Good question. It’s helpful to distinguish between absolute, objective, and subjective truths. A truth is objective if it is true independent of individual perspective, while a truth is absolute if it is true in all perspectives. Louis Pojman gives the following definitions for ethics:
- Moral absolutism: There is at least one principle that ought never to be violated.
- Moral objectivism: There is a fact of the matter as to whether any given action is morally permissible or impermissible: a fact of the matter that does not depend solely on social custom or individual acceptance.
In contrast, subjectivism or relativism only requires that an individual or a culture deem something as true (or wrong) in order for it to be true (or wrong). Infanticide is only wrong if I personally believe it to be wrong or if my society says it’s wrong.
An analogy with health and nutrition might be illuminating: It can be objectively bad for me to ingest peanuts if I have a peanut allergy. This is objectively true regardless of my beliefs. It isn’t absolutely true, however, that all humans in all circumstances should avoid peanuts. Same goes for morality. We can say that certain instances of suffering are objectively bad, regardless of subjective or cultural beliefs, without then claiming some absolute truth. Take your murder example: An absolutist would say that murder is always wrong, no matter what. A subjectivist or relativist would say that murder’s wrong only if a person or culture says it’s wrong. An objectivist would say that in most cases, murder is objectively wrong, although there may be instances where murder isn’t necessarily wrong; we must look at it case by case, but there is, in fact, an answer as to whether the instances are morally permissible. This is called value pluralism and it brings up a lot of questions about how we can measure right and wrong and whose opinion counts and so on. It opens up a bag of morality worms. But even though these things are complex and daunting, doesn’t mean they’re not true or worth exploring. I feel like a pluralistic, objectivist approach to ethics lends itself to the inherently complex subject matter. It would be nice if there were easy absolute truths in ethics, but the world appears to be far more interesting and enigmatic than that.