\begin{definition}[Definition:Contradiction]
A '''contradiction''' is a statement which is ''always false'', independently of any relevant circumstances that could theoretically influence its truth value.
This has the form:
:$p \land \neg p$
or, equivalently:
:$\neg p \land p$
that is:
:'''$p$ is true and, at the same time, $p$ is not true.'''
An example of a "relevant circumstance" here is the truth value of $p$.
The archetypal '''contradiction''' can be symbolised by $\bot$, and referred to as bottom.
\end{definition}