[OldNavyVet]

“I stand by my original statement”

i.e. “Nothing is certain.”

Are you sure you exist?

[who_would_fardels_bear]

"Are you sure you exist?"

Rene Descartes walks into a bar.
Then a horse walks into the bar.
The bartender says "I thought da' horse came before Descartes?"

Rene Descartes sits down at the bar.
The bartender asks him "Will you be having a drink?"
Rene Descartes says "I think not" ...

...and disappears.

[lmr]

“I stand by my original statement”

i.e. “Nothing is certain.”

Are you sure you exist?

What is the purpose of this question? It seems to be nothing more than a Red Herring.

[lmr]

You have also taken 2 unrelated phrases of mine and put them together to make some kind of point, it seems.

You need more practice at twisting what people are saying. You are trying, but not succeeding.