says Paul, an inmate serving a life sentence. "Them curtains don't look like they been washed in 100 years. But it's kinda a sacred space for Inside-Out."
Paul would know. This has been his classroom for years, both as a student and as a teacher.
Pennsylvania's Department of Corrections won't let us use Paul's last name, but they will let Paul train college professors on how to run their own Inside-Out classes.
Today, Paul is explaining this new type of student — the inside students — to a couple dozen professors.
"A lot of us came from worlds where we were isolated," Paul says into the microphone. "Almost like an underworld, our thoughts and our perceptions were in a cave of Plato."
If it's been a while since philosophy class, Paul is referring to Plato's Allegory of the Cave.
The ancient Greek scholar told the story of people held in chains. They watch shadows on the cave wall and those flickering images of the world are as close as they ever get to reality.
Paul says it's here, in the Inside-Out trainings and classes, that he escapes from Plato's cave, even if he's still inside a maximum-security prison.
Paul grew up in another version of Plato's cave: North Philadelphia.
It was a tumultuous world of poverty and gangs, and for Paul, the rest of America was just a shadow of reality.
"My family moved probably every three to six months," Paul remembers. "We lived in Seventh Street, Fourth Street, 17th Street ... " The list goes on.
For him, college wasn't an option. Instead, he'd walk longingly past the gas station.
"And I used to say, 'Oh I wish I can get a job like that with a uniform with my name on it.' And that was my highest aspiration."
Things didn't pan out. As a teenager, Paul fatally stabbed a member of a rival gang and, in 1977, he was convicted and sentenced to life without parole.
"My mission in life now is to leave a better legacy than the one I had left when I came to prison," Paul says.
Two decades ago, he had an idea for what that legacy could be.
Here's what happened: A group of students from Temple University were studying prisons. And, one day, Paul spoke to them. Before the 45 minutes had ended, Paul began to notice that his stereotypes of elite college students were beginning to fade. And vice versa. He started wondering about the power of dialogue.
"It humanizes people on both sides of these walls," Paul says.
Just as the class was ending, Paul asked the Temple University professor, Lori Pompa, whether the conversation had to end. What if it could last a whole semester?
Pompa says she felt the same way. "All I can say is that the conversation I had that day was one of the most powerful conversations I had had."
She began think Paul was on to something.
"What dialogue does is it helps to make the walls between us more permeable," Pompa says.
So, she got to work and did what professors do: design a class.
A few years ago, Cyndi Zuidema took the Inside-Out class as a freshman at Temple University. She says she'll never forget her first day.
"What are we going to talk about?" Zuidema recalls thinking nervously to herself.
Plenty, it turns out. So much that she ditched the idea of doing a Ph.D. or becoming a family counselor.
"After I took the class, I said: 'I'm just so passionate about these issues. This is what I want to do,' " Zuidema remembers. "Some of my greatest teachers were the men inside SCI Graterford — and Paul is one of them — so I carry that with me always."
Zuidema now works as a reentry coordinator for men and women who are released from prison.
While Paul will never re-enter society — he's serving a life sentence — he is working on his master's degree. And he says Inside-Out classes offer him a degree of freedom.
"It gives you the freedom to care again. The freedom to feel again."
It gives him the freedom to escape Plato's Cave and be part of reality — if only for an hour at a time.