A data point from my personal experience: 15 years ago I started developing acute dysphagia (difficulty swallowing) which eventually got so severe I went to see a doctor about it. It was diagnosed as acid reflux, and I was prescribed proton pump inhibitors. That seemed to help for a long time, but a few years ago the symptoms started to return. They got so bad that I went back to the doctor, and this time was diagnosed with a newly discovered malady called eosinophilic esophagitis (EOE -- http://www.aaaai.org/conditions-and-treatments/related-condi...). EOE is an allergic reaction in the esophagus, which made sense because the initial symptoms appeared shortly after we got pets -- a dog and a cat -- for the first time, and I'm allergic to both. Case closed, or so I thought.

A few months ago, despite the fact that both or dog and cat had long since died, my symptoms started to come back worse than ever. Things got so bad that at one point I was actually heading to the emergency room (I never made it because before we got there I threw up, which fixed the immediate problem). But that episode scared me enough that I made another doctors appointment.

There followed a truly bizarre confluence of circumstances: first, my wife fell down and broke her arm. Then my doctors office called to confirm my appointment, but my wife picked up the phone and thought it was her doctors office calling about her arm. She thought the appointment was for her, but she hadn't made an appointment, so she told them the appointment was a mistake an they should cancel it, which they did. I called to reschedule, and that delayed it for another few weeks. The day of my new appointment, my doctors office called and said they were running hours behind because of computer problems and needed to reschedule again. Bottom line: it has been several months now and I still haven't been able to see a doctor.

But here's the punch line: in the intervening time, my symptoms have completely disappeared. If I had been able to see a doctor, I would almost certainly have ascribed this positive outcome to any intervention she would have done. And yet there has been no intervention, but only because of these weird twists of fate that kept me from seeing my doctor. Moreover, I know there has been no intervention. And yet I suddenly feel better than I have in 15 years. It's really weird.