"But it's always been interesting to me that there's some sort of window open that allows for it all to have been just a more nuanced simulation. I think there is a genuine appetite for something in Dexter, but whether it's an appetite for an authentic experience of humanity is one that I think is left somewhat open."
And though his is the voice that supposedly makes us privy to Dexter's thoughts, "I don't feel a hundred percent bound by what he says in the script or what he says in his voice-over narration," Hall said.
Not even now that Deb, too, knows what her foster brother has been up to all these years?
"I love that Dexter never in any genuine way says to Deb, 'I'm sorry,' " Hall said.
"He's immediately ready to defend himself. We're never going to see - I guess it's important to never say never - but I don't think we're ever going to see Dexter in a courtroom, going through a trial.
"But when that was a possibility, theoretically, I always thought it would be interesting to see him defend himself. And while he's not doing that in a courtroom, he does do it one-on-one with Deb. And he doesn't back away from how he's lived his life and the code that he has followed is one that in the light of day . . . he's perfectly ready to defend."
The character also uses Harry (James Remar) - the dead foster father we frequently see counseling Dexter in the same way he apparently did when he was alive - "to deflect some of Deb's dismay or rage. It's a completely justifiable thing to do, but it's also tactically something that helps Dexter maybe turn the heat down a little bit in terms of Deb's take on all of this," Hall said.
Carpenter's character has also at times seemed to understand a little of Dexter's point of view as she realized his vigilante code - he kills other killers - could accomplish things that she, a police lieutenant, couldn't.
"I think there are stages of grief. It's probably less documented, but there are probably stages of a sibling's reaction to discovering their brother's a serial killer," Hall said, laughing.
"That's what we see her go through [this] season, but I don't think she'll stay there," he added.
"All signs point" to Season 8 being the last and as far as Hall's concerned, the ending isn't just near for Dexter - it's already well under way.
"Once Deb finds out the secret, the show in its current form can't survive indefinitely and so I think once the sixth season ended with that final cliff-hanger scene, we felt like the wheels were in motion to move us to some sort of definitive end," he said.
He, at least, sounds ready for it. And Dexter may be, too.
"In playing that scene in the church, in the premiere episode of the seventh season, it was the first scene we shot when we returned to work and Jennifer and I both, I think, were struck at how, obviously, horrifying and stressful in very different ways it was for both characters, but there was also this underlying sense of relief. Whether consciously or unconsciously, this is a secret that they both had been keeping," Hall said.
For Dexter, the longing to be known for who he is - which earlier led him to get too close to the killer known as "Trinity" (John Lithgow) and this season to Hannah (Yvonne Strahovski) - "is really what gets him into trouble," he said. "That's sort of the tragedy of the character, I think."
The actor said he's often asked whether Dexter will "get away with it or will he be caught? And I think Dexter is really in the process of being slowly but surely caught already. I think he's caught by the realization that his behavior affects more than just his victims and how he reacts to and manages that is a part of what the show is about now.
"His powers of compartmentalization and denial and stress management are certainly off the charts, but I think he's coming to a place where he really can't deny the residual wreckage that his indulgences have created."
On Twitter: @elgray