If you haven’t read the Harry Potter series, and in particular Harry Potter and the Half-Blood Prince, you may want to skip this entry. I want to write about a magic potion in that book which confers on its quaffer a power that, in my opinion, is one of the scariest and most unique powers in the series.

The potion I’m talking about is Felix Felicis, the luck potion. If you drink this potion it makes you lucky. Things go your way.

What’s so scary about that? Every time someone picks up a four-leaf clover or nails a horseshoe over their door they’re trying to do the same thing. Point is, those superstitions aren’t effective. If they were you would certainly notice it. When J. K. Rowling describes, in detail, what happens after Harry drinks a bottle of Felix Felicis, you realize what supernaturally good luck truly looks like. Thank goodness the potion only lasts for a day.

What is good luck, anyway?

Here you are, on the earth, a sentient being with a debatable amount of free will, sharing a pile of resources with a lot of other sentient beings. Sometimes they will want what you want, and there’s not enough to go around, particularly when it comes to things like time and money. When that happens, there are a variety of ways you can negotiate, on a spectrum that starts with barter and compromise, and goes all the way down through violence and war.

In this way most of Harry’s world is pretty familiar. Arthur C. Clarke once famously wrote that any sufficiently advanced technology is indistinguishable from magic. I’d say the corollary is that any sufficiently reliable magic is indistinguishable from technology. Questions of finite resources do not go away. For example, Harry and his fellow citizens have to use money, which ironically locates them lower on the magic/technology scale than the passengers of the Enterprise-D. There are other examples, too, like the fact of the Weasleys’ shabby robes or the way that house-elves have to make a banquet before it can magically appear.

The luck potion is similarly bound. For things to go well for you, they may need to go badly for your opponents. I loved Rowling’s description of what happens when Harry drinks it. It was convincing—and creepy. The potion sort of shouldered aside the Fates from their loom and fixed the threads to suit Harry’s ends. There’s no defense against it. Harry wants something from Professor Slughorn that Slughorn doesn’t want to give up. Harry gets it, which requires some bad luck for Slughorn. Harry’s love interest, Ginny, is interested in Dean Thomas, but the potion causes Ginny and Dean to have a falling out. Bad luck for Dean and maybe for Ginny. Think about what it means to be in Harry’s way or on his bad side when he’s full of the potion.

Even those around Harry who aren’t being directly thwarted are still basically being turned into pawns, even if they don’t lose a lot in the transaction. It’s like computer crime, where a criminal steals $10,000 by stealing one cent from each of a million people. Not that they’ll miss it, really, but it still feels wrong.

One reason Harry’s use of the potion doesn’t come across as sinister is because he is committed to the dangerous task of destroying Voldemort, something which will benefit nearly everyone, even Draco Malfoy. In this case, then, Harry’s good fortune is largely everyone’s good fortune.

Tolkien’s eucatastrophe is closer to this kind of luck. What’s interesting to me is that it seems both more familiar and more elusive. We want things to work together well for everyone, even while the evidence supports the theory that most of us are on the wrong end of an empty bottle of Felix Felicis.