The phrase "a given theory" is correct and usable in written English.
It can be used when referring to a specific theory that has been previously mentioned or is understood in the context.
Example: "In the context of our discussion, we will analyze the implications of a given theory on social behavior."
Alternatives: "a specific theory" or "an established theory".
How do archaeologists keep themselves from seeing only the facts that fit a given theory?
Indeed, the fact that no amount of evidence can decisively show that a given theory is true (as opposed to merely predictively successful) begs the question of whether it is meaningful to say that a theory is "true" or "false".
Although the shape and structure of those systems cannot be discussed in any detail here, it should nonetheless be noted that a robust understanding of each of the major theories and texts in the history of philosophy of law requires some acquaintance with the legal systems of the cities and states in which a given theory was developed.
Different models of a given theory will share some dimensions of their state space while differing in others.
On such views, the bearing of a given body of evidence on a given theory becomes a highly relativized matter.
Even when such disputes can be settled, there remains plenty of room for arguing over whether a given theory does indeed adequately explain the phenomenon.
Derrida's deconstructive readings often unearth binary oppositions that are projected as an unstable center of any given theory and thereby should make us deeply skeptical of any given method.
Geach's threat of circularity can be avoided if an independently given theory of how attention is constituted can be shown to illuminate the way in which reference is fixed by it.
And as Wren-Lewis points out, this was in a way a case of giving theory priority over evidence.
What we are after is supertasks formulated within the defined framework of a given physical theory which can tell us something exciting and/or new about that theory.
The fact that default theories can have zero, one, or multiple extensions raises the issue of what inferences one is warranted in drawing from a given default theory.
