Compassion for animals is intimately associated with goodness of character, and it may be confidently asserted that he who is cruel to animals cannot be a good man.
Arthur Schopenhauer, The Basis of Morality
If I recall correctly, Schopenhauer explained that compassion (feeling for the other, sympathetic concern, meeting the other just where the other is, without judgment, love) was the root of the “goodness” of a person, indeed of mankind.
One wonders about this: Were we to realize a proper understanding, a compassion for animals we might find ourselves being more understanding, compassionate, toward our fellow human beings. The understanding of compassion flows not from the world of man, but from the world of man’s understanding and compassion for animals. The tendency of compassion which is easily identified. The evolution of compassion moves from the concern for the least of us to all of us,