
They were probably up all night
coming up with a new THEORY.
The Big Bang Theory Season 12, Episode 9

Actually, I would like
to explain my THEORY to you.
Money Heist Season 1, Episode 8

I guess we wait until they're old enough
and let them choose their own THEORY.
The Big Bang Theory Season 2, Episode 2

called decision THEORY,
so, heck, yeah.
The Big Bang Theory Season 11, Episode 10