'Pends on your preference.
Love can be reduced to its neurological-somatological (brain-body) processes. The flighty feelings that make y'heart feel all fluttery 'n such. Etc.
Or, it can be a form of seeing -- seeing the whole person without particulars, beyond the particulars (hands, smile, hair, temper, distaste, etc.).
Or, will-to-good (or bene-volence).
Fundamentally, however, love is founded in relation.
I'll take all four, personally. The second is a requisite; the third is its fulfillment; the first is its result; the fourth is the entire process.
"I love you," that is, "I see you, will the best for you, and am rewarded biologically because of this." Willing the best, oftentimes, means nothing more than seeing -- and seeing entails the language expressed by the one seen.
Of course, love often doesn't mean this. Love as affection can mean the simple affective responses associated with external stimulii. A boy who watches a man work on his garden every sunday may feel affection for him without even having relation with him. This form of love can quite often be based on a particular, partciularly behavioristically: the person doesn't always love the person in his or her entirety, but an aspect of them (their smile, something in their history). Or, love may mean friendship, in which case two individuals come together unintentionally through their intersecting points of interest: they both like bowling -- and so they spend time together by virtue of this shared interest. Erotic love is the love people "fall" in, the love that breaks hearts, inspires poetry (and b*tchiness). There is a higher form, though, that I consider unconditional.
Most of these loves overlap. Erotic love necessarily entails affection, and oftentimes friendship (but think of marriages centuries ago wherein both partners were planned together; their roles in marriage were more functional than affectively related). Friendship doesn't always have to involve affection (which is typically why we care less for our friends than for our families). The interesting thing is that the highest love -- which I can think only in the religious form of agapas -- can live without any of the other three forms. This form of love is love constituted and sustained through the nakedness of one's will. That is to say, agapas is the will in the will-to-good of benevolence. Without it, love limits itself to spontaneity; the person loves because his inclinations force these feelings on him. His love is limited to his mood, in short.
So, love has typically one of four forms at least, though oftentimes these forms can overlap. These forms differ in their makeup: affection and erotic love are often primarily based in neurological-somatological processes; they are the loves that "grab" you before you think of grabbing them. Friendship is more spiritual, if you will; it can and often does exist without an affective base, mostly because friendship is a byproduct of shared interests. The highest love, unconditional love, love with a will, agapas, is, yes, what keeps these three lower loves alive. Spontaneous love is determined love; determined love can just as easily turn to hatred -- unless a will is present. And not just any will -- a will that wills a the paradox of selflessness: resigning oneself for the sake of another, only after which one gains the happiness through the sustained being of these other three lower loves.
