The word “love” can have a variety of related but distinct meanings in different contexts. Often, other languages use multiple words to express some of the different concepts that English relies mainly on “love” to encapsulate; one example is the plurality of Greek words for “love.” Cultural differences in conceptualising love thus make it doubly difficult to establish any universal definition.

Although the nature of love is a subject of frequent debate, different aspects of the word can be clarified by determining what isn’t love. As a general expression of positive sentiment (a stronger form of like), love is commonly contrasted with hate (or neutral apathy); as a more emotionally intimate form of romantic attachment and as an interpersonal relationship with romantic overtones, love is sometimes contrasted with friendship, although the word love is often applied to close friendships.

When discussed in the abstract, love usually refers to interpersonal love, an experience felt by a person for another person. Love often involves caring for or identifying with a person or thing (cf. vulnerability and care theory of love), including oneself (cf. narcissism).

In addition to cross-cultural differences in understanding love, ideas about love have also changed greatly over time. Some historians date modern conceptions of romantic love to courtly Europe during or after the Middle Ages, although the prior existence of romantic attachments is attested by ancient love poetry.

Because of the complex and abstract nature of love, discourse on love is commonly reduced to a thought-terminating cliché, and there are a number of common proverbs regarding love, from Virgil’s “Love conquers all” to The Beatles’ “All You Need Is Love”.

St. Thomas Aquinas, following Aristotle, defines love as “to will the good of another.” Bertrand Russell describes love as a condition of “absolute value,” as opposed relative value. Philosopher Gottfried Leibniz said that love is “to be delighted by the happiness of another.Biologist Jeremy Griffith defines love as “unconditional selflessness”

Love is sometimes referred to as being the “international language”, overriding cultural and linguistic divisions.

Impersonal love
A person can be said to love an object, principle, or goal if they value it greatly and are deeply committed to it. Similarly, compassionate outreach and volunteer workers’ “love” of their cause may sometimes be born not of interpersonal love, but impersonal love coupled with altruism and strong spiritual or political convictions.

People can also “love” material objects, animals, or activities if they invest themselves in bonding or otherwise identifying with those things. If sexual passion is also involved, this condition is called paraphilia.

Interpersonal love
Interpersonal love refers to love between human beings. It is a more potent sentiment than a simple liking for another. Unrequited love refers to those feelings of love that are not reciprocated. Interpersonal love is most closely associated with interpersonal relationships.Such love might exist between family members, friends, and couples.

Throughout history, philosophy and religion have done the most speculation on the phenomenon of love. In the last century, the science of psychology has written a great deal on the subject.

In recent years, the sciences of psychology, anthropology, neuroscience, and biology have added to the understanding of the nature and function of love.

Chinese and other Sinic cultures
Two philosophical underpinnings of love exist in the Chinese tradition, one from Confucianism which emphasised actions and duty while the other came from Mohism which championed a universal love. A core concept to Confucianism is Ren (“benevolent love”, 仁), which focuses on duty, action and attitude in a relationship rather than love itself. In Confucianism, one displays benevolent love by performing actions such as filial piety from children, kindness from parent, loyalty to the king and so forth.

The concept of Ai (愛) was developed by the Chinese philosopher Mozi in the 4th century BC in reaction to Confucianism’s benevolent love. Mozi tried to replace what he considered to be the long-entrenched Chinese over-attachment to family and clan structures with the concept of “universal love” (jiān’ài, 兼愛).

In this, he argued directly against Confucians who believed that it was natural and correct for people to care about different people in different degrees. Mozi, by contrast, believed people in principle should care for all people equally.

Mohism stressed that rather than adopting different attitudes towards different people, love should be unconditional and offered to everyone without regard to reciprocation, not just to friends, family and other Confucian relations.

Later in Chinese Buddhism, the term Ai (愛) was adopted to refer to a passionate caring love and was considered a fundamental desire. In Buddhism, Ai was seen as capable of being either selfish or selfless, the latter being a key element towards enlightenment.

In contemporary Chinese, Ai is often used as the equivalent of the Western concept of love. Ai is used as both a verb (e.g. wo ai ni 我愛你, or “I love you”) and a noun (such as aiqing 愛情, or “romantic love”). However, due to the influence of Confucian Ren, the phrase ‘Wo ai ni’ (I love you) carries with it a very specific sense of responsibility, commitment and loyalty.

Instead of frequently saying “I love you” as in some Western societies, the Chinese are more likely to express feelings of affection in a more casual way. Consequently, “I like you” (Wo xihuan ni, 我喜欢你) is a more common way of expressing affection in Chinese; it is more playful and less serious.

This is also true in Japanese (suki da, 好きだ). The Chinese are also more likely to say “I love you” in English or other foreign languages than they would in their mother tongue.

Persian love
Rumi, Hafiz and Sa’di are icons of the passion and love that the Persian culture and language present. The Persian word for love is eshgh derived from the Arabic ishq, however is considered by most to be too stalwart a term for interpersonal love and is more commonly substituted for ‘doost dashtan’ (‘liking’).

In the Persian culture, everything is encompassed by love and all is for love, starting from loving friends and family, husbands and wives, and eventually reaching the divine love that is the ultimate goal in life[citation needed]. Over seven centuries ago, Sa’di wrote:
The children of Adam are limbs of one body
Having been created of one essence.
When the calamity of time afflicts one limb
The other limbs cannot remain at rest.
If you have no sympathy for the troubles of others
You are not worthy to be called by the name of “man”.

Japanese love
In Japanese Buddhism, ai (愛) is passionate caring love, and a fundamental desire. It can develop towards either selfishness or selflessness and enlightenment. Amae (甘え), a Japanese word meaning “indulgent dependence,” is part of the child-rearingculture of Japan. Japanese mothers are expected to hug and indulge their children, and children are expected to reward their mothers by clinging and serving.

Some sociologists have suggested that Japanese social interactions in later life are modeled on the mother-child amae.

Philosophical views on love
Philosophy of love is the field of social philosophy and ethics which attempts to explain the nature of love. The philosophical investigation of love includes the tasks of distinguishing between the various kinds of personal love; asking if and how love is/can be justified; asking what the value of love is; and what impact love has on the autonomy of both the lover and the beloved.

There are many different theories which attempt to explain what love is, and what function it serves. It would be very difficult to explain love to a hypothetical person who had not himself or herself experienced love or being loved. In fact, to such a person love would appear to be quite strange if not outright irrational behavior.

Among the prevailing types of theories that attempt to account for the existence of love there are: psychological theories, the vast majority of which consider love to be very healthy behavior; there are evolutionary theories which hold that love is part of the process of natural selection; there are spiritual theories which may, for instance consider love to be a gift from God; there are also theories that consider love to be an unexplainable mystery, very much like a mystical experience.