One of the strange things about asking the question ‘what is love?’ today is that many people in the Western world are uncomfortable even with the attempt to define it. A philosophy of love, according to this view, is a contradiction in terms. For love is a matter of feeling, not thought. It can’t be defined; or, if it can be defined, then the very attempt to do so ends up denaturing precisely what we are trying to understand.

At the same time, talk of love is obviously everywhere. Our world is awash with explanations of why and how we love, in terms of mating strategies and evolutionary fitness, or needs for intimacy and benevolence, or brain states and neuro-transmitters, or patterns of attachment in childhood.

So why the inconsistency? Why can we hardly stop talking about love and yet at the same time remain reluctant to ask what it is — to define it?

The answer, I suggest, is that, since the end of the 18th century, love in the Western world has increasingly taken on the role of a new god. And, as we will see, not any old god — not, say, one of those self-seeking, lustful and capricious Greek gods — but rather the spitting image of the Christian God, who loves in the manner of agape.

This is why it is regarded as acceptable, indeed vital, to ask how love (whatever love is) can be made to work, under what circumstances it doesn’t succeed, what social or evolutionary ends it might serve, whether it works best inside marriage or outside, whether women are better at it than men and what sort of therapies might best promote it. But fundamentally to question what love is in the first place is, for many people, a question too many.

For those who hold this view, it is self-evident that genuine love must be unconditional, just as divine agape is taken to be— in the sense that it is neither aroused nor diminished by the other’s value or qualities; and that it is not fully love unless it is enduring, disinterested and loves the other for his or her own sake and in all his or her particularity.

In this spirit, Harry Frankfurt, one of the few philosophers these days who writes on love, claims, deeply conventionally, that love ‘consists most basically in a disinterested concern for the well-being or flourishing of the person who is loved. It is not driven’, he adds, ‘by any ulterior purpose, but seeks the good of the beloved […] for its own sake.’

Another secular philosopher, Irving Singer, claims that genuine love is a gratuitous ‘bestowal’ of value, not based merely on ‘appraisal’ of the qualities of the loved one. Like divine agape, it bestows value on others spontaneously and regardless of their specific qualities. Indeed, Singer then uses this concept of bestowal as a standard to criticise any thinker, such as Plato or Aristotle, who argues that love is fundamentally a response to the value that the lover sees in the loved one – value such as beauty, or virtue, or goodness.

Not surprisingly, this view of love makes it impossible to say why we love one person (or one work of art, or landscape, or vocation) rather than another, or what inspires love. As Frankfurt puts it, A loves B in virtue of ‘her whole lovable nature […] that inexplicable quality of which I cannot give an account’. In a similar vein, Alexander Nehamas, another distinguished philosopher, concludes an analysis of friendship-love by citing with complete approval Montaigne’s famous non-explanation of why we love: ‘If you ask me why I love him, I can only say, ‘Because it was him, because it was I’.’

Paradoxically, over the past century, this conception of love as fundamentally unconditional has become stuck in a time warp at the same time as attitudes to the practice of love have become vastly freer. Though we have seen great revolutions in divorce, contraception, feminism and homosexuality, they have tended to assume this dominant way of thinking about what genuine love should be, rather than to generate new ways of thinking about it.

With one crucial proviso: romantic or marital love is, I suggest, inexorably being supplanted by parental love as the highest — the most sacred — expression of love so conceived. The child, rather than the romantic lover or the spouse, is increasingly taken to be the privileged object of a love conceived as quintessentially unconditional, disinterested, unchanging and affirming of the loved one in all his or her particularity. Though romantic love is far from dead, it is no longer going to be the supreme instance of love, that touchstone of the highest, freest, most unconditional love, without which one’s life cannot be deemed to be complete or truly flourishing. And to that extent, the long Romantic era, which began in the late 18th century, is slowly coming to an end.

I’m going to park the matter of how human love came to be seen as our new god and, at the same time, to be modelled on how the Christian God is often said to love and return to the question: is love definable? The answer is that for most of the last 2,400 years almost no major thinker doubted that it is.

In a short essay, I cannot do more than point to some of the answers that have been given to this question, but suffice it to say there have been six principal theories of love since Hebrew scripture and Greek thought, the twin sources of Western love, all of which very much address just this question: what exactly inspires love? Very briefly, and therefore over-simply, here are their answers.

First, for much of the Hebrew and Christian tradition, we love our neighbour for the sake of God — in other words, because we love God and because God commands it; because our neighbour is, like us, made in the image of God, or belongs with us to a community of faith in God.

The second and third reasons why we love are both given by Plato. They are because we wish perpetually to possess the beauty we see instantiated in someone in order to create in beauty; and because we see in our loved one our unique other half, with whom we hope, in some sense, to find completion — a sense that, crucially, involves the experience of recovering an original state in which, together, we were whole.

Fourth, for Aristotle, genuine love – which he sees as perfect friendship, or philia – is rooted in, and inescapably conditional on, the characters of two people who are good and alike in virtue and who come to see each other as ‘second selves’. His answer to the question ‘why do we love at all?’ is that our flourishing — and good things that are needed in order to flourish, such as self-knowledge and, indeed, self-love — depend on such friendship-love. (Where, today, it is often said that you need to love yourself in order to love another, Aristotle suggests that you need to love another in order to love yourself.)

Fifth, there is the great and diverse line of naturalists, from Epicurus through Lucretius, Schopenhauer and Freud to contemporary evolutionary psychologists, who see love as the name for our idealisation of those whom we desire sexually, or to whom we are attached through a fundamentally erotic longing, whether for the sake of physical satisfaction or of reproduction. Their answer to the question ‘why do we love?’ is first, because all intense desire tends to idealise (as a result of which it is prone to wild delusions about the loved one); and, second, because such idealisation endows us with the tenacity to secure the one we desire, to endure the obstacles that often impede our doing so and to sustain the effort and fidelity needed to raise offspring.

Like all six of the major conceptions of love that have existed in Western history, this view goes back to the ancients. For example, we encounter elements of it in the Roman poet Lucretius, a contemporary of Julius Caesar writing in the first century BC, for whom sexual love is fundamentally violent, even a form of warfare, and results in unhappiness, delusion and dissatisfaction. The art of love, says Lucretius, is to enjoy this unscrupulous, manipulative instinct without getting hurt by it. Far from being a spiritual journey towards the absolute, lovers are easily incited to selfishness, stupidity and sadism. He doesn’t mince his words:

They squash the body they sought until it squeals And often their teeth make a gash on the lips.

In the course of affixing a kiss, which is hardly pure pleasure. They are indeed rather provoked to injure the object.

We are obviously a long way, here, from love as a search for heavenly beauty and goodness.

Nonetheless, these five definitions of love are not mutually exclusive. You can see love as a search for ideal beauty or goodness and as friendship between two individuals who see each other as second selves; and as the yearning for an other-worldly perfection; and as the desire for our other half; and as expressing the motives and virtues of neighbour-love; and also as sexual desire. These forms of relating might be in tension with each other, but this doesn’t mean that they cannot coexist in one relationship.

But – to return to my opening theme – there has been a sixth conception of love, which we owe to religious tradition, Jewish and Christian, and this concerns how God is said to love. Such love, like God Himself, is by definition unconditional, unchanging, absolute and capable of affirming everything about the loved one.

Much religious tradition has told us that, through God’s grace, this divine manner of loving could be infused into human beings, so that they could love like gods. In this way, genuine human love gets modelled on how God is said to love us — a model perfectly expressed by Pope Benedict XVI in his first encyclical, where he says that ‘God’s way of loving becomes the measure of human love.’ But religious tradition never held that humans have it in within their power to love in this full sense. To the question ‘why can human beings love in this divine way?’ the answer is clear: if they can do so at all, it is thanks to divine grace; it is because they are enabled by God. The great theologians of love, from Augustine to Martin Luther and beyond, are absolutely clear about this.

The disaster that love has suffered in the West for roughly the last two centuries is that, as belief in Christianity declined, this conception of how God loves increasingly came to be applied to unaided human love, especially by non-believers. As I suggested at the beginning of this essay, in doing so, love became a new god; a god, moreover, to whom we are all regarded as having access. Love that is unconditional and unchanging has come to be seen not just as the preserve of a handful of saintly figures who are privileged recipients of divine grace, but as within almost everyone’s power, unless they actively ‘resist’ it, or unless reality or pathology otherwise get in the way.

Whereas becoming a competent artist or gardener or editor or plumber or banker or singer is dearly purchased with long effort — and, even then, only by the few with sufficient talent — love has become widely seen as a democracy of salvation open to all.

So if love isn’t what it is generally taken to be — a sort of divinity in its own right, a divinity that can somehow make us humans into gods (as Martin Luther put it) — what is it?

I think love is something quite different to the six conceptions that have been put forward in Western history; and it is this: love is the rapture we feel for those who inspire in us the hope of an indestructible grounding for our life, those who give us a powerful sense of being at home in the world, of being ‘ontologically rooted’. As I suggested in my book Love: a history, we experience the loved one’s, ‘mere presence as grounding – or as a promise of grounding – because it seems to be receptive to, to recognise, to echo, to provide a powerful berth to what we regard as most essential about us. Which very much includes our origins – and the strengths, vulnerabilities, sensibility and fate with which they endow us. And which, far from being purely private, is deeply influenced by models that we absorb from our parents, society and peers.’

‘If we all have a need to love, it is because we all need to feel at home in the world: to root our life in the here and now; to give our existence solidity and validity; to deepen the sensation of being; to enable us to experience the reality of our life as indestructible (even if we also accept that our life is temporary and will end in death).’

That love involves a promise of grounding or rooting does not mean that it renders us static. On the contrary, it orients us towards a future opened up by that promise. The home that the other seems to promise us, the world to which their very presence beckons us and in relation to which we yearn to anchor our life, is not one that we have yet attained. (If it were, we would not fall so powerfully in love.) And so love is both deeply unsettling and deeply reassuring: for it draws us away from the comfortable familiarity of our life towards the promise of a more genuine home far beyond, and often terrifyingly beyond, our current habitat. Indeed, this multiplication of the possibilities of our being is what evokes that strange mixture of rapture and fear typical of all great love.

It is this self-interested rapture — at glimpsing in another the promise of finding a home in the world — that motivates the greatest self-giving of which we are capable. Contrary to ancient conventional wisdom, in genuine love there is no necessary conflict between self-interest and self-giving. Self-interest, far from being an inevitably narcissistic prison that renders us unable to see beyond our self, or that we can overcome only through the traumatic realisation that we might lose our loved one, is in fact indispensable to prizing open our vision and attention to the other – whose existence and flourishing become crucial to our own and who, in some ways, feels closer to us than we do to ourselves.

We are, I think, waging the wrong ‘god wars’ today. Dawkins, Hitchens and others have been fighting the last war: many if not most of their arguments against the ‘delusion’ of believing in an all-good, all-powerful, saving, creator-God have been around for at least a century or two. Both sides of the argument have well-rehearsed positions, to which little of any novelty has been added in recent years.

As importantly, the war itself is regarded as legitimate by all parties to it. It is acceptable, even honourable, to fight about whether God exists and whether belief in Him is good or bad for human flourishing.

But is it yet acceptable to throw open to the strongest doubt whether parents love their children unconditionally, or whether genuine love is selfless, enduring or affirms the loved one in all their particularity? Have we yet asked how much damage love as a religion is doing to human flourishing – and whether there isn’t a more realistic and successful way of conceiving this greatest of emotions? I suggest that we have barely begun to ask these questions.

This essay by Simon May was originally published under the title Love as Religion in Religion: Perspectives from the Engelsberg Seminar, Axess Publishing, 2020