Earlier quoted context omitted.
He left two words off: "That I am having a subjective experience is undeniable [to myself]." You cannot prove, even to yourself, that you are not a brain in a vat. All you can prove is that you are experiencing something. And what little that is cannot even be proven to anybody else - no matter what you do. Consciousness is quite a personal affair.
Neuralink is going to be so interesting if it can allow two brains to communicate more directly than words.
But what Neuralink wants to do eventually is "enhance" your brain with computers hooked up to Ai.
Do you have ANY idea how quickly your brain would burn through physical precursors to the thinking process while trying to handle all that?
I mean, "in theory" if a computer would do something like solve a complex equation and give you the answer right away while you were trying to do something like, say, pay your taxes – fine.
But how would that be controlled? What if the computer wanted to "share a whole bunch of interesting stuff it's processing" ... how would that be controlled and how would your brain be protected from that so it doesn't burn out trying to keep up with everything?