and most widely diffused because it pays the least attention to those characteristics deemed "valuable" or worthy of love and, as a result, is able to transcend most discriminating factors. Lewis describes it as a dependency-based love which risks extinction if the needs cease to be met. Affection, for Lewis, included both Need-love and Gift-love. He considered it responsible for nine-tenths of all solid and lasting human happiness. However, affection's strength is also what makes it vulnerable. Affection has the appearance of being "built-in" or "ready made", says Lewis, and as a result, people come to expect it irrespective of their behaviour and its natural consequences. Both in its Need and its Gift form, affection then is liable to "go bad", and to be corrupted by such forces as jealousy, ambivalence and smothering. Philia – friend bond Philia (Greek: φιλία) is the love between friends as close as siblings in strength and duration. The friendship is the strong bond existing between people who share common values, interests or activities. Lewis immediately differentiates friendship love from the other loves. He describes friendship as "the least biological, organic, instinctive, gregarious and necessary...the least natural of loves". Our species does not need friendship in order to reproduce, but to the classical and medieval worlds, it is a higher-level love because it is freely chosen. Lewis explains that true friendships, like the friendship between David and Jonathan in the Bible, are almost a lost art. He expresses a strong distaste for the way modern society ignores friendship. He notes that he cannot remember any poem that celebrated true friendship like that between David and Jonathan, Orestes and Pylades, Roland and Oliver, Amis and Amiles. Lewis goes on to say, "to the Ancients, Friendship seemed the happiest and most fully human of all loves; the crown of life and the school of virtue. The modern world, in comparison, ignores it". Growing out of companionship, friendship for Lewis was a deeply appreciative love, though one which he felt few people in modern society could value at its worth, because so few actually experienced true friendship. Nevertheless, Lewis was not blind to what he considered the dangers of friendships, such as its potential for cliquiness, anti-authoritarianism and pride. Eros – romantic love Eros (erōs, Greek: ἔρως) for Lewis was love in the sense of "being in love" or "loving" someone, as opposed to the raw sexuality of