Follow-up to: https://www.lesswrong.com/posts/PSichw8wqmbood6fj/this-territory-does-not-exist
Here's a simple and direct argument for my version of verificationism.
Note that the argument uses ontological terms that are meaningless on my views. It functions as a reductio - either one must accept the conclusion, or accept that some of the premises are meaningless, which amounts to the same thing.
Premise 1: The level IV multiverse is possible.
Premise 2: If the level IV multiverse is possible, then we cannot know that we are not in it.
Lemma 1: We cannot know that we are not in the level IV multiverse.
Premise 3: If we are in the level IV multiverse, then ontological claims about our world are meaningless, because we simultaneously exist in worlds where they are true and worlds where they are not true.
Lemma 2: If we can know that ontological claims are meaningful, then we can know we're not in the level IV multiverse.
Conclusion: We cannot know that ontological claims about our world are meaningful.
Edited to add two lemmas. Premises and conclusion unchanged.
>Everything you're thinking is compatible with a situation in which you're actually in a simulation hosted in some entirely alien reality (2 + 2 = 3, experience is meaningless, causes follow after effects, (True ^ True) = False, etc, which is being manipulated in extremely contrived ways which produce your exact current thought processes.
I disagree, and see no reason to agree. You have not fully specified this situation, and have offered no argument for why this situation is coherent. Being as this is obviously self-contradictory (at least the part about logic), why should I accept this?
>If you have an argument against this problem, I am especially interested in hearing it
The problem is that you're assuming that verificationism is false in arguing against it, which is impermissible. E.g. "maybe you're in an asylum" assumes that it's possible for an asylum to "exist" and for someone to be in it, both of which are meaningless under my worldview.
Same for any other way to cash out "it's all a delusion" - you need to stipulate unverifiable entities in order to even define delusion.
Now, this is distinct from the question of whether I should have 100% credence in claims such as 2+2=4 or "I am currently having an experience". I can have uncertainty as to such claims without allowing for them to be meaningfully false. I'm not 100% certain that verificationism is valid.
>It seems like the fact you can't tell between this situation and reality
What do you mean by "reality"? You keep using words that are meaningless under my worldview without bothering to define them.
>The real question of importance is, does operating on a framework which takes specific regular notice of the idea that naïve realism is technically a floating belief increase your productivity in the real world?
This isn't relevant to the truth of verificationism, though. My argument against realism is that it's not even coherent. If it makes your model prettier, go ahead and use it. You'll just run into trouble if you try doing e.g. quantum physics and insist on realism - you'll do things like assert there must be loopholes in Bell's theorem, and search for them and never find them.