The Big Bang Theory season 8, episode 12 was full of humor, but also touched on some of the deeper currents in the geeky gang’s lives.

It must be said that the overall plot of the episode wasn’t the strongest. The main action of “The Space Probe Disintegration” played like a sitcom from the 1950s, with Sheldon and Leonard dragged along on Amy and Penny’s girly activities. The idea of the guys sitting and holding the girls’ purses as they tried on clothes may paint a funny picture, but it’s too far from most people’s reality to land any real laughs.

But that was okay, as it turned out. The Big Bang Theory season 8, episode 12 was more focused on raising the temperature on a plot line that has been percolating since the end of last season – Sheldon and Leonard’s friendship, and what Leonard’s engagement means for the contractually-bound roommates.

The guys confronted the issue as they patted themselves on the back for compromising with their girlfriends – and then Sheldon patted himself on the back for compromising so unceasingly with Leonard.

Sheldon has matured incrementally over the years on The Big Bang Theory, but most of his baby-steps have been related to Amy. Sheldon’s matter-of-fact confession of love earlier this season was, truthfully, most of the development we expected to see from Dr. Cooper this year.

But the show does feature moments of appreciation between the self-centered scientist and Leonard, and we were probably due for an update on the state of their friendship. Sheldon’s acceptance of the fact that Leonard deeply wants to live with Penny is a significant milestone, and we’re very curious to see how the gradual apartment shifting plays out through the rest of the season.

…and to see if Amy tries to move in with Sheldon again. “If at first you don’t succeed,” girl!

“The Space Probe Disintegration” also focused on a very different kind of relationship – the interplay between science and faith. (We know, we were surprised too.)

Though the subject of spiritual beliefs has been raised before on The Big Bang Theory, the topic is usually treated lightly. But Thursday’s episode took the gloves right off, as Raj explained his religious faith to an incredulous Howard.

There were still plenty of jokes, of course. (Brisket! Blue arms! Ha ha ha.) But The Big Bang Theory then went directly to the heart of the matter, as Howard challenged Raj on employing two different rubrics through which to understand the world.

Raj then gave Howard a brief run-down on his faith, the great universal pattern, and the unity of life. Sure it was interrupted by a ding on the car door, but Raj’s speech was still arguably the deepest The Big Bang Theory has ever gone on the subject of religion.

It was a little bit weird to hear and see the sober topic raised with such a serious tone on the comedy, but in reality, the balance between science and faith is something that many modern scientists deal with. Though unexpected, we have to applaud The Big Bang Theory for being willing to tackle such a weighty subject.

The Big Bang Theory season 8 airs on Thursdays at 8:00 p.m. on CBS.

Were you moved by the emotions on ‘The Big Bang Theory’ season 8, episode 12?