Leonard, in the world
of THEORETICAL physics, you never finish.
The Big Bang Theory Season 10, Episode 15
...because he said
it was a THEORETICAL nut conflict.
The Big Bang Theory Season 8, Episode 21
So now let's bring out THEORETICAL physicist,
Dr. Sheldon Cooper!
The Big Bang Theory Season 6, Episode 18
Is it maybe because, like Sheldon's work,
your sex life is also THEORETICAL?
The Big Bang Theory Season 6, Episode 9
It's very impressive.
For THEORETICAL work.
The Big Bang Theory Season 4, Episode 3