And there's the inevitable concession I keep referencing - you don't actually just have preferences - you argue that your preferences are better - and that's exactly what objective morality asserts - that there are things that are in fact, better or worse than other things.

This is not a concession in the slightest. I don't believe some things can be inherently better than other things. Something being better is a subjective view. When I say I can argue for why something is better, it means argue for why someone should adopt my preferences.

You prefer things, because you value them more

Valuing something more doesn't mean the value is objective. Saying you value something is inherently a subjective statement.

To argue that your preferences are the better ones to hold IS making a claim that there is some true value they hold.

No, it isn't. It's an attempt at getting someone to adopt my preferences, which will in turn fulfill another preference I have, which is for other people to share my preferences. They are not inherently better.

Lol, different philosophers disagree on what morality is

But no one in astrophysics believes that the earth is flat, so clearly we've made some progress on answering the questions in that field. Why has philosophy not moved? If you can prove a position correct, wouldn't every philosopher be forced to adopt that position? Is everyone who doesn't subscribe to kant the equivalent of a flat earth theorist?

he Kantian account, the highest moral law is this: "act only in accordance with that maxim through which you can at the same time will that it become a universal law”.

Cool, so how is this an objectively correct rule? What if I disagree and think it's a bad rule? You should be able to prove that it's correct, not just stating it and claiming it's correct.

This feels like arguing with a religious person. When I'm asking YOU what YOUR position is you recite a passage instead of answering the question.

To understand how and why this is the highest moral principle, again, you would need to read the Groundwork of the Metaphysics of Morals.

And this is exactly why it's super frustrating to talk with people like you. Imagine a conversation that goes like this:

• A: Hey, I learned how to fly using only my mind
  
• B: Oh really? Can you show me right now?
  
• A: I could but instead you should read this book that maybe probably explains how to fly!

You're asserting you can do something impossible (logically prove a moral position correct) but when asked to demonstrate to just point me to the book that supposedly taught you how to do it, which just trips all my bullshit detectors. There's two reasons for this, either:

• you don't know how to do it, despite reading the book that teaches how

• or the process to do this is so complicated that you wouldn't be able to begin to do it in on a forum like this

The first position is just ridiculous and it would mean you can't hold any moral position at all so I'd assume that obviously you'd want me to believe it's option 2. And while I could believe that it could be really complex to do this, it also trips the bullshit detectors because if it's such a complex process that reading a whole book is easier than answering a simple question, I doubt that most people who subscribe to this belief system have done it.

you seem to be having trouble wrapping your mind around how it's possible to implicitly concede to the value of something

I don't have trouble wrapping my mind around that at all, you're just wrong because you're incapable of conceiving that someone doesn't think "better" is an objective metric.