Can the following be true or is it a contradiction?
$ \exists x P(x) \wedge \exists x \neg P(x) $
Sorry if this is an obvious question, i'm new to this topic.
Can the following be true or is it a contradiction?
$ \exists x P(x) \wedge \exists x \neg P(x) $
Sorry if this is an obvious question, i'm new to this topic.
The important point is that the two $x$s are different. They are each dummy variables that extend from the $\exists$ to the $P(x)$. A far better way to write the sentence is $$\exists x P(x) \wedge \exists y \neg P(y)$$ This is logically equivalent to your expression, but it avoids the confusion caused by reusing variables. In this version, it is easy to see that the sentence can be true,