The question of perspective is one of the most important in philosophy today, and the way in which actions change depending on the alignment of objects is crucial to contemporary research into ethics.
Sam Harris and Peter Singer would appear to be at opposite ends of a spectrum. Singer is an ethical vegetarian and human-rights activist, a man who dedicates himself to philosophically grounding these beliefs. Harris is a staunch atheist, part of the Dawkins-Dennett Atheists Alliance, fond of arguing that Islam is "innately violent." But there is something about their method of argumentation that is deeply linked.
In his The End of Faith, which engages readers by discussing "religion, terror, and the future of reason" as if they were characters on Friends, Harris refers to the "moon illusion," or the mistaken belief held by some ancient societies that the moon was actually small, because it appears small from earth. He uses the moon illusion as an analogy to describe what he calls the "ethical illusion" of opposing torture as a institutional practice. It is much easier for us to endorse mass bombings than to endorse the torture of one person, which, according to Harris, could prevent the necessity of mass bombings and deaths. Therefore, he concludes, we should lift the veil and recognize the necessity of torture and the childishness of our bias against it.
In Astra Taylor's excellent documentary Examined Life, Peter Singer explains a thought experiment which he considers central to his theory. Suppose you are walking by a shallow pond in which a child appears to be drowning, and there are no other adults in sight. You are wearing nice shoes, and saving the child, although it would pose no bodily harm to you, would ruin the shoes. Would it not be reasonable to save the child anyway? Singer says that almost everyone he talks to responds that they would save the child despite ruining their shoes, so then Singer delivers the coup de grace: why would you not donate money to OxFam or UNICEF, which could just as easily save the lives of children, instead of spending your money on other things?
These analogies are like cotton candy: they are compelling, easy to manufacture, and ultimately unsatisfying and unhealthy. They each contain a kernel of truth: in Sam Harris' argument the fact that people fail to comprehend the enormity of actions such as mass bombings which require little exertion on behalf of the attacker, and in Peter Singer's argument the fact that people in late capitalism spend their money on useless drivel and that relief organizations could use the money. But their bogusness lies in collapsing these truths into cheap political sloganeering-- laypeople who agree with Harris can simply support waterboarding and Guantanamo as well as mass bombings, and laypeople who agree with Singer can simply donate a few bucks per paycheck to UNICEF while consuming all of the same products. These are not political solutions because they are responding to bad philosophy.