The phrase "theory in which" is grammatically correct and commonly used in written English.
It is typically used to introduce a subordinate clause that explains the main subject or action of the sentence. Here is an example: "The theory in which gravity is caused by the curvature of space-time has been widely accepted in the scientific community."
For this reason Heisenberg supplemented this picture with a theory in which measurement figures prominently.
The Black-Scholes equation was based on arbitrage pricing theory, in which both drift and volatility are constant.
There is the liberal theory, in which teams of experts draw up plans to engineer order wherever problems arise.
"It confirms one theory in which you have these objects come together to form a nucleus," he said.
As one example, Lee Smolin, a physicist at the Perimeter Institute for Theoretical Physics, has invented a theory in which the laws of nature change with time.
She launches into a long, swerving monologue about something called Ignatian Theory, in which an Irish priest called Father Billy has apparently been instructing her.
They must first pass an oral test of wine theory, in which examinees are expected to show encyclopedic knowledge of wine-growing regions and styles.
But the greater pursuit is for a kind of unified field theory in which psychology and physiology — the subjective and the material realms — would finally be integrated.
He had begun to consider a new theory, in which hyperactivity originated in the central nervous system rather than in the inner ear.
Although Dembski is somewhat noncommittal, he seems to favor a design theory in which an intelligent agent programmed design into early life, or even into the early universe.
Some in London were developing a fearful Middle Eastern domino theory, in which they envisaged the Strait of Hormuz falling under communist control.
