Well, now you mention it Hive account@pandorasbox ... The ground-principle of philosopher Descartes' work is exactly that what you just wrote here...
He dedicated most of his life thinking about what were some 'fundamental truths'; looking for life's foundations that were unquestionable, timeless, ... Essentially he was actually searching for what were the rudiment principles on which reality is built.
Not our reality, but THE reality.
(To be fair, most philosophers from that time ended up with theories saying there were multiple dimensions, and that the human perception of what reality was was actually completely false... #mushroomsmuch? ;) )

Anyhow, Descarted ended up with only one truth he could be sure of:

Je pense, donc je suis

("I think, so I must exist")

...

Aside from that, he says you can't be sure of anything...

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