Talk to me about it in term of chemistry and chemicals in our brain then. What you seem to be getting at--and I concede that I'm only assuming so at this point--is the whole "you just know it" mantra. But to be honest, to me, it seems like you're just begging the question. For example, you may get to know a girl, and have these overwhelming feelings rush into your mind about her, and you may say that is love. But the problem here is that you're already making a judgement call that what you feel is indeed love. But you do that without knowing what love is. So if you mean to suggest, "Don't think about it too much; you'll just know!" Then the problem is that if you don't know what it is that you're supposed to feel, you can never be sure if what you feel IS that thing.
Love is a broad term, and it has a different definition for everyone.
Take, for example, my recent crush that I mentioned few posts ago. If you were to ask me to define my crush in terms of love. I'll say that I love the way she looks, and carries herself.
For my best friend that I also mentioned, I'll say that I love her because she's been with me through the darkest hour in my life, and she's someone I can talk to about anything, someone who's company I cherish.
On the other hand, I had this Abuses will lead to ban GF. And I hated more things about her than I loved, but she was still my GF and I was deeply upset after breaking up with her. Confusing, right?
It's all psychological and chemical. For me, if I have to ask myself "Am I in love?", then I'm not. When I'm in love, I can feel it my gut and my chest.
For me, it is near impossible to develop THAT love after friendship. A wehshi crush is a pre requisite to falling in love, for me. For you, it may be different. So in short, there are some questions that are better left unanswered.