”As man advances in civilization, and small tribes are united into larger communities, the simplest reason would tell each individual that he ought to extend his social instincts and sympathies to all members of the same nation, though personally unknown to him. This point being once reached, there is only an artificial barrier to prevent his sympathies extending to the men of all nations and races. [If they appear different] experience unfortunately shews us how long it is before we look at them as our fellow creatures.
Sympathy beyond the confines of man, that is humanity to the lower animals, seems to be one of the latest moral acquisitions… This virtue [concern for lower animals], one of the noblest with which man is endowed, seems to arise incidentally from our sympathies becoming more tender and more widely diffused, until they extend to all sentient beings.”