Love is another of those non-physical concepts. Love is a commitment and not just mushy feelings. Commitment is another, non-physical, unmeasurable concept. There is not a "love" receptor in the brain. There might be a complex, biochemical cascade in the brain that correlates with the experience of love, but there is more than the physical experience going on. We have a brain, but we also have a mind, or, a soul. It's a word to describe that non-material part of us, our essence.
Where does this immaterial essence come from? How can the physical produce the non-physical? It can't. We come to a philosophical wall, something science can't ascend, because the topic has left the realm of the material. Good. Love. Beauty. These things do not belong to science, because these belong to the mind, the soul, the spirit, that part of us that is not physical. And since we know these things, then we know something about the existence of that which is spiritual. If love is a spiritual concept, understood by spiritual beings, then we need to turn to someone other than the scientist to explain these experiences, if one is interested in explanations. This brings us to philosophers, of whom theologians are a sub-discipline. I bring up theologians, because of my following assertion.
Because we know of love, we know that God exists.I did not say we all have experienced love. Some of us know the lack of love, or neglect, and crave love. Somehow we know it's shape, spiritually. We can respond to love. We also respond to its lack, which can undo all satisfied physical needs. People do seem to die of broken hearts, despite physical health.
The Bible tells us God is love, 1 John 4:8. This seems to be unique to Christianity compared to other philosophies that try to explain our souls. This concept is compelling to me. It might not be to those who read this, but I feel, having a soul experience here, that cracking open that door of thinking, leads to a flood of thoughts, that I can't possibly put down with any coherence in one evening's blog post. But the beloved apostle, John, did write some great stuff in his first epistle.
Ladies and gentlemen, I recommend 1 John, all 5 chapters, to learn about love and light and truth, and those things that we scientists can't explain scientifically.