"logically necessary" is correct and usable in written English.
You can use it when you want to refer to a piece of reasoning that is logically required, or when something is required in order to come to a logical conclusion. For example: "Based on our current understanding of the situation, it is logically necessary that we take action immediately."
A proposition is logically necessary if it instantiates a law of logic or can be made to instantiate a law of logic through substitution of definitionally equivalent terms.
In this logic, the language permits the expression of two different notions of necessity: the logical necessity, symbolized by □, and the physical necessity, symbolized by ⊡. meaning that logical necessity is stronger than physical necessity: anything that is logically necessary is physically necessary.
Logically necessary existence, it is said, is an incoherent idea, for logical necessity applies to the relations between concepts, not to their instantiation.
This point is logically necessary.
Is it because they see it as logically necessary?
But laws of nature are not logically necessary (that is, denying them is not a contradiction).
Strachey was a great persuader; The Coming Struggle for Power, published in 1932, made communism seem practical and logically necessary.
As Greg puts it, "It is not clear that the laws of nature are not logically necessary.
It is as important and logically necessary to acknowledge the possibility of wrongful accusations of sexual assault as it is to recognize that most rape claims are true.
Since different things were each the all, the self, and divine, it became logically necessary to postulate an unmanifest source or cause of the Yogic experience of absorption.
It should be noted that this is not merely a logically necessary property of equality but an assumption about the membership relation as well.
