29 August 2015 9:45 PM (ethics | convincement)
Many people have beliefs that differ from mine. This is no surprise. Often, I think about what evidence would convince me that I'm wrong. This helps to organize my thoughts and make me understand why I think what I do, and if I wish to have accurate beliefs I should be able to explain the basis of my beliefs. Also, I might be wrong. Last month I was thinking about what evidence would make me change my mind on something, and I realized the evidence was actually against me.
Sometimes I will disagree with people not on a factual question, but on a course of action or preferred arrangement of the world. Often this can be resolved by appeal to factual questions, since we both have similar goals. Sometimes, the other person is using a set of norms alien to me that involves duties, rights, and culpability. There we come to an impasse, because all their arguments are predicated upon their norms.
The norm I use is, broadly speaking, consequentialist. Consequentialism is the belief that the morality of an act depends on its consequences. This is the textbook definition, though the emphasis and flavor are different than what I shall use later. I asked myself, then, what would convince me to stop believing that consequentialism is correct?
A tricky question, that, since I don't actually believe consequentialism to be true at all.
Are we not straying as through an infinite nothing?
No moral statements are true. This seems counterintuitive at first. When you contemplate murder, torture, there is just such an intense and obvious revulsion that seems primal and basic. People build institutions around moral norms. They speak about them, they reason from one duty to another. They try to reconcile opposing duties. By all social and linguistic evidence people treat moral statements as propositions that can be true or false and act as if they are true.
Intuitions are not a good guide to truth. At night, step out into the darkness. Taste the air. You and I and everyone else feel the world alive, filled with presence and purpose, working its own secret ways. We hear the wind whispering in a language we can almost comprehend. Everywhere we look we see shapes like eyes and faces staring back at us. Our intuitions tell us to believe in animism, but all our actual investigations tell us not to, and animism is a less dubious claim than moral realism.
Want more intuition? Spit into a small cup, as much as you conveniently can. Wait about thirty seconds. Now, drink it. Go ahead, it came out of your mouth. You swallow your own saliva all the time, you won't pick up anything from it. If you're like most people, you find the idea intensely revolting. There's no Universal Principle of Disgust.
We have a much better explanation for these strong intuitions that all people share: evolution. Evolution doesn't aim for accuracy, just survival. That's why our tripwire for animacy is set so low. That's why we have such high ‘yuck’ factors. It's also why we have the inconsistent tangled mishmash of moral intuitions that humans do. Humans are pack animals and have evolved a random set of biases and inhibitions and notions of things that are right and wrong to do and a propensity to adopt the norms of the pack they are in because preventing packs from being disrupted and falling apart improves reproductive fitness. Humans are not unique in showing morality-like behavior. Recent experiments show dogs and monkeys judging humans on the altruism and fairness of their actions.
Not only are there no phenomena explained well by moral realism, but there is no kind of thing that an objective moral norm could be. Moral realism is a much more metaphysically extravagant view than mathematical realism. Mathematical realism amounts to no more than adding a new domain of objects about which propositions can be made. It is dubious because these objects are often considered to be outside of space and time and there is no plausible way for people to gain knowledge of them.
We can imagine trying to create a moral norm ‘mathematically’. Construct a (very large) set of axioms describing humans and their behavior and invent a quantity associated with each human that varies over time as a function of past actions. Call it culpability. If you're a full-blooded Platonist, you can claim it's real and exists. Congratulations. It may easily prove that killing people and lying increase ‘culpability’, but there are two problems. First, there are lots of mathematical objects that are perfectly consistent and do not explain reality; we call them ‘theories of physics that happen not to be true’ when someone has gone to the trouble of testing them out to see if they do. Second, naming a quantity in your mathematical construct ‘culpability’ doesn't create an obligation any more than naming the components of hadrons ‘quarks’ makes them creamy and spreadable.
It is my contention that there is no possible object that could exist that would create a duty.
No one can construct for you the bridge upon which precisely you must cross the stream of life
 Formally, this is known as the Evolutionary Debunking Argument.
 This is often known as J. L. Mackie's Argument from Queerness. It's fairly safe to say that he didn't invent it. I and most other moral skeptics have thought up something of the sort independently, though perhaps not as well formalized as he.
 Yes, that means I think the constructs in category theory have a better claim on reality than does the moral wrongness of torturing innocent people to death, and yes, I am okay with that.
 That is, mathematical knowledge and reason seems disconnected from the real objects named in the propositions. The objects exist solely so that the propositions are not false by virtue of their subjects happening not to exist. This is a problem even in Max Tegmark's ultimate ensemble; mathematicians can reason about mathematical objects that exist only in other universe while having no knowledge about those other universes, so the other universe may as well not exist. This is why the Ultimate Ensemble really offers nothing that modal structuralism doesn't and happens to be a trivial consequence of combining it with modal realism.