A
circularity in the definition of being false
Consider the following claims:
To say “Snow is white is
true” is to say that snow is white.
To say “Ravens are black
is true” is to say that ravens are black.
To say “The Earth is round
is true” is to say that the Earth is round.
For someone who accepts these claims,
it is natural to think that we can define what it is to be false like so:
To say “snow is white is
false” is to say that it is not the case that snow is white.
To say “Ravens are black
is false” to say that it is not the case that ravens are black.
To say “The Earth is round
is false” is to say that it is not the case that the Earth is round.
And so on.
However, Saul Kripke
points out a problem with this definition. The problem is that the concept of
negation, of its not being the case, is defined by using a truth-table that
makes use of the concept of being false. So we get a circular definition: a
definition of what it is to be false in which the concept of being false is used
in the definition, because one of the components of that definition is in turn
defined using the concept of being false. Below is the truth table which
defines negation, with P standing for some proposition.
P |
Not P |
True |
False |
False |
True |
Circular definitions are not
acceptable. Kripke’s proposal is as follows: let us
be affimativists. In other words, let us suppose that
there are no falsehoods. When faced with something one might previously have
said is false, one should merely say, “I am very reluctant to endorse that
view.”
Reference
Kripke, S. 2015. Yet Another
Dogma of Empiricism. Philosophy and
Phenomenological Research 91: 381-385.