The essence of love and compassion is understanding, the ability to recognize the physical, material, and psychological suffering of others, to put ourselves "inside the skin" of the other. We "go inside" their body, feelings, and mental formations, and witness for ourselves their suffering. Shallow observation as an outsider is not enough to see their suffering. We must become one with the subject of our observation. When we are in contact with another's suffering, a feeling of compassion is born in us. Compassion means, literally, "to suffer with."
No dogma taught by the present civilization seems to form so insuperable an obstacle in a way of a right understanding of the relations which culture sustains as to wilderness, as that which declares that the world was made especially for the uses of men. Every animal, plant, and crystal controverts it in the plainest terms. Yet it is taught from century to century as something ever new and precious, and in the resulting darkness the enormous conceit is allowed to go unchallenged.