Moral Realism and the Burden of Proof

by Ben Ryding

We begin as cognitivists and realists about ethics. … Moral Realism should be our meta ethical starting point, and we should give it up only if it does involve unacceptable metaphysical and epistemological commitments.

-David Brink

[Error theory] goes against assumptions ingrained in our thought and built into some of the ways in which language is used, since it conflicts with what is sometimes called common sense, it needs very solid support.

-John Mackie

It is not clear to me why philosophers think that the moral realist does not bear the burden of proof with respect to the existence of moral properties.  It is true, as Mackie points out, that moral anti-realism goes against our sensibilities and intuitions, but why should our intuition provide sufficient evidence for any sort of claim?

If someone asserts the existence of some entity, even if I find the existence of such an entity pleasing to my sensibilities, I would still like to see some sort of evidence for the existence of the entity in question. This discussion closely parallels arguments in philosophy of religion about the existence of God.  In that field, there are many attempts to prove the existence of God, either through deductive arguments, or more inductive evidential cases (a la Richard Swinburne).  But many arguments for the existence of God indeed rely on our intuition or seemingly innate sense for the divine.  There are approximately zero atheists who find this sort of argument compelling, however, and for good reason – our intuition and common sense about reality often fail us.  It is why we have the scientific method; why we demand rigor in our philosophical endeavors; and why we generally attempt to find reason and evidence behind our beliefs whenever possible.

I see no reason why morality should not be subject to the same scrutiny.  Where is the evidence for the existence of moral properties?  What sort of substance could moral properties consist of, especially if we are not to invoke the supernatural? Eventually I want to outline Mackie’s and Joyce’s work on error theory and establish a sort of agnostic error theory view on morality. Somewhere in between I’d also like to discuss how this all relates back to my posts on the problem of hell.