Some concepts are like Newton's Gravity, others are like... Luminiferous Aether?

One big difference between the theories is that Newton's theory of gravity was a fully mathematically worked out theory, whereas Luminiferous Aether was little more than a name for "the medium light waves traveled through".

Personally, I don't trust the concept of values. It's already so complex and fragile, I'm afraid it doesn't actually exist.

Depends on your definition of "exist", of course, but values certainly do exist in human society. Unlike with the aether, one can use the model of values to make testable predictions, and these predictions are confirmed more often than not. People who value integrity are less likely to lie and cheat, people who value knowledge are more likely to engage in research, etc.

The "more aethereal" concepts are those with little or no predictive power, such as Free Will, God and Many Worlds. Some of them still might turn out to be "right" if someone comes along and comes up with good definitions and clear predictions.

Apologies for having to ask for a clarification of values

Taboos would return different things for:

• personal values (or desires)
• universal values
• selfish values
• societal values
• object of value
• economic value by scarcity/demand (gold is worth more than nitrogen)

I am not sure which one you mean.

Good (not only Friendly, but useful to full extent) AI would understand the intention, hence answer that luminous aether is not a valid way of explaining behavior of light.

People invented the aether because all waves we see with our eyes need a medium. This is a very sound intuition, and in fact some people maintain that we can view spacetime itself as a type of medium for propagation of waves physicists study. In some sense the aether is "wrong," but in another sense, the approach behind it is right -- you use intuition with the familiar to guide your search and comprehension of weird stuff Nature throws at you.

Under theories like loop quantum gravity, doesn't some "fabric of spacetime" exist? I would call that a refinement of the idea of the ether. It has odd properties in order to allow relativity, but it hasn't been ruled out.

I wouldn't call luminiferous aether just plain wrong. Asking what it's made from doesn't make a lot of sense, but saying that that means it doesn't exist would be like saying electrons don't exist because they don't have a volume.

Personally, I don't trust the concept of values. It's already so complex and fragile, I'm afraid it doesn't actually exist.

It's something of a simplification. People are not ideal utility-maximizers. But they're close enough that it works well.

I'm afraid it doesn't actually exist

If a concept is held important by a large number of people, then it exists, regardless whether you personally believe in it or not. You can't compare concepts (or ways of thoughts, philosophies, etc.) to scientific theories, because a scientific theory doesn't become true because of how many people believe in it, but a social value does become true due to people believing in it or accepting it.