To affirm life is to deepen, to make more inward, and to exalt the will-to-life. At the same time the man who has become a thinking being feels a compulsion to give every will-to-live the same reverence for life that he gives to his own. He experiences that other life as his own. He accepts as being good: to preserve life, to raise to its highest value life which is capable of development; and as being evil: to destroy life, to injure life, to repress life which is capable of development. This is the absolute, fundamental principle of the moral, and it is a necessity of thought.
Albert SchweitzerVery little of the great cruelty shown by men can really be attributed to cruel instinct. Most of it comes from thoughtlessness or inherited habit. The roots of cruelty, therefore, are not so much strong as widespread. But the time must come when inhumanity protected by custom and thoughtlessness will succumb before humanity championed by thought. Let us work that this time may come.
Albert Schweitzer