I believe this principle is correct and that it requires us only to prevent what is bad and to promote what is good and it requires this of us only when we can do it without sacrificing anything that is, from the moral point of view, comparably important to one. This principle is correct because if it is in our power to prevent something very bad from happening, without thereby sacrificing anything morally significant, we should, morally, do it.
Singer then uses an example that I think is very effective. If I am walking past a shallow pond and see a child drowning in it, I should to swim and pull the child out. Although, This will mean getting my clothes muddy, but this is insignificant, while the death of the child would presumably be a very bad thing. Yes, this principle is correct because it suggest that we can help others to the extent that our well-being is not ultimately challenged. This can fundamentally change our world.
Someone might argue against it because alleviating poverty today may lead to greater suffering in the future. He uses Garrett Hardin’s example a lifeboat to compare the situation. “Where a rescue attempt may result in everyone going in. By reducing