Because of a recent question I ended up reading through the Painkill-discussion on meta and in the linked question the_OTHER_DJMethaneMan wrote in a comment
Is there a way to "rate" the "level" of pain? None that I am aware of.
Question: Is it possible or likely possible to measure pain scientifically (including assigning some numbers/unit with the same seriousness as length, time, etc.) and build machines doing that with today's technology?
My starting point: Wikipedia writes "Pain is a distressing feeling often caused by intense or damaging stimuli." It lists different types of pain: "Nociceptive" (pain is "detected" by sensor cells), "Neuropathic" (pain as damage to the nervous system) and "Psychogenic" (basically emotional pain).
Wikipedia further writes "A person's self-report is the most reliable measure of pain." and quotes Margo McCaffery: "Pain is whatever the experiencing person says it is, existing whenever he says it does". It also has a long list of pain scales which are in most cases not further explained. Wikipedia also provided scales for humans that can not communicate pain, e.g. this one.
However, I don't want patients telling their pain, but measuring it independently. I image something like this could be archived with brain activity per second or something like that, if there is a pain part in the brain. Wikipedia briefly reports on that too in this section. However, the linked FMRI page doesn't contain the word "pain" and the 3 references in the section I just linked are all from 2011 and I'm not a physician, so I dare not to judge if they are affirmative to my question or just wishful thinking. I also don't know if these can measure all three parts of the pain or not. If someone with a medical background could give some evaluation on that point, this would be great. Other insightful answers to the question above are appreciated, too, of course.
Background, if you need one: While I think my question above (without looking at my own research and ideas stated thereafter) is specific and general enough to be on-topic here, I'll give some background that brought me to the question in case someone is interested. I insist that this is additional information not needed for answering the question, but some may find it interesting nevertheless. Feel free to edit this part out if it isn't in the spirit of the community.
In my story there is a magic that is defined to inflict the utmost pain possible on individuals, and it is of course regarded evil and forbidden. Then there is this villain (basically evil incarnate) who, as part of that universe, cannot now that this magic is per definition the worst, so he tries to beat it with other means. Cruelty ensues, but the maniac takes a scientific approach and tries to measure just how bad he can be. When the heroes finally stop the villain on his never-ending conquest, just looking at the tip of the iceberg of what he has done disgusts them so much they destroy everything without a second look. The end. (Or is it?)
Sidenote: Of course I can do the measurement magically, but it seems more evil to me if the maniac actually uses scientific methods.
EDIT: I decided to move further on-topic discussions to chat.