Eliezer, this explanation finally puts it all together for me in terms of the "computation". I get it now, I think.

On the other hand, I have a question. Maybe this indicates that I don't truly get it; maybe it indicates that there's something you're not considering. In any case, I would appreciate your explanation, since I feel so close to understanding what you've been saying.

When I multiply 19 and 103, whether in my head, or using a pocket calculator, I get a certain result that I can check: In theory, I can gather a whole bunch of pebbles, lay them out in 103 rows of 19, and then count them individually. I don't have to rely on my calculator - be it internal or electronic.

When I compute morality, though, the only thing I have to examine is my calculator and a bunch of other ones. I would easily recognize that most calculators I come across will give the same answer to a moral question, at least to a limited number of decimal points. But I have no way of knowing whether those calculators are accurate representations of the world - that is, perhaps all of those calculators were created in a way that didn't reflect reality, and added ten to any result calculated.

If 90% of my calculators say 19 times 103 is equal to 1967, how do I determine that they are incorrect, without having the actual pebbles to count?