Translating Negations
We place the tilde in front of a wff, so the most obvious translation involving the
tilde is one where the English phrase is "it is not the case that", as in:
Translation: |
Commentary: |
It is not the case that France is in South America. |
English sentence to be translated |
A: France is in South America |
Sentence letter abbreviation for simple sentence |
It is not the case that A |
Replacement of simple sentence by sentence letter |
~A |
Full translation |
Negations don't always occur at the beginning of a sentence, however, and this very
sentence is a great example!
Translation: |
Commentary: |
Negations don't always occur at the beginning of a sentence, however, and
this very sentence is a great example! |
English sentence to be translated |
A: Negations always occur at the beginning of a sentence B: This very
sentence is a great example. |
Sentence letter abbreviations for simple sentence |
It is not the case that A, and B |
Replacement of simple sentence by sentence letter |
(~A & B) |
Full translation |
In this sentence, the negation is buried in "don't. So we move it
outside in the second step to make it explicit. But in doing so, we have to take care to
in respect the proper scope of the negation sign. By that we mean that we're only
negating the left half of the conjunction, not the whole conjunction.
When negations have a wider scope than a
single sentence letter or its negation, that is usually signalled by the use of
a grouping indicator in English. For conjunctions, look for the grouping
indicator "both." For disjunctions, look for the grouping indicator "either."
Here is an example of the use of negation and "either" to produce the negation
of a disjunction:
Translation: |
Commentary: |
It is not the case that either war is
justified or aggression warranted. |
English sentence to be translated |
A: War is justified. B:
Aggression is warranted. |
Sentence letter abbreviations for simple sentence |
It is not the case that either A
or B |
Replacement of simple sentence by sentence letter |
~(A v B) |
Full translation |
|