A little knowledge, so the saying is generally quoted, is a dangerous thing.
Not in and of itself, it isn't. What the aphorism means is that the danger lies in how one utilizes the knowledge, and generally-speaking, I think it means that if you think you know more than you do, that can trip you up.
Ignorance can be bliss, but it can kill you. What kind of snake is that? Who knows? Pick it up, it looks harmless enough ...
Red-touch-yellow, kill a fellow. Better let it alone.
Knowing just enough to get yourself into trouble probably won't happen if you don't try to overstep what you have.
And a little knowledge tends to make you appreciate much more somebody who has a lot of it.
When I worked the phones at the clinic years ago, I'd get calls from folks who didn't want to come in and who wanted to be diagnosed and treated over the phone. I was an LPN and worked my way into being a Physician's Assistant with a national certification and a license to practice in a couple of states and all, but unseen diagnosis based on symptoms without signs is a mug's game. I was fairly good at it, but I didn't take any big risks.
Most of the time, most illnesses are benign, and most of the time, will resolve on their own.
Which probably saves a lot of medics from malpractice suits.
Sure, some illnesses are fairly evident, and the old saw about hearing hoofbeats and not looking for zebras applies, (unless you are in Africa), but still, there are only so many ways that illnesses manifest, and sorting them out can be tricky.
If you call during flu seasons and rattle off a list that sounds like it's the flu? Coughing, sneezing, aches, fever, like that, then chances are you have the flu.
But there are other things it might be, and I can ask questions and work toward a differential diagnosis over the phone–are you coughing up phlegm? What color is it? How high is your fever? Does your neck feel stiff and sore? –whose answers will likely shift what you have into another category. You have high fever and a stiff neck? Come on in, now. Might be encephalitis or meningitis–riding that out at home could do you in.
If I told you all the things that it could be, based on common symptoms alone, we could be there a long time.
Say, Doc, I got this tingling and a little numbness in my finger tips. What could that be?
Well, I'm not the doctor, only his assistant, but, well, it could be carpal tunnel, maybe a vibrational-injury, or a pinched nerve in your neck.
Or a stroke.
Or leprosy ...
If you know a little bit and you offer it at the wrong time, it might not be so good. Then again, being able to dislodge something stuck in somebody's windpipe, or to stop major bleeding isn't much the way of medical knowledge, but in the right situation, it is worth diamonds and then some.
Knowledge is power–used in the right way at the right time.