Biology and Philosophy of Love
What does it mean to love another person? This question is one that virtually every person has asked himself at some point; virtually every school of thought that exists has attempted to provide an answer of some sort. In this paper I will explain my own attempt at answering that question, from the perspective of an amateur philosopher; then I shall delineate the answers that some biologists have given. We shall see that, while at first these two sets of answers might appear to be quite different, there are in fact some interesting and notable similarities.
I have heard many different accounts of what it is to love someone - to care truly for that person's best interest, to be willing to sacrifice one's own life for that person's well-being, and so on, the list is infinite. To be sure, these accounts all have a measure of validity; there are many different forms of love. However, there is one aspect that all of them have in common, which is the same point at which I think they fail to capture what it really is to love someone: they are too altruistic. Humans, it seems to me, are essentially self-centered creatures; and I do not intend that statement to have the extreme negative connotations that usually accompany the term "self-centered". I mean it in the most literal sense: humans are centered around the self. Much as we may try, the self is un-transcend-able. At this point in scientific and spiritual progress, we cannot ever truly experience anything through another person's frame of reference - all that we can know for certain is that which we think and feel. Thus, it makes no sense to speak of love as a sort of "leaving the self".
How, then, are we to think about it? I offer this alternative: so as to avoid the mistake of treating love as a form of altruism, we should think of loving another person as the act of loving oneself through another person - in other words, we love the people that make us feel best about ourselves, that bring out the best in ourselves. It is important to note that by no means does this definition entail that we do not genuinely care about the people we supposedly love. We can see this as follows: by this definition, it is essential that we like the people we love (it would be impossible for someone I did not like truly to make me feel good about myself); we want the people we like to be happy; we are best suited to making other people happy by being happy ourselves; we cannot be happy unless we like ourselves. And how can we accomplish this feat? By seeking out the company of those people who, for whatever reason, make it easier to like ourselves. Upon reflection, this account seems to me to be the only one that allows us to love others without requiring that love to be a pure act of altruism.
And what does biology have to say about love? First of all, it seems to be widely agreed amongst biologists who study the subject that love is an essential part of human functioning. Dr. Arthur Janov, author of The Biology of Love, brings up a developmental fact essential to understanding this point: "The right hemisphere, which is larger than the left, is the site of feelings and emotions and of holistic, global thinking. Thoughts, planning, and concepts are the domain of the left hemisphere. The right brain is largely mature at the second year of life; the left brain is only beginning its maturation at that time. Feelings pre-date thoughts. In terms of evolution we are feeling beings long before we are thinking ones." (1)  Furthermore, it has been shown that neglect, or lack of love, has a serious impact on human ability to survive and develop properly. (2)  Dr. Janov notes that infants who are neglected have brains that are significantly different from normal brains: the number of stress-hormone receptors, for example, are much lower in the brain of a neglected infant, which entails a higher level of stress - and therefore unhappiness - in that person. (1) 
Biology, as of this point in time, has successfully determined what processes exactly occur in the brain when one loves another person. However, there are studies that have been done that show some interesting correlations. Dr. Helen Fisher posits a dramatic increase in the amount of dopamine and norepinephrine present in the brain when one first becomes infatuated with another person, which would account for the feelings of euphoria, giddiness and so on that one would experience at that point. (3)  Another study showed that, in the brains of people who had recently fallen in love, serotonin levels were significantly higher than those in the brains of the control group. (4)  Yet another study demonstrated the possibility of a correlation between the ability of adults to bond emotionally with one another and the presence of the hormone oxytocin, which is normally associated with human reproductive processes such as lactation and, interestingly, male and female orgasm. (5) 
How can these findings be applied to my theory as outlined above? Most notably, there is a correlation between the notion of loving another person as a form of self-love and the types of chemicals that scientists have found to be present in the brains of people who are in love. All of the chemicals stated above are associated not only with being in love but with other forms of gratification. Oxytocin, as stated above, is released in the brain during orgasm; dopamine is associated with pain relief (6)  and euphoric feelings in general, as is evidenced by the role it plays in the effects of amphetamines and cocaine; serotonin is associated with feelings of calm and happiness. In other words: when we are in love, chemicals associated with pleasure are released into our brains; loving another person is comparable to self-gratification. To love another person in the philosophical sense is to love oneself; to love another person in the biological sense is to give oneself pleasure.
References1. The Biology of Love ; online excerpt of Dr. Janov's book
3. interview with Dr. Helen Fisher 6. article on chemical nature of pain and pleasure