In doing my rounds in various forums debating moral relativists, moral non-cognitivists and moral subjectivists, I often come across an argument, that as far as I know is not usually endorsed by philosophers and ethicists. For example, A.J. Ayer who developed one of the earliest forms of non-cognitivism (there are no moral statements that are true or false) used the argument from relativity (better stated later by Mackie) and a version Moore's Open Question Argument in support of his non-cognitivist emotivism but rejected this argument, what I am calling here "the argument from lack of agreement". Nonetheless this is a popular argument. I want to investigate this here as to whether this is a fallacy.
It has many a variations but the underlying form here is "you will never get everyone to agree to a moral code therefore morality is subjective, non-cognitive and/or relative"(depending on the opponent, they could be arguing for any one or any combination of these) . Usually when pressed for why agreement is necessary one gets a typical statement like (this one, as it happens, from an Ayer inspired non-cognitivist ) " all that it takes to falsify such a claim is the presentation of just one person who sincerely holds a dissenting value". However surely it is likely that for just about every position on every issue on the planet there will be at least one dissenting voice and there is no reason for this to be sufficient to falsify that position. If this argument is sound and valid then there are no correct positions on anything period! It appears too broad and so lacks sufficient specificity to be used in ethics or, indeed, anywhere else. It looks like a tool of a universal sceptic and not the basis for exploring relevant doubts reasonably. Is there anything special about ethics that makes it applicable here?
Typically when pressed, anything else that is brought to bear to support this conclusion - e.g. saying "there is no agreement is possible because there is no objective fact of the matter" - appears to be question begging. For example, saying something like that there is no "objective fact of the matter" cannot be used in support of the validity of this argument structure, since this argument when applied in ethics at least, is a means to conclude that there is no "objective fact of the matter". To assume what one is trying to conclude is circular reasoning. There seems to be an assumption behind this argument, namely that, pursuing this example, if there were an "objective fact of the matter", then everyone could agree to it. As already indicated this is looks like a questionable assumption.
Well is there empirical evidence to support this assumption? As anyone with the slightest honest familiarity with science knows that evolution is a fact, yet many people have creationist like views. Does this falsify evolution? No. (And if it is not a fallacy, it clearly falsifies creationism too!) On the the other hand, Pascal Boyer, in "Religion Explained" provides a number of examples of where an anthropologist questions a community's supernatural belief in, say, witches, to which the response is incomprehension, they cannot even make sense of questioning the existence of such beings, it is so ingrained into the fabric of their culture's belief system. So there is significant contradictory empirical evidence against this assumption.
It seems to make no difference as to whether there is actually an objective fact of the matter as to whether there will be 100% agreement for or against that position. This argument is insufficient in and of itself to draw any such conclusion about whether a claimed fact of the matter is true or false nor whether there are indeed any facts of the matter at all in question.
Note that the above is not to refute a Pierce type approach to truth - which is about more than mere agreement - nor that lack of agreement can be used as evidence in support of a (better) argument. Still looking at this in isolation reveals deep problems in this argument.
Well it is a fallacy? Well, since I am an a dissenting voice in the validity of this argument then on its own terms it is false! Indeed, on its own terms, I do not even need to give an argument as to why I disagreed with it, I just need to disagree, however I do like to provide an argument to support my conclusions. It is self-refuting and therefore a fallacy.