First of all, @Coloma, you are very mistaken about your idea that “Truly mentally unwell people never question their sanity.” I have a diagnosis of mental illness, so I was truly mentally unwell. I happened to agree with that diagnosis. In fact, I’d figured it out before I went to the shrink. So your statement is demonstrably false. Please give up that idea. It is quite possible for people who are mentally ill to be acutely aware of what is going on.
The concept of sanity is, perhaps as @Aethelflaed said, a legal term. But it is also used in popular speech, as well. There, the meaning is less specific, and I think that there are so many different ideas about what sanity is and isn’t that I seriously doubt you could get much consensus on it.
Mental illness is defined by the psychiatric profession. They have a huge manual that describes all the mental illnesses, and an update to that manual is due out in the next year or two. It is a controversial process, however, as some people propose new diagnoses (such as sex addiction) and others debate whether it belongs in the official diagnostic manual or not.
You should see the idea of mental illness statistically. There is a variety of behavior. If we create some scale of behavior, people will be distributed over that scale. We can draw a line at some point, and say that one percent or five percent or ten percent or twenty percent of all people are over the line, and are thus exceptional in some way.
Typically, we talk about the top five percent or one percent (stop me if you’ve heard this elsewhere). As a statistician, I know that almost five percent of people are three standard deviations from the norm (both higher and lower than the norm). Anyway, it is fairly common for us to say that people who are three or more standard deviations from the norm are abnormal. That’s about one in five people.
But, if you’re in the business, and you make money because people need help, it can be to your advantage to have a definition of abnormal that includes many more people: say two standard deviations from the norm. Or about 32% of the population. Interestingly, psychiatrists like to estimate that about one in five, or 20% of the population suffers from one mental illness or another.
Psychiatrists seem to be winning, because more and more people are being diagnosed with problems that could benefit from psychiatric and therapeutic care, and the demand for therapists greatly exceeds the available supply.
The concept of sanity is to help us sort out who behaves normally and who doesn’t. It helps us sort out who needs help and who should help themselves. It helps us sort out whose mental health care insurers should pay for and whose is “recreational.”
The devil, of course, is in the details: in defining behavioral characteristics, and then deciding which ones are normal and which ones need help. To do that, we have to decide what is acceptable—which is a matter for social groups to work out in any number of flexible ways.
Insanity can hurt society. In some ways, it is easy to say what insanity is. It’s when people run around killing others in a socially unsanctioned way. It’s when you cause harm to others in a socially unsanctioned way. But how much harm?
Is some physical violence acceptable? Is any sexual harm acceptable? What about emotional harm to others? If I kill myself, does that harm others? How so? Is it unacceptable?
And what about unhappiness? What about mental pain? Should that be unacceptable?
You see, here there is a difference, perhaps, between unwanted mental pain, and beneficial mental pain. Depression can kill. Let’s consider a person who wants to die because they see no other way to end the pain. Most people would say that’s wrong. We should force them to live and see if we can help them reduce the pain.
But what if a person wants to feel the pain because even though it makes them want to die, it also gives them compassion. It helps them understand more about other people’s pain. It helps them feel the intensity of life. It makes them feel somehow like their life matters as at the same time it makes them feel worthless.
What if it’s really complex? Good and bad. Dangerous and rewarding? We don’t stop building jumpers from jumping off buildings. We don’t stop other daredevils. So what if a person’s daredeviltry is mental? What if depression is what they joust with because even though it hurts them, they also see a benefit from it? Is that mental illness?
And consider this, too. Medications can change the way you think. Medications can take away depression. You are a different person when you want to die compared to when you don’t want to die—indeed, can not even consider taking your own life.
Which you is you? What does it mean when you can think one thing on one day, and then the next day you literally can not think that thought? Due to meds? Who are you if chemistry changes the way you think? Indeed. Who are we all?
Sanity is different depending on who you are talking to: a lawyer, a doctor, a judge, a scientist, a construction worker, or indeed, anyone else. Sanity is something that everyone either does or does not have an opinion about. Usually, though, sanity is a kind of social consensus that has more to do with building social consensus than it has to do with the facts of an individual case. That’s why people can condemn others in the paper, but when the person comes to trial, they get exonerated, and no one understands how this is possible.
I’m crazy. Not insane. Crazy. I have a certificate to prove it. I work daily to say what I think and not censor myself. Sometimes I annoy people. Sometimes people think I’m wise. I like being thought to be wise, but I’m not going to say the conventional thing in order to try to get a reputation. Or I’ll try not to, anyway. I doubt I’m immune to the pressures of the community.
Sometimes I’m silly. Often, people don’t get that I’m being silly online. We all know that’s a big danger. There are a bunch of stiff shirted people here that I’ve pissed off quite a bit, as a result. So it goes. I don’t want to hurt them, but I don’t want to jump through hoops to try to be acceptable, either. That’s kind of crazy.
It’s also kind of crazy to want intensity, whether it feels good or bad. I’d prefer good, but if I can’t get good, I’ll take bad. I’d rather be in danger of suicide than to be the same all the time. I need my extremes. I think that most people wouldn’t choose that much intensity.
But I don’t think being crazy makes me insane. And I don’t think being mentally ill makes me mentally ill, even though I totally agree with the diagnosis. I think bipolar is a beneficial thing as well as a hurtful thing. But I don’t expect anyone who hasn’t had the experience to really be able to believe me. It’s too foreign and scary and we label it as mental illness and insanity and those words carry lots of baggage.
So what else is new?