identity

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Related to numerical identity: Qualitative identity

identity

a means of portraying arithmetically the enduring equality between two (or more) VARIABLES that are equal by definition. For example, £1 = 100p (or $1 = 100¢), and no matter how many pounds (or dollars) we have, they can always be converted into pennies (or cents) by multiplying by 100. Identities are generally given a three-bar ‘identity’ sign (=) to indicate that the value to the left of the three bars is identical to the value to the right of the sign. The QUANTITY THEORY OF MONEY is one of the best-known examples of an identity in economics, written as:

where M is the money stock, V is the velocity of circulation of money, P is the general price level and T is the number of transactions undertaken. See EQUATION.

References in periodicals archive ?
Consider numerical identity. To say that the self is numerically identical with itself is to say that it is always self-same, never some other, always having the exact same properties and never losing any of those properties.
The first of these arguments passes too easily over difficult questions of personal and numerical identity. It is by no means obvious that merely because one thing can become two separate things that it thereby has less or no value.
1) a numerical sense (numerical identity), when a thing has many names, yet it is only one thing (for instance, "coat" and "mantle");
He calls them "perfect" and "imperfect" identity and we could assimilate them to numerical identity and specific (ordinary) identity (3), respectively.
He renames the persistence problem the problem of "numerical identity" in order to differentiate his position from those of psychology-based theorists, which concentrate instead on singularity of mind, requiring that an individual's psychological states be continuous--or at least connected--for her to be the same person over a period of time.

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