If your claims are all true, then perhaps it’s better for you to be depressed so that you can see the wonderful world more accurate…

I suspect that a moral realist, for instance, would look at an ethically-acting moral anti-realist and say "they don't realize the existence of moral truths, but clearly they still know them, because they act according to them", right?

I doubt it. Anti-realists usually produce an error theory that explains why the realist language is favored in a discourse, and a paraphrase that 'translates' it. Whatever knowledge is contained in a realist formulation, gets reinterpreted without loss of content. But interpretations may affect creative, connotational and motivational aspects. Nominalists about math, say, are less motivated to pursue certain types of knowledge than platonists who believe in one true answer to every 'valid' question, the two sides put different weights on various clues and heuristics, etc.

@Kaia Yes that's what I'm getting at. I guess it's an amazing fact then that belief doesn't preclude knowing.

@Conifold I guess I have the stakes roughly accurate then. Thank you. Makes for an interesting take on the typical pedagogy though, at least in my experience.

@DoubleKnot I'd note that in many studies, the concept of depressive realism has failed to replicate. And also... social-psych from the 80s to 2010 is really heavily impacted by the replication crisis--at least for me personally, I take"results" from that field with at least a good degree of skepticism.

The confusion comes from attempts to answer this question (realism-anti-realism) in absolute terms. There is no black and white. There is always a fraction for everything. According to Simulation Theory, preprogrammed "moral values" can slightly change based on the context of execution. There are no static constant "moral values", but dynamically calculated "moral values" are always in play.

@Kaia no surprise, error could be everywhere including the wonderful error theory to address the other ubiquitous mundane errors…

Hao Wang made an interesting comment about Gödel's discoveries. He wondered : If Gödel had not been a platonist, would he (psychologically) have been able to find his incompleteness result. (Perhaps analogous to people claiming that a belief in free will is needed to avoid fatalism, even if free will is nonsense.)

Yes... Let me look that up. Hao Wang is a pretty interesting guy - almost unknown as philosopher, I believe. -- It's based on Gödel's private communication (a long letter to Wang in 1967), quoted at length in "From Mathematics to Philosophy" (1974, page 8). This book contains Wang's musings on math and what he proposes as "substantial factualism" - a "respect for vague but general facts" as basis of philosophy. Really deserves much more attention. (Definitely a lot more depth then Wittgensteins philosophy of math imo.)

If you cannot find the book - I could quote the passage + letter verbatim in a partial answer - if you want. It could serve as a concrete illustration of @Conifolds comment above.

I’ve just realized my title may have been confusing. I replaced “certain knowledge” with “any knowledge” and reworded the rest because I don’t mean the knowledge has to been certain. Rather, is there a class of knowledge we here only a realist mindset can grasp it?

@mudskipper I guess if one has to be wrong, it is important to be wrong in the right way :-)

Are you asking about knowledge, or understanding or something else, please? Can you cite special properties making the Question more relevant to the realism vs anti-realism debate, or do the same principles apply for instance to Roman Catholicism and Protestantism; to republicanism or royalism; to climate-change believers or deniers? Are you not suggesting that having knowledge is not enough… understanding can come only from belief about that knowledge?

@RobbieGoodwin I think understanding is more subjective. I can understand logic in my own way that I doubt a realist does, but we both hold the same knowledge over logic (or do we…). I don’t know if belief plays a role, maybe it does. I’m just focused on realism and anti-realism (across any domain though). I feel I can’t cover all of that in my question. This is my second attempt at the question as the first was too much already.

Thanks and that would seem to side-step the point if I could make sense of 'I can understand logic in my own way that I doubt a realist does, but we both hold' Can you rephrase that, please? Either away again, are you not suggesting that having knowledge is not enough… understanding can come only from certain beliefs about that knowledge?

@RobbieGoodwin Let’s say I ace all my logic courses and I’m an anti-realist about propositions. I have all the knowledge as the realist who aces the same load. But do we understand logic the same? I don’t know, probably not. Is it because I believe in anti-realism our understandings might differ, or is it just because I’m just an anti-realist like an auto mechanic is not a marine mechanic? Each mechanic understands according to their toolset. I don’t want to make this too much about belief, but maybe it is somewhat. I haven’t peered that far.

That's much more relevant, useful and interesting than the OQ. Isn't 'Do we understand logic the same?' the wrong Question? Should it not be 'Were we taught the same logic?' I see 'Is it because I believe in anti-realism our understandings might differ, or is it just because I’m just an anti-realist…?' as at best drifting towards navel-gazing. Can you rescue it with a different phrasing?

@RobbieGoodwin Hmm I thought I rescued it with the mechanics bit right after. An auto mechanic and marine mechanic take the same class on engines and get the same grades. The auto mechanic understands the engine pedagogy as it relates to auto car engines, and the latter to watercraft engines. This is a way without belief, if we want to remove belief, which I’m not making central here. They were taught the same, like the logic students. Im assuming we can teach largely the same to different types of mechanics and different students who may be at different places at the realism/anti realism axis