Whether animals have the capacity to reason or talk is irrelevant to how we should treat them
The day may come when the rest of animal creation may acquire those rights which never could have been withholden from them but by the hand of tyranny. The French have already discovered that the blackness of the skin is no reason why a human being should be abandoned without redress to the caprice of a tormentor. It may one day come to be recognized that the number of legs, the villosity of the skin, or the termination of the os sacrum are reasons equally insufficient for abandoning a sensitive being to the same fate.
What else is it that should trace the insuperable line? Is it the faculty of reason, or perhaps the faculty of discourse? But a full-grown horse or dog is beyond comparison a more rational, as well as a more conversable animal, than an infant of a day or a week or even a month old.
But suppose they were otherwise, what would it avail? The question is not, Can they reason? nor Can they talk? but, Can they suffer?
How it is that animals understand things I do not know, but it is certain that they do understand. Perhaps there is a language which is not made of words and everything in the world understands it. Perhaps there is a soul hidden in everything and it can always speak, without even making a sound, to another soul.
I no longer steal from Nature
You are diseased in understanding and religion. Come to me, that you may hear something of sound truth.
Do not unjustly eat fish the water has given up, And do not desire as food the flesh of slaughtered animals, Or the white milk of mothers who intended its pure draught for their young, not noble ladies.
And do not grieve the unsuspecting birds by taking eggs; for injustice is the worst of crimes.
And spare the honey which the bees get industriously from the flowers of fragrant plants; For they did not store it ...