What is the difference between "neither true nor false" and "either true or false."?

I was reading about definitions

And I read a line saying "Lexical definitions are either true or false".

After sometime, I read a line saying "Stipulative definitions are neither true nor false".

Hence I got confused and hence the question. To me they sound the same.

An example would help. Thank You.

  • 1
    This seems more like a question about the meaning of "either" and "neither".
    – E...
    Commented Sep 29, 2019 at 21:37
  • They are using "true" and "false" in a rather peculiar way. What they mean is that lexical definitions are descriptive of the actual usage, and can describe it correctly or incorrectly ("either true or false"), while stipulative definitions are prescriptive, they stipulate what the meaning should be. As such, there is nothing they can be correct or incorrect about ("neither true nor false"), although they can still be practically useful or not.
    – Conifold
    Commented Sep 29, 2019 at 21:47
  • Suppose a lexical definition is true, what do we mean by that? Does the truth value of a lexical definition differ from one person to another?
    – shillong
    Commented Sep 30, 2019 at 4:40
  • Can't we regard a stipulative defn to be always true if used within the context? Sorry that I'm asking different questions, I want to be very clear with the truth value of definitions.
    – shillong
    Commented Sep 30, 2019 at 4:42
  • "True" is a wrong word to use here, but the "truth value" of a lexical definition does not vary across people because it is anchored to the average use, just as average temperature does not vary from place to place, although the actual temperature it is based on does. We are not free to "regard" something as "true", and there is little point to it. "Truth", or rather adequacy, is supposed to stand for correspondence to something independently existent, there us nothing like that for stipulative definitions. But they can be good or bad for this or that purpose.
    – Conifold
    Commented Oct 1, 2019 at 17:49

1 Answer 1


"Neither true nor false”

means that the statement has no definite truth valued : it lives in a sort of limbo, a truth value-gap between true and false.

“Either true or false”

means that the statement has (exactly) one of the two truth values.

To say that "Lexical definitions are either true or false" means that a Lexical definition :

also known as dictionary definition, is the meaning of the term in common usage. [..] Note that a lexical definition is descriptive.

Thus, it states a fact : that the defined term has a certain meaning, and it cab be right (true) or wrong (flase).

A Stipulative definition instead, is a sort of convention :

in which a new [...] term is given a new specific meaning for the purposes of argument or discussion in a given context.

Thus, it has no sense to ask if it is true or false.

Compare OR with NOR.

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