When asked the question, “what is love?”, we often describe a feeling; the love we have have for our children, our partner, or a cherished pet. A powerful happiness and connection we feel in the presence of this other being which transcends circumstance, as solid and certain as the Earth yet intangible in the same way that a color is indescribable. A warmth in the mind and body, a desire to be close to and care for that one. With love we feel more whole and alive.
Other times, we extend this sense to places, things, activities, etc for which we have a particularly strong affinity: “I love to dance”, “I love this dress”, “I love Paris”. In this way, we casually invoke the core experience of love, the warmth and joy that arise within us and seem to fill us up.
But there is a deeper aspect of love; the subject of every major religion and many wonderful spiritual movements. The Love of God which we are admonished to seek and aspire to, the Love from which all compassion flows and which permeates all of life and the universe. We are told that God is love, that love is all we need, that love is all that there is.
Simply put, love is an identification with, and of, the singular unity of which all things are whole within. You, I, everyone we know, every other person, place or thing which is known and unknown; even every thought and expression; all are a unity and that unity is what we experience as God. When we love a person, we are identifying them with the unity and thus accepting them as part of ourselves. So when we are told “Thou shalt love they neighbor as thyself”, we can extrapolate it to mean, “accept that your neighbor is a part of you, just as your nose is a part of face.”
When we “love” the feeling of a warm shower, we are, through the experience, being brought in to the presence of the moment. In such a state of mind, we are drawn close to the unity of all things and a simple shift of awareness could bring us in to a conscious contact with the divine.
The devout and religious may find no fault in these observations and looking deeply into any of their traditions they will find this truth writ millions of different ways. For the more scientific of us, only slightly more explanation may be needed. I am no quantum theorist so I dare not tread the roads that lead through entanglement. Rather, I would consider a quote from Carl Sagan:
"If you wish to make an apple pie from scratch, you must first invent the universe."
- Carl Sagan; Cosmos
That is to say that everything of the present arose from and is ever emerging from all that came before. This is one gateway to the conception of unity, a common genesis. For an explanation beyond that, you might try your luck with those fellows over at CERN or you might try to stop looking and simply see.