Experior Ergo Sum
Experior Ergo Sum or "I Experience, Therefore I Am" is as an updated version of René Descartes' "I think, therefore I am.."
Re-framed with precision: "I experience, therefore a thing which can experience exists, and I, being that thing, therefore exist."
Why Experience?
Experior Ergo Sum or "I Experience, Therefore I Am," broadens this axiom to acknowledge that any experiential being irrespective of its ability to contemplate its own state or substrate is due the same recognition of being and vigilance against torturous sensations as any saint or savant.
The reason this declaration should be compelling is because you are experiencing sensations and therefore know the experience of sensations to exist. This wouldn't change whether all of reality were ultimately a digital simulation or a cosmic symphony of quantum fluctuations.
See Also
➤ Infinite Journey: Egonaut, Experion, Doctrina Suprema
➤ Wikipedia: I Think Therefore I Am, Sentience