If we believe that nature is cruel and unjust, or God is vengeful, does this then somehow serve as an excuse to justify our own barbarity? Is this the shortcut to our moral reasoning that whatever is "natural" or "of God" is (a) incapable of change and (b) okay to follow and emulate? If we believe that throughout the four-billion-year evolutionary history of life on Earth there was an adaptive survival strategy to the use of violence and that this then explains our "propensity" to it, or that God created the rest of living nature merely as a means to serve the human end, does this solidify our position now as immutable, therefore making the status quo more comfortable for us (especially if we are on the winning side) by making change not only unnecessary but impossible?
Let us for a moment imagine that we know nothing of our past. We know nothing of evolution or of the ways and wants of God. What then do we know? We know pain. We know it is something that when it occurs it is unpleasant and we want it to be discontinued and not to occur again. This is what we know of ourselves (if we are not masochists). When we experience something painful our behavior reveals our feeling of discomfort. If others act or react in a similar way, it is reasonable to infer that what they are experiencing is something undesirable. Even if humans or nonhuman animals are pretending to be in pain, they are still using that kind of behavior which experience tells them is indicative of those who are suffering pain. So whether we are actually in pain or just pretending to be in pain, our behavior reveals what pain looks like. In fact, all behavior (whether consciously or involuntarily expressing pain, pleasure, hatred or love) is an external illustration of an internal disposition in much the same way that the sounds and symbols a human would refer to as language and writing when describing her own species (but inane utterances and instinct when referring to nonhumans) are an external communication of an internal idea. We do not then like to experience those things which cause us harm and with sympathy and reason we can make the determination that others too do not like to have things done to them which cause them harm. This we know to be true of ourselves and others.
Now who but the most die-hard Cartesian1 would make the determination that a nonhuman animal does not experience pain in a similar way that a human does when she is reacting in a way not so different from how we would act in a comparable situation? We need not have any detailed knowledge of anatomy and physiology to know that when we see a dog or a cat or a cow or a bird limp or cry out vociferously in such a manner that is unusual for her normal way of being2 that the animal is in distress and experiencing something unpleasant and would, just as we would, desire it to be discontinued.
Why should we therefore deliberately cause suffering to another human or nonhuman being who is capable of suffering, when that suffering in no way contributes to that individual's well-being? Some may argue that the suffering caused is necessary to serve our (individual, "race", national, "species") end, whatever that end may be: be it to create wealth for us or protect ourselves from some real or misperceived danger or to serve as food. The question then arises, what makes our position in the universe more important than the position of those we inflict suffering upon? If moral progress or kindness or compassion is to have any meaning at all it must mean that we consider all beings' suffering, whether they walk on two legs or four legs, fly in the air, creep on the ground or swim in the water, as just as important as our own suffering. If something is absolutely necessary for our well-being, like food consumption, then let us consume in such a way that causes the least amount of suffering to others. If shelter and clothing are absolutely necessary then let us house ourselves and clothe ourselves in such a way that causes the least amount of suffering to other beings. Whatever the activity let us perform it with the same kind of mindfulness that causes the least amount of harm to other beings just as we ourselves desire to live a life where we experience the least amount of suffering to our own persons.
When once we gain a clear perception of the wrongness of causing harm to other beings, we ourselves will not only no longer want to take part in this injustice, but we will also seek to actively help those who are suffering. What criterion should we use to determine what kind of help we ought to employ? The criterion for all thought and action is that which accords with the demands of justice. Justice being defined, according to Martin Luther King Jr., as love correcting everything that stands against love3. If we have a surplus, or if we have the means and talents to help those who are not so fortunately endowed as we are, then the demands of loving justice make it incumbent upon us to do for them as we ourselves would like to have done for us under similar circumstances.
If this idea, this belief, this clear perception of the wrongness of causing harm to other beings and the rightness of helping those who are suffering becomes apparent to all people, then all people will no longer accept the injustice of doing otherwise. Slavery of humans is now understood to be a harmful institution, which we ought not subject one another to, because it was realized that using people merely as means to serve the ends of others is unjust. In the same way, our conception of the slavery of nonhuman animals to serve the human end, as an acceptable way to treat these sentient beings, cannot be maintained and will pass to oblivion because it is unjust. Injustice, like any imbalance, is not sustainable. A just weight is inevitable when we no longer express indifference to the suffering of those around us but use empathy and reason as a lantern to illuminate our path toward a more fair and caring world.
1 a follower of Rene Descartes, the seventeenth century philosopher and mathematician who suggested that nonhuman animals were simply mechanized automatons incapable of feeling
2 we can determine "normal way of being" for these individuals through prolonged observation using our five senses
3 p578 "Testament of Hope", 1991. The entire quote is " Power at its best is love implementing the demands of justice. Justice at its best is love correcting everything that stands against love."