Suffering is not only physical pain. It can include fear, distress, hunger, grief, loneliness, confusion, humiliation, confinement, exhaustion and deprivation.
Suffering matters because it is experienced. It is not an abstract statistic to the being who suffers. A conscious being’s suffering has moral weight even when that being cannot explain it in words.
Not all suffering can be removed, and not every reduction of suffering is simple. Some choices involve competing harms. But avoidable suffering should not be ignored merely because it is familiar, hidden, profitable or inconvenient.
Evidence notes
Evidence about suffering can come from behaviour, physiology, testimony, medical knowledge, animal welfare science and lived experience.
Ethical questions
When suffering can be reduced without creating greater harm, what reason is there to ignore it?
Conclusion
Suffering is morally serious because it is a real negative experience. Any ethical system must explain how it treats suffering and why.