“ Whatever my own practice may be, I have no doubt that it is a part of the destiny of the human race, in its gradual improvement, to leave off eating animals, as surely as the savage tribes have left off eating each other when they came in contact with the more civilized. ”
 Henry David Thoreau, Walden (1854). copy citation

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“True, he can and does live, in a great measure, by preying on other animals; but this is a miserable way,—as any one who will go to snaring rabbits, or slaughtering lambs, may learn,—and he will be regarded as a benefactor of his race who shall teach man to confine himself to a more innocent and wholesome diet. Whatever my own practice may be, I have no doubt that it is a part of the destiny of the human race, in its gradual improvement, to leave off eating animals, as surely as the savage tribes have left off eating each other when they came in contact with the more civilized.
If one listens to the faintest but constant suggestions of his genius, which are certainly true, he sees not to what extremes, or even insanity, it may lead him; and yet that way, as he grows more resolute and faithful, his road lies.” source

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