We know the cost to the reality of life through deprivation of love. Human beings, other sentient creatures and all of life suffers through withdrawal of love, abuse and violence.
Science has eliminated love from its analysis of reality. Science perceives reality through the limited constructs of the mind. You will rarely find the word love in scientific textbooks. We cannot know ultimate reality though highlighting the mind and dismissing the heart or vice-versa.
The Buddha made frequent reference to metta with its three-fold meaning of love, kindness and friendship according to context. He made powerful statements on love – Metta is a Brahma Vihara (literally Abiding/Dwelling with/in God).