Smith argues that we recognize the humanity of others by doing what?

Author and philosopher David Livingstone Smith has explored the act of dehumanization and how individuals demean others. He outlines the ways in which people are put down, either through physical enslavement or by simple forms of emotional oppression and dehumanization. The attitudes one has for another dictate how that individual is treated, and Smith recognizes the necessity of valuing individual humans and their lives.
According to his work, recognizing the humanity of others involves being saddened by the death of every individual on the planet, regardless of any personal characteristics they have, good or bad. In doing so, you have evaluated and understood their humanity. You know their internal life was intrinsically valuable, and there is grief in their demise. If they were a good person, you are saddened that a good life is gone, and if they were not, you are saddened that they no longer have the opportunity to change their ways. Recognizing humanity inherently means being distressed by its loss.