Concept:
Wittgenstein discussed certainty and skepticism in his later philosophy, especially in On Certainty.
He argued that doubt itself requires a background of certainty.
Step 1: Understand skepticism.
Skepticism means doubt about knowledge claims.
But meaningful doubt cannot be unlimited.
If everything is doubted, then even the meaning of doubt becomes unclear.
Step 2: Understand ground of certainty.
Wittgenstein says that some basic certainties work like hinges.
They are not normally doubted because they make ordinary questioning and doubting possible.
Step 3: Connect with Wittgenstein.
The idea that meaningful skepticism presupposes certainty is strongly associated with:
\[
\text{Ludwig Wittgenstein}
\]
Hence:
\[
\boxed{\text{Ludwig Wittgenstein}}
\]