Or were they? [Insert ominous organ music.]
Consider, instead, the possibility that Richards, a broken shell of a human being whose mere sweat drives drug-sniffing dogs into frothing frenzies, was not just joking when he admitted his morbid snorting habits, but was, in fact, absently admitting to the secret of his impossible existence. After all, this is a man most thought would not survive the '70s, '80s or '90s.
What if Richards, by snorting his father's ashes -- and who knows who else's? -- is using the souls of his ancestors to gain immortality in the face of non-stop substance abuse? It sounds absurd, but only because such notions of magical soul-eating have lost out to modernity. Countless ancient traditions hold that endocannibalism is a route to great power and even Highlander-like longevity. Endocannibalism (aside from being a fake-sounding word) refers to the consuming of flesh from the dead within one's own social group, almost always family members and/or ancestors -- you know, like a dead father named Bert.
One method involves grinding the deceased's remains -- often after they're first burned -- into a powder that is mixed with water and drunk. Snorting, while not a traditional method, works the same.
Why did certain groups embrace this tradition? Well, they believed that these meals allowed the, um, diners to gain the power of their dead relatives. Such cannibalistic practices are not exactly limited to "primitive people," either. The ancient Romans justified their persecution of early Christians with a passage from the Book of John that was easily misinterpreted thanks to its creepy factor:
"Those who eat my flesh and drink my blood have eternal life..." (John 6:54)
In other words, Christians partake in exocannibalism, in which they consume the flesh of those outside their familial group to gain their power -- you know, like eternal salvation.
Long story short: Eating the dead is good for the life span -- which is why it's entirely possible that Richards has been snorting his father (and again, who knows who else?) to steal a bit of his soul, his power, his magic or whatever you want to call it. Considering the debauchery and biological mutilation the guitarist has inflicted upon himself over his life, all of which is reflected in his craggy, droopy exterior (which makes him look like a zombie-flick extra), this seems to be the best explanation of how he's survived it all.
Keith Richards is a cannibal.