Wouldn't the fact that it's common knowledge preclude it from being asked? That would make it a pointless question, which is almost identical to a stupid one.
Why do so many people come here for suicide advice? There are various credible sources that provide the best suicide methods online.
Well, what is pain? A neurological signal, right? The brain itself is devoid of pain receptors, which I'm sure you know... People can get brain surgery and remain conscious, which they have to be sometimes for certain procedures. Paralysis of various sorts also demonstrate a lack of pain signals from paralyzed areas. (Of course, certain kinds of paralysis do this and others don't. Also, amputees do report weird phenomena called "phantom limb pain.") In any case, they could medically verify that that kind of pain wouldn't reach anywhere that could detect it with some kinds of brain scan, etc.
This is the medical, objective and empirical view of pain. Anything esoteric or subjective is up for more debate.
Buttered Toast stated: source post
People can get brain surgery and remain conscious, which they have to be sometimes for certain procedures.
Does one's last meal count as a procedure?