Dictionary Definition
validity
Noun
2 the quality of having legal force or
effectiveness [syn: validness]
User Contributed Dictionary
English
Noun
 The state of being valid, authentic or genuine.
 Having legal force.
 A quality of a measurement indicating the degree to which the measure reflects the underlying construct, that is, whether it measures what it purports to measure (see reliability).
Translations
the state of being valid, authentic or genuine
 Finnish: kelpoisuus, validiteetti
 Greek: εγκυρότητα (egkirótita)
having legal force
 Finnish: sitovuus, laillisuus
a quality of a measurement indicating the degree
to which the measure reflects the underlying construct
 Finnish: oikeellisuus
Extensive Definition
The term validity (also called logical truth,
analytic truth, or necessary truth) as it occurs in logic refers generally to a
property of particular statements and deductive arguments. Although
validity and logical truth are synonymous concepts, the terms are
used variously in different contexts. Whether or not logical truth
is analytic truth is a matter of clarification.
Logical truth of statements
What is and is not considered a logical truth has
been a matter for clarification, even up to the early part of the
20th Century.
A logical truth was considered by Ludwig
Wittgenstein to be a statement which is true in all possible
worlds. This is contrasted with synthetic claim (or fact) which is only true in this
world as it has historically unfolded.
Later, with the rise of formal logic a logical
truth was considered to be a statement which is true under all
possible interpretations.
Logical truths are necessarily true. A proposition such as “If p
and q, then p.” and the proposition “All husbands are married.” are
considered to be logical truths because they are true because of
their meanings and not
because of any facts of the world. They are such that they could
not be untrue.
Logic is concerned
with the patterns in reason that can help tell us if a
proposition is true
or not. However, logic does not deal with truth in the absolute
sense, as for instance a metaphysician does.
Logicians use formal
languages to express the truths which they are concerned with,
and as such there is only truth under some interpretation or truth
within some logical
system.
Validity of arguments
When an argument is set forth to prove that its
conclusion is true (as opposed to probably true), then the argument
is intended to be deductive. An argument set
forth to show that its conclusion is probably true may be regarded
as inductive.
To say that an argument is valid is to say that the conclusion
really does follow from the premises. That is, an argument is valid
precisely when it cannot possibly lead from true premises to a
false conclusion. The following definition is fairly typical:

 An argument is deductively valid if, whenever all premises are true, the conclusion is also necessarily true.
An argument that is not valid is said to be
‘’invalid’’.
An example of a valid argument is given by the
following wellknown syllogism:
 All men are mortal.
 Socrates is a man.
 Therefore, Socrates is mortal.
What makes this a valid argument is not the mere
fact that it has true premises and a true conclusion, but the fact
of the logical necessity of the conclusion, given the two premises.
No matter how the universe might be constructed, it could never be
the case that this argument should turn out to have simultaneously
true premises but a false conclusion. The above argument may be
contrasted with the following invalid one:
 All men are mortal.
 Socrates is mortal.
 Therefore, Socrates is a man.
In this case, the conclusion does not follow
inescapably from the premise: a universe is easily imagined in
which ‘Socrates’ is not a man but a woman, so that in fact the
above premises would be true but the conclusion false. This
possibility makes the argument invalid. (Although whether or not an
argument is valid does not depend on what anyone could actually
imagine to be the case, this approach helps us evaluate some
arguments.)
A standard view is that whether an argument is
valid is a matter of the argument’s logical
form. Many techniques are employed by logicians to represent an
argument’s logical form. A simple example, applied to the above two
illustrations, is the following: Let the letters ‘P’, ‘Q’, and ‘s’
stand, respectively, for the set of men, the set of mortals, and
Socrates. Using these symbols, the first argument may be
abbreviated as:
 All P are Q.
 s is a P.
 Therefore, s is a Q.
Similarly, the second argument becomes:
 All P are Q.
 s is a Q.
 Therefore, s is a P.
These abbreviations make plain the logical form
of each respective argument. At this level, notice that we can talk
about any arguments that may take on one or the other of the above
two configurations, by replacing the letters P, Q and s by
appropriate expressions. Of particular interest is the fact that we
may exploit an argument's form to help discover whether or not the
argument from which it has been obtained is or is not valid. To do
this, we define an “interpretation”
of the argument as an assignment of sets of objects to the
uppercase letters in the argument form, and the assignment of a
single individual member of a set to the lowercase letters of the
argument form. Thus, letting P stand for the set of men, Q stand
for the set of mortals, and s stand for Socrates is an
interpretation of each of the above arguments. Using this
terminology, we may give a formal analogue of the definition of
deductive validity:
 An argument is formally valid if its form is one such that for each interpretation under which the premises are all true also the conclusion is true.
As already seen, the interpretation given above
does cause the second argument form to have true premises and false
conclusion, hence demonstrating its invalidity.
Validity of statements
A statement can be called valid if it is true in all interpretations. For example: If no god is mortal, then no mortal is a god.
In logical form, this is:
 If (No P is a Q), then (No Q is a P).
A given statement can also be valid relative to
(the truth of) other statements. This means that an argument with
the given statement as its conclusion and the other statements as
its premises is a valid argument.
validity in German: Allgemeingültigkeit
validity in Estonian: Kehtivus
validity in French: Valide
validity in Hebrew: תקפות (לוגיקה)
validity in Japanese: 妥当性
validity in Lithuanian: Validumas
validity in Macedonian: Валидност
validity in Dutch: Geldigheid en
gezondheid
validity in Portuguese: Validade
validity in Serbian: Валидност
validity in Swedish: Universalitet
validity in Ukrainian: Чинність
validity in Chinese: 有效性
Synonyms, Antonyms and Related Words
actionability, admissibility, admissibleness, advantageousness,
agreeableness,
allowableness,
amperage, applicability, armipotence, auspiciousness, authenticity, authoritativeness,
authority, beef, beneficialness, benevolence, benignity, black power, brute
force, calculability, charge, charisma, class, clout, cogence, cogency, compulsion, constitutional
validity, constitutionalism,
constitutionality,
dependability,
desert, dint, drive, due process, duress, effect, effectiveness, effectuality, efficacy, energy, excellence, expedience, fairness, faithworthiness,
favorableness,
fineness, firmness, firstrateness,
flower power, force, force
majeure, forcefulness, full blast,
full force, goodliness, goodness, grace, gravity, healthiness, helpfulness, influence, invincibility, jurisdiction, justice, justiciability, justifiableness,
justness, kindness, lawfulness, legal form, legal
process, legalism,
legality, legitimacy, legitimateness, licitness, main force, main
strength, mana, merit, might, might and main, mightiness, moxie, muscle power, niceness, permissibility, permissibleness,
pizzazz, pleasantness, poop, potence, potency, potentiality, power, power pack, power
structure, power struggle, powerfulness, predictability, prepotency, productiveness, productivity, profitableness, puissance, pull, punch, push, quality, reliability, rewardingness, rightfulness, sanctionableness,
scope, secureness, security, sinew, skillfulness, solidity, soundness, stability, staunchness, steadfastness, steadiness, steam, strength, strong arm, substantiality, superiority, superpower, trustworthiness,
unerringness,
usefulness, value, vehemence, vigor, vim, virility, virtue, virtuousness, virulence, vitality, warrantableness,
wattage, weight, wholeness, worth