Love is an emotion of strong affection and personal attachment. In philosophical context, love is a virtue representing all of human kindness, compassion, and affection. Love is central to many religions, as in the Christian phrase, "God is love" or Agape in the Canonical gospels. Love may also be described as actions towards others (or oneself) based on compassion, or as actions towards others based on affection.
In English, the word love can refer to a variety of different feelings, states, and attitudes, ranging from generic pleasure ("I loved that meal") to intense interpersonal attraction ("I love my partner"). "Love" can also refer specifically to the passionate desire and intimacy of romantic love, to the sexual love of eros (cf. Greek words for love), to the emotional closeness of familial love, or to the platonic love that defines friendship, to the profound oneness or devotion of religious love. This diversity of uses and meanings, combined with the complexity of the feelings involved, makes love unusually difficult to consistently define, even compared to other emotional states.
Love in its various forms acts as a major facilitator of interpersonal relationships and, owing to its central psychological importance, is one of the most common themes in the creative arts.
Helen Fisher defines what could be understood as love as an evolved state of the survival instinct, primarily used to keep human beings together against menaces and to facilitate the continuation of the species through reproduction.
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 conceptualizing love thus make it doubly difficult to establish any universal definition.
Although the nature or essence 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 less sexual and more emotionally intimate form of romantic attachment, love is commonly contrasted with lust; 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 to relative value. Philosopher Gottfried Leibniz said that love is "to be delighted by the happiness of another."
Love is sometimes referred to as being the "international language", overriding cultural and linguistic divisions.
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 borne 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 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. There are also a number of psychological disorders related to love, such as erotomania.
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 evolutionary psychology, evolutionary biology, anthropology, neuroscience, and biology have added to the understanding of the nature and function of love.