In “Surely you can’t be serious” I wrote that “The evil of the cannibal seeking to eat Jim is, to put it bluntly, a metaphysically necessary truth.”
Brenda responded: “Well, that is a claim. One you have not proved must be true. I don’t see how you can ‘prove’ that cannibalism is necessarily wrong the way that you can prove an equation of arithmetic is true or false.”
Why the reference to arithmetic? Because I wrote of my incredulity toward certain postmodern deconstructionists for whom “the truth value of 7+5=12 is contingently determined by a community of language users.” Clearly there are facts that are not only objective (their truth value obtains irrespective of whether any language user recognizes them as true), but also are necessarily true (‘7+5=12’ could not have been false).
How about we consider another proposition:
“Nothing can be red and green all over.”
When we reflect on this proposition, we can see that, like 7+5=12, it also must be true. It cannot be the case that any object could be completely red and also completely green at the same time. Do we have a clear account of how we know this? Is such an account necessary before we can know it? Of course not. We grasp it and can see that it is true. If that is not proof enough for Brenda, well then I guess we’ll have to agree to disagree on that one.
And so it is for moral facts. Here is a grisly equivalent to our red/green proposition:
“The Hutu men who sodomized young Tutsi girls with sticks and carved out their genitals with butcher knives engaged in acts which are necessarily evil irrespective of the opinions of any or all human beings on the matter.”
Thus, even if those Hutu genocidaires had managed to take over the world and convince the rest of us of the righteousness of their despicable actions, those actions would still have been despicable:
“The Hutu men who sodomized young Tutsi girls with sticks and carved out their genitals with butcher knives engaged in acts which are necessarily evil irrespective of the opinions of any or all human beings on the matter.”
“Nothing can be red and green all over.”
The necessary truth of both of these propositions is, I would submit, readily apparent. If somebody insists that the necessary truth of one or more of these isn’t obvious for them, if they retort that they still want a “proof”, well then there’s not much more I can do. Whether it be the skeptic who doubts the existence of the external world, other minds, logic or morality, we may not be able to persuade them, but that hardly means we should take their doubts seriously.
