Why, when an icon like Prince dies, does it feel like losing your best friend?
I don't know why we're so shocked when a famous person dies. We're all mortal, all subject to the same risks that are common to the human condition, whether we're well known, or not.
Yet, every time a celebrity dies, there's a stunned moment of dismay, before the tributes, obituaries and encomiums start flowing. It was exactly the same this week, when Prince passed away. Fifty-seven is young to die, for sure, but it's not unusual. So why the sense of sorrowful surprise?
It's true that there have been an awful lot of well-known deaths in 2016 - and we're still only in April. There's hysterical talk of 'The Great Celebrity Death Epidemic' and the illogical temptation is to look for some kind of pattern in it all.
It's akin to the notion of the 27 Club: the supposedly 'cursed' age at which numerous performers like Kurt Cobain, Jimi Hendrix, Janis Joplin and, more recently, Amy Winehouse suddenly died. We might think we live in an enlightened age, but primitive superstitions don't lurk so very far below the surface.
Similarly, in January, following the news of Terry Wogan's death, a media acquaintance said to me: "David Bowie, Alan Rickman and now Wogan - these things always seem to come in threes, don't they?"
I thought it a seriously bizarre remark at the time, as though he believed there was some kind of fatal cosmological plan that only applied to celebrities, who were destined to get picked off three at a time.
Even though that's pie-in-the-sky nonsense, it reflects a wider collective need to find some kind of significance in the passing of our stars. Coincidence, or random chance, doesn't satisfy that need for meaning.
Determined to get to the root of the matter, the BBC has been investigating.
It clocks a jump from only five celebrity obituaries used on its output between January and late-March 2012 to 24 in the same period this year, an almost five-fold increase. Why might that be?
According to obituary editor Nick Serpell: “People who started becoming famous in the 1960s are now entering their 70s and are starting to die. There are also more famous people than there used to be.
“In my father, or grandfather’s, generation, the only famous people really were from cinema — there was no television. Then, if anybody wasn’t on TV, they weren’t famous.”
That’s a very practical explanation, but I don’t think it comes close to accounting for our surprisingly strong reaction — sometimes almost amounting to disbelief, incredulity that this dreadful thing could have happened — to the passing of people who we have never met in our lives.
And it’s not a new thing. When Elvis Presley died in 1977, a surprising number of people refused to believe that the King had actually gone and there were numerous “sightings” of the risen Presley.
There’s often great affection for actors, broadcasters and comedians and a real sense of sadness when they pass. But I have a hunch that it’s the deaths of musicians that hurt us most.
Music has a particular way of weaving itself into our lives, and becoming part of our most transcendent experiences. Songs, and the people who write and sing them, can be a kind of emotional repository for our most powerful emotions. I remember listening to Prince’s strange, sexy song Raspberry Beret when I was 17, the age my daughter is now, and it seems forever part of that time of my life.
When I heard Prince had died, that song and its personal associations were immediately what I thought of. I didn’t know the man, of course. We never do know the person behind the glamorous performance: the ordinary human being that drinks coffee and goes shopping. Maybe we wouldn’t want to.
But there was an odd kind of intimacy there, because Prince’s music had become tangled up with my own powerful teenage sensations and left an indelible print. When he died, it was as though another small cord had been cut with my own past.
So, when we feel that sense of loss at the death of a star, perhaps we’re not really mourning for them. We’re mourning for ourselves.