I’ve talked before about why we shouldn’t assume that moral rules will be universally applicable, or universally agreed upon: http://fensel.net/2012/08/26/why-do-we-assume-that-morality-would-be-universal/
In particular, I want to refer to the claim that morality would be universally agreed upon. Utilitarians argue that all people should act to maximize aggregate happiness; Kantians argue that all people should act in accordance with the categorical imperative. These theories, if fully convincing, would define one specific set of actions as “morally right”, and another specific set of actions as “morally wrong”. Each person knows the same moral facts and lives by the same moral rules.
Under objective theories, any moral claim, structured as either “X is morally right” or “X is morally wrong”, would have a definitive truth value. Moral “truths” would be objective facts, that a person can be mistaken in not knowing (it is possible for a person to say “X is morally right” and be mistaken).
Objectivity is commonly thought to be necessary for people to have mistaken moral beliefs. A non-objective theory cannot claim “this person’s moral beliefs are wrong”, since there are no objective moral facts to differentiate correct moral beliefs from incorrect moral beliefs. For example, cultural relativism cannot claim that a culture’s ethics are immoral, since that claim would be reduced to “culture X’s ethics is not in line with culture X’s ethics”. If relativism exists on an individual level, then what is morally right for each person is what each person thinks is morally right. No one can be wrong or have false moral beliefs, since everyone has a correct idea, by definition, about what is morally right for themselves.
This commonly held distinction (between objective theories and non-objective theories) leaves you with two possible options for morality:
1. There are objective moral facts, and it is possible for a person to be mistaken on the truth of a moral statement.
2. There are no objective moral facts, and it is not possible for a (person/culture/world) to be mistaken on the truth of a moral statement.
The point I want to bring up, against this distinction, is the possibility that we can reasonably disagree on what is morally right. I find this claim intuitively plausible, but it directly contradicts the definitive truth value of objective moral theories (since every moral statement has a definitive truth value). If there are objective moral facts, we could only reasonably disagree on the basis of ignorance (if one or more people were unaware of which moral facts were true). But any disagreement could, at least theoretically, be resolved by a reference to what is actually morally right.
My claim seemingly leaves me with possibility #2, making most moral disagreements meaningless. If a subjective source of moral rules (individual people, cultures, etc.) disagrees with what I think is morally right, our disagreement can only amount to a difference of taste. Neither of us would be able to refer to objective moral facts to prove the other’s beliefs are false, or wrong.
The problem is that I still think we can correctly say that some moral beliefs are wrong. If someone murders another person in cold blood, I feel comfortable claiming that their action is wrong, and I would still be convinced even if the murderer told me that he thought the action was morally right. I wouldn’t be satisfied with the conclusion “we have different moral tastes”, I would want to claim that his view is wrong, and mine is right.
The objective distinction claims that the truth of “there are no objective moral facts” and “there can be mistaken moral beliefs” are incompatible (to be clear/valid, it is compatible with “no objective moral facts” to claim that people can be mistaken on what morality is, in the sense that they do not know what the culture says morality is, or what others say morality is. But it is not compatible to claim that what people think is morality is wrong). It seems intuitive to believe that these claims are incompatible. But, consider the two claims I believe: “we can reasonably disagree on some moral beliefs” and “some moral beliefs are wrong”. These don’t seem incompatible with one another, at least initially. However, “we can reasonably disagree on some moral beliefs” is incompatible with “all moral facts are objective”, and “some moral beliefs are wrong” is incompatible with “there are no objective moral facts”. If either “moral facts are objective” or “there are no objective moral facts” is true, then it is impossible for both “we can reasonably disagree on some moral beliefs” and “some moral beliefs are wrong” to be true at the same time.
In order to maintain my beliefs that both “we can reasonably disagree on some moral beliefs” and “some moral beliefs are wrong” are true, I’d need a coherent sense of moral facts, such that neither “all moral facts are objective” or “there are no objective moral facts” are true. The only possibility for this is if there are some moral facts, and also some moral statements that do not have a truth value.
This consequence of my intuitions is unappealing, but I want to offer a way that it can be understood. Currently, I understand morality as a system of rules we derive from a common premise “human beings have value”. Moral facts are statements that can be validly derived from the premise “human beings have value”, such as “killing human beings is contrary to value” and “intentionally causing others harms is contrary to value”. In this sense, there are some moral facts-killing human beings is immoral (I am defining immoral as “contrary to value”).
There are also statements that cannot be validly derived from the premise “human beings have value” alone, but could if another premise was used, such as “animals have value”. From these statements, it would be valid to derive “intentionally causing harm to people or animals is contrary to value”. However, it is not possible to derive the premise “animals have value” from “human beings have value”. You cannot show the truth of “intentionally causing harm to animals is contrary to value” to a person who only accepts the premise “human beings have value”, but rejects the premise “animals have value”.
This is how I understand reasonable disagreement on morality. The statement “it is wrong to kill animals for food” could be derived from the combined premises “animals have value” and “humans have value”, but not from “humans have value” alone. Two people could disagree on whether or not it is wrong to kill animals for food, and both could have reasonable justifications for their position (as they start from different premises). This is how some moral statements can have no truth value-both positions can be reasonably derived from a position (a set of premises) that can be correctly called “morality”, since they include the premise “humans have value”. So both positions are reasonably derived from a morally acceptable viewpoint-yet they contradict one another.
Under this conception, it is possible for there to be some objective moral facts and some moral statements that have no truth value. Killing is wrong, because there is no morally acceptable viewpoints that the statement “murder is consistent with value” can be derived from. Killing animals can be reasonably disagreed upon, since there are morally acceptable viewpoints that both statements “killing animals is wrong” and “killing animals is permissible” can be derived from. (Important note: I am defining “morally acceptable viewpoint” as one that contains “human beings have value”, since that is what I think is necessary for morality/moral motives. If this assumption itself needs to be justified, and it is coherent to wonder whether or not human morality needs to value human beings, then my viewpoint is likely wrong. I am reasonably comfortable assuming that this is not the case, as I cannot understand what a human morality would be like if it didn’t value human beings)
Hopefully this is somewhat clear. This is how I currently understand morality, and I like maintaining the ideas that we can 1. reasonably disagree on some moral statements, and 2. some moral statements cannot be disagreed on. This theory is one way to understand how it is possible, and (combined with a lot of Korsgaard’s theory) it offers a good way to understand morality in general.
