I haven't really been reading this post, but this is a problem I've thought
about a lot. It seems like anything in the realm of "is" is a real fact
about reality, with physical manifestations which can be measured and
verified. From more basic facts, we can use rational methods to derive more
complicated facts. On the "ought" side, there is no physical manifestation
of moral facts. If it is perfectly moral to kill innocent people, every
quark and lepton will still be in the same place and have the same charge as
it would in a world where it is immoral to kill innocent people (aside: this
is kind of similar to the problem of consciousness). I guess moral facts are
"virtual facts" in a certain way. I realized the other day, that in the same
way of real facts, these "virtual facts" can be reasoned about the same way:
start with basic moral premises, and use rational methods to arrive at more
complicated facts. Suppose it is immoral to kill a living being, and suppose
than an animal is a living being, it would follow logically that it was
immoral to kill an animal. The difference in "is" versus "ought" then,
reaches down to the premises. I'm not sure if "discovereing" underlying
moral premises present a special problem apart from discovering underlying
physical premises.
Incidentally, people often try to explain the basis of moral facts by
appealing to evolutionary principals: traits such as killing innocent people
for fun and without guilt were weeded out because this trait is detrimental
to survival. This line of argumentation misses the point. It may be (and
most likely is) the case that certain moral facts are hard-coded in our
brains because they give us survival advtantage, but this is a completely
different issue from whether these facts are objectively true or not.
Believing something can give you a survival advantage even when such beliefs
are false.
I'm reviewing this and finding things which I'm not sure I mean to say. It's
a very complicated issue.