It's also undefinable because it means different things to different people; debates on whether 'love' 'exists' are therefore meaningless, in my opinion, because each person is debating whether what they believe to be love exists and what they each believe may not be at all congruent.
'Love' as an emotion, like all emotions, is linked to chemical reactions occurring in the brain. It's oversimplistic to say that it is a chemical reaction: it's a product of chemical reactions, which themselves may be stimulated by any number of factors. Besides that, breaking any feeling down to its chemical constituents just seems to be me like "greedy reductionism".
anon_nymouz
labeling something we dont' understand and claim it to exist...
...is something done on a regular basis by many groups of people. Newton labelled gravity, the mechanism of which he did not understand, and claimed its existence based on evidence. Just because something is not understood does not mean that it does not exist: you first have to define something before you can start proving or disproving its existence and before you can understand it.
Gravity is also not something that can be touched, tasted, smelled, heard or seen, yet I'm sure most people will contend that it exists.