Perhaps this is not central to the post, but I have always found that bit from Pratchett to be unbelievably inane. Truly, it grinds my gears to see it quoted, in wise tones, as if it expresses some profound truth; and doubly so, to see it quoted on Less Wrong.

Consider the following substitution:

Take the universe and grind it down to the finest powder and sieve it through the finest sieve and then show me one atom of apples, one molecule of chairs.

Right? There aren’t any chair molecules, are there? You won’t find apples on the Periodic Table, will you? So what? Do chairs and apples not exist? Are they somehow not real, or less real than… well, than what…? Hydrogen? Methane? Should we adjust our attitude toward apples, or chairs, or paintings, or tigers, on the basis of this insight? What, actually, is to be concluded from this?

Anyway, this is old news. The point, if you like, is that of course ‘physics’ ‘contains’ ethics, and improvements in ethics; these things are facts about people, and the goings-on in people’s brains—which are (dualistic views aside) very much “contained in physics”. Of course, you could argue otherwise^[1], but you must do it without recourse to any such “greedy-reductionist”, “grind down the universe” arguments…

Western philosophy has no place for empiricism.

This seems a funny claim to make when there's an entire movement in Western philosophy (the British Empiricists) dedicated to empiricism.

As with much philosophizing, I agree with your diagnosis of the problem, but the solution seems dubious.

ultimate reality can be experienced

You see this claim all the time (e.g. Ken Wilber) but I have yet to see a shred of evidence for it. Given how the brain works, there seems to be no pathway to experience ultimate reality directly.

Bear in mind also the claim

the ultimate reality is the source of all existence

So we are supposed to be able to directly apprehend the source of all existence. The fact that many people experience similar feelings/insights/beliefs is weak evidence for the claim. Not much stronger than the common feeling among each and every new generation that they are the most virtuous and ethical of all generations. (As an aside, which usually comes with the feeling that they are the first to discover the wonders of sex and drugs/alcohol).

On the question of enlightenment this is a very overloaded term.

One use of the term that I found useful and other rationalists might is "The Finders" by Jeffery A Martin. This is a practical and useful version of enlightenment with very little mystification and few grandiose claims.

I was with you until "But there is a way to observe ethics in absolute terms. It is called "mysticism"" I have no idea what you mean there.

Have you ever noticed how Abraham, Jesus, Mohammad, Siddhartha and Ryokan all had a habit of going alone into the wilderness for several days at a time? Then they came back and made ethical pronouncements and people listened to them?

And how much similarity is there between the ethical pronouncements? Should you sacrifice your son to a hallucinated god, turn the other cheek, slay the unbelievers and rape their women, observe your thoughts until you conclude that nothing is real, or...?

So far, I find it plausible that going away from other people for several days is good to focus on developing your own philosophy. These days, you should probably also turn off the social networks. But is this walk less random?

I enjoyed and agreed with the first part of this article: I think the analogy of the random walk is an interesting way to think about progress in ethics. The section addressing moral relativism does raise a few questions, though.

Ethics is fundamentally subjective, but not relative.

Could you clarify what you meant by this? What is the difference between the terms, in context?

The Snowmass example has a few problems. To begin, religion =/= ethics. None of the Points of Agreement involve ethics in a meaningful way and they're all vague, involving meaningless terms like "ultimate reality." They're essentially religious Barnum statements.

Finally, how can contemplation in the wilderness be an experiment in observing anything but individual human psychology? I would be more convinced by an experimental attempt at optimizing religion/ethics if it involved, for example, looking at how prevalence of certain ethical/religious beliefs in communities correlates with objective, measurable values such as happiness or wealth. Empiricism involves analyzing experimental results against a current model, not just other experiments.

What does it mean for an ethical system to get “better”? Physics contains no such thing.

You say that as though there is no other possible basis to make an objective judgement. Naturalists tend to reject the idea of a separate ontological domain of ethical value, whoch is fair enough. but nihilism is too hasty a conclusion. There is also the domain of human cultural constructs, which is neither derivable from physics, nor ontologically non-physical.[*]

Norms about how well things function, how well they do their job, are objective enough, yet are not rooted in physics. There are norms about how to play chess well, although chess is clearly a human construct. There are norms about how to play run a economy , although money is clearly a human construct.

To judge the quality of an ethical system you must do so through your own ethical system

Ethical philosophy itself is an attempt to judge ethics by norms that are not ethical, such as rational norms. (Or mathematical ones in the case of "torture vs. dust specs").

The assumption that ethics has a function, that it is part of the "operating system" of society allows us to make judgements about better and worse systems of ethics, where "better" and "worse" are cashed out as fulfilling a function well or badly, and are not therefore circular appeals to the ethical sense of better and worse.

A universal standard of ethics must have practical utility in every society at every point in history.

I suppose so, but why would you want one? In order to justify moral progress, you need an objective standard of ethics, not a universal one.

Minimally, an objective truth is not a subjective truth, that is to say, it is not mind-dependent. Lack of mind dependence does not imply that objective truth needs to be the same everywhere, which is to say it does not imply universalism. Truths that are objective but not universal would be truths that vary with objective circumstances: that does not entail subjectivity, because subjectivity is mind dependence.

I like to use the analogy of big G and little g in physics. Big G is a universal constant, little g is the local acceleration due to gravity, and will vary from planet to planet (and, in a fine-grained way, at different points on the earths surface). But little g is perfectly objective, for all its lack of universality.

To give some examples that are actually about morality and how it is contextual:

• A food-scarce society will develop rules about who can eat how much of which kind of food.

• A society without birth control and close to Malthusian limits will develop restrictions on sexual behaviour, in order to prevent people being born who are doomed to starve, whereas a society with birth control can afford to be more liberal.

[* from Vaniver's review of Hariri's Sapiens]

But, of course, those modern institutions (as well as the ‘primitive’ ones) function. One division Harari discusses that I found useful was objective, subjective, and inter-subjective:

An objective phenomenon exists independently of human consciousness and human beliefs. … [Radioactivity is his example.]

The subjective is something that exists depending on the consciousness and beliefs of a single individual. … [A child’s imaginary friend is his example.]

The inter-subjective is something that exists within the communication network linking the subjective consciousness of many individuals. If a single individual changes his or her beliefs, or even dies, it is of little importance. However, if most individuals in the network die or change their beliefs, the inter-subjective phenomenon will mutate or disappear. …

Many of history’s most important drivers are inter-subjective: law, money, gods, nations.

That last list looks familiar. Gods and prices are not features of the wavefunction of the physical universe—they’re features of communication networks, or cultures. The creation of a third, explicitly defined category (phrases that mean similar things are “social construct” and “myth,” at least when used non-pejoratively) solves the epistemic crisis of realizing that many, if not most, of the interesting things in life are neither objective nor subjective. The rules of association football are not objective natural laws baked into the universe before there was time, but neither can they be changed by a single person deciding to play differently. (Many authors fall headlong into this epistemic crisis, and Harari every now and then seems to have his presentation, if not his arguments, tripped up by it. But on the whole he manages it well.)

Does this mean ethics is fundamentally relative?

No

Ethics is fundamentally subjective, but not relative.

You cannot "judge" an ethical system objectively. But you can observe it objectively and you can measure it objectively.

Yes, but that doesn't help. Suppose you want to objectively measure old testement biblical law.

You grab a bunch of people, force them to live under those laws, and observe the results. 

You find that people living under these laws aren't that happy, spend lots of time preying, and don't make many paperclips. It is only your own sense of ethics that focusses on the average happiness, not the paperclip production.

Ethics is shaped by cultural evolution, within the mostly fixed framework created by biological evolution.

This does not imply any kind of ethical progress. Our notion of current ethics being better than past ethics could still be due to us drawing the target around ourselves. Looking back at our ancestors, we see animals evolving to become more human-like.

It is possible to have something like ethical progress if you have some notion of ethics that depends on physical or logical statements about which you are uncertain.

I really enjoyed this, though I'm not sure I agree with your opening premise. It seems like an individual can subjectively improve their ethics over time, and through empiricism, so can a society. 

That said, I suspect an unspoken aspect to your argument is that we have already randomly walked around, if not precisely on, the optimal human ethic. In this way, there can be no ethical progress. It's just a matter of getting a critical mass of humanity to zero in on that location.