"I'm not convinced humans can't."
You're not convinced? Wow. There's a new powder that can apparently regenerate portions of the body (a fingertip at the least) but we don't naturally have the ability. Obviously. Or at least it's obvious to everyone but you.
"Heck, we regenerate things all the time: muscle, skin, brain, bone, even spinal columns to some degree, etc."
Within reason.
"Granted we are not as capable of regeneration as we might like to be, but maybe we just haven't yet learned how to do it."
I certainly hope you mean we haven't developed any techniques to do it rather than what I think you mean by "learned how." Of course it is Supersport so...
"Maybe regeneration takes belief, for example."
No. It takes substantial medical, biological, biochemical and genetic information. You know, all that eeeevil sciency stuff you despise.
"But if a doctor tells a paraplegic that he'll never walk again, why in the world would he ever believe otherwise?"
Look at the mega churches on television and you'll see all kinds of people who believe some schmuck with a bad suit and worse haircut will make them walk again.
"It's the same with cancer. We all know the placebo effect is real, yet doctors insist on giving cancer patients death sentences by saying things like "I'm sorry but you've only got 6 months to live.""
They say that because statistically that's what they've got. What do you want them to say, "sorry, but you've got terminal cancer and will probably only live another 70 years or so"?
"Well gee wiz, doc....thanks for giving people absolutely no hope."
Such "hope" is for the feeble minded such as yourself who would believe such with no reason to.
"It may or may not be the same with regeneration in humans. Of course the scientific community would never test such a thing."
Describe how such a thing would be tested using your ideas.