Here’s a fun little thought-experiment, derived from the work of Ernest Gellner. Try jotting down a list of all the things you love about your partner, if you have one. (If you don’t, try to picture your perfect beloved. If you’re just not into romantic love at all, sit back and enjoy what we’re about to do to the concept.)

Don’t panic if you find making this list harder than you think it should be. How do you sum up somebody you love in just a few adjectives? It almost feels like a sort of betrayal to even try, treating someone as if they could be reduced to a laundry-list of lovable qualities. Faced with the task, some people will fall back on cliché or generic praise (“He’s so kind and has a great sense of humour”) while others may reach for detail so concrete nobody else could appreciate it (“I love the way the corner of her eyes scrunch up when she groans at my jokes.”).

Yet we tend to assume there must be some set of properties that make somebody lovable. After all, if we don’t have reasons why we love someone, then our love is irrational, and if those reasons aren’t properties of the beloved, then it seems we don’t love them but something else. In philosophical jargon, we assume that romantic love is erosic. To say that love is erosic is to say that it’s something we feel in response to the features of the beloved.

So, let’s say you’ve got your list together, or at least you could make such a list given enough time. Now imagine that you and your partner are touring a new cloning factory, which uses mind-blowing new technology to produce perfect living duplicates of any person. Your partner is so amazed by it all that they lose their footing and fall into the cloning machine. There’s a flash, a zap, and suddenly two of your partner walk out of the machine! They’re identical in every respect: same memory, same personality, same appearance. Everything on your list applies to both of them.

So what happens now?

It seems things could go two ways. Either you find that you’re in love with the clone too, or you don’t. Both options are troubling. If you do fall in love with the replica, then it seems that romantic love isn’t exclusive. There can in fact be two or more of your one-and-only. That’s fine, you might reply: people can be in love with more than one person at once, even when they’re not clones. And yet if we’d fall in love with anyone else who had the same properties our beloved has, do we actually love our beloved themselves, or just a set of properties? Do you love your beloved for their sense of humour, or do you just love a sense of humour that someone else might have as well?

On the other hand, what happens if you don’t fall in love with your lover’s doppelganger? That may sound more romantic, as if only the ‘real thing’ will suffice. If you believe in souls, this is probably the answer you’re looking for: it’s the soul of the beloved you love, and no matter how similar, the clone can’t have that. But what is it to love a soul, if not to love the properties of the person whose soul it is? And what if there just are no such thing as souls anyway?

When I run this cloning accident thought experiment past students, they often appeal to shared history. You’ve known your partner for however long, whereas the clone has only just popped into existence. Yet the clone has exactly the same memories as the original. You’ve probably seen couples, particularly older ones, who have a habit of remembering past experiences in tandem. They each add details the other has forgotten and correct each other’s recollections, thereby helping to fill out the story. The couple forms what’s called a ‘transactive memory system’. In our cloning scenario, you could form such a system with the clone just as easily as you could with the original. You can reminisce with the clone about things the clone, strictly speaking, never did, but still seems to remember. All three of you will always have Paris.

The point of this rather outlandish story is not that you should or shouldn’t fall in love with clones. (Who am I to tell you what to do?) Rather, it’s to highlight some of the problems that emerge as soon as we try to say what romantic love is. Either you love the properties of the person, in which case love isn’t exclusive and arguably isn’t love of the person, or you don’t love a person for their properties, in which case love isn’t based on reasons. It can be erosic, or exclusive, but not both. This is the bind that’s come to be known as ‘Gellner’s Paradox’.

There are other, related problems too. Consider the way romantic love can survive changes, often quite radical ones, in someone’s properties. You may fall in love with a carefree, even wild young thing, then look up forty years later to find you now love a mature, dependable, serious middle-ager. If love is a response to the other’s properties, then shouldn’t you have stopped loving this person when their properties changed? And yet it only takes a few poignant moments of watching someone caring for a partner whose personality has been savaged by illness or injury to see that love can indeed survive such changes.

There is at least one way out of Gellner’s Paradox. You’re probably not going to like it though.
The philosopher Stan van Hooft (a colleague of mine and a fine jazz bassist to boot) came up with a way of steering around Gellner’s Paradox that’s at once ingeniously simple and rather unsettling. Van Hooft’s insight is that falling in love largely seems to happen behind our back. By the time we realise we’re falling in love, we’ve already been falling for a while. To commit yourself to love, on this telling, is not so much to simply choose to love someone – how would you even do that? – but to endorse the fact you’ve already, on some level, chosen. We find ourselves committed. You can then either assent to that commitment or try to resist it, but it’s there.

So by the time you realise you’re in love, you’re already hooked. The question is, what hooked you? This is where we came in, trying to make a list of the properties you love about someone. Van Hooft’s clever move here is to shift from metaphysics to epistemology, from the nature of what is to what we can know. Perhaps we do, in fact, love the beloved for reasons, but it may be that we just don’t know what those reasons are. You might think you love someone because they love dogs and have a great sense of fun, but actually love them for some other set of reasons you don’t even suspect. So when you don’t stop loving them when they develop an allergy to dogs and become serious and staid, or when they fall into a cloning machine and you find you don’t love their replica, there’s no problem: whatever it is you love, it’s still there.

(In the clone case of course it’s even more mysterious. What property could the clone have that the original lacks? But that’s the whole point of shifting to epistemology here: so long as we don’t know the reasons of love, then love might be rational, and Gellner’s Paradox can’t get off the ground).
Clarence ‘Frogman’ Henry had a 1961 hit singing “I don’t know why I love you, but I do.” Perhaps that’s actually how love is for everyone – and perhaps that’s just as well.

From the Love edition, available in print or digital format here. Subscriptions also available to New Philosopher worldwide in print and digital here.