> Sure, my point wasn't that the yuckiness of spinach and the purpose of life were equally important issues, but that on the view that oughts are simply matters of opinion, that my rejections of the claims "spinach is yucky" and "our purpose is to reproduce" are equally valid---I've simply disagreed with an opinion of yours. This is very different from me rejecting a claim like "The earth is round". And I think, with claims like the latter, it makes sense for a rational discussion to be had about whether or not such a claim is right. But with claims like "spinach is yucky", there's surely nothing to be discussed---I like spinach and you don't, end of story.

If you don't like spinach, I think it would be counterproductive to tell you that you do in fact like it or that you are wrong not to like spinach. I still think you are capable of liking it, so people could offer you suggestions as to how you can make it better. Feeling a meaning in life is exactly like that; you can't tell a depressed person that they're wrong. I think it's healthy for them to have a chance to express themselves though.

> But I think you sense that the purpose of life isn't this kind of claim; otherwise it wouldn't make sense to try to rationally discuss this claim.

I can't see how it's not perfectly fine to rationally discuss subjective claims; there is philosophy of art, for starters. Just because I think morals are subjective, doesn't mean I don't see the value in having compatible values or at least an understanding of why differences exist. If you look up 'ethical expressivism', it might make more sense.

> Maybe that an unconscious reproductive drive undergirds the desire to engage in such activities even if they are not immediately related to reproduction directly? OK - maybe so, but if all of human behavior is undergirded by a reproductive drive, "our clear purpose is to reproduce" doesn't actually tell us anything about what to do, since anything that we do would be distantly related to a reproductive drive, and we're back to square one.

You mentioned detachment from life, and I think curiosity is what makes us humans stand out. I think what we need for fulfilment is so simple that it's so hard for people full of curiosity to accept it. That's why I agree with the idea that a rigorous approach to truth (including truth you don't like) will bring you back to what matters.

You have an intuition that reproduction is far too simple a story. I think at the core all humans have some values hardwired, but we can't exist on that level because culture has become far too complicated. We can't reproduce without cultural sophistication, because societies are too big to not require cultural sophistication. Also, I think you're still partially mixing up short-term and long-term fulfilment. Drugs can make you feel really fulfilled short-term too. Dare I say it, activities that don't feed back to what matters are probably escapist and may even be parasitical. Societies are in trouble when they have a hard time drawing the line between what is constructive and what is parasitical.

> (Of course, that's all putting aside that that all says nothing about what our true, objective purpose really is.)

I can't see how 'objective purpose' is not an oxymoron. A hacker is someone who dismisses the notion of an objective purpose in a tool and repurposes it as they will. Purpose is always subject to a being's existence. You have an intuition behind the word 'purpose' that I do not seem to have, as if purposes can exist without any beings. Do you really believe that morals can exist without any beings?

> These things don't make beliefs about the shape of the earth or the relationship between the earth and the sun fashions in the sense that there's no truth of the matter. So too for morality.

You think morality is progressive like science/knowledge. I would say morality only seems to progress because it reflects science/knowledge. Morality is rooted in emotion. You can reason about it all you like, but there is a reason why the police carry guns around. Ultimately force is the decider of morality in modern society. People who do destructive things see them as being right. Even self-destructive things are seen as being right by those who commit them. You can think in terms of human rights, but the reality of morality is realpolitik. As far as I see it, we humans have failed for thousands of years to do what you seem to think we do.

Do you agree with every single word of the bill of human rights? Or do you see that it is also subject to interpretation?

> Maybe so, but I don't think scientific demonstrability is a necessary condition for something to be objectively true.

Sure I can see why you might think a priori truths are objectively true, but I don't think you can prove slavery is wrong a priori, because the premises will always require experience to accept them. You'll only be preaching to the choir, so to speak. Also, as I've previously stated, words like 'slave' vary a lot culturally, so I'm not sure you could even settle on a definition that people generally agree upon, setting aside the fact that you have to make the definition not too broad or too narrow.

Anyway, I still can't grasp what you mean by the word 'purpose'. It seems logocentric to me. I genuinely don't have the same intuition. I think the difference lies there, and so I don't think we're going to make sense of the differences with words. I understand how people could have a sense for moral realism, and I think some dogma is necessary for culture, so although we don't agree, I don't think it matters all that much.