That's not really true. The study of truth goes across many subfields, including metaphysics and logic as well. In fact most of the work today on truth is on its metaphysics.

For example, I wrote my PhD thesis on truth and I don't consider myself to have an AOS in epistemology whatsoever; I'm firmly in metaphysics.

I would recommend Jenkins' What Love Is: And What It Could Be, which is a book on the philosophy of polyamory by a polyamorous philosopher.

This is a pretty big question. If you're looking for something very intro level on truth, Blackburn's Truth is ok. A but higher level (like a philosophy undergrad course level) would be Wrenn's Truth, which I prefer. If you want a big anthology of primary readings you can't do better than The Nature of Truth: Classic and Contemporary Readings, 2nd ed.

ABSTRACT:

> Our interest is in the possibility of there being a philosophically interesting set of useful false beliefs where the utility in question is specifically epistemic. As we will see, it is hard to delineate plausible candidates in this regard, though several are promising at first blush. We begin with the kind of strictly false claims that are said to be often involved in good scientific practice, such as through the use of idealisations and fictions. The problem is that it is difficult to see that there would be any epistemic utility in believing such claims, as opposed, say, to merely accepting them. Next we turn to the challenge posed by epistemic situationism , which when embedded within a plausible form of virtue epistemology appears to show that sometimes purely situational factors can play a significant explanatory role in one’s cognitive success. But again it is hard to see how the role that these epistemically beneficial situational factors contribute can be cashed out in terms of epistemically useful false beliefs on the part of the subject. Finally, we turn to the Wittgensteinian conception of hinge commitments ,commitments that are held to be epistemically useful even if false. While the epistemic utility of these commitments is defended, it is argued that one cannot make sense of these commitments in terms of belief. Support is thus canvassed, albeit in a piecemeal fashion, for the thesis that the prospects for there being philosophically interesting cases of epistemically useful false belief are poor.

In Chapter 2 of the Groundwork Kant lays out the various formulations of the Categorical Imperative, explaining how they work and giving examples of their use. If you read one thing of Kant it should be that.

> He thought that there was this big list of moral codes [list of rules that gets progressively sussier]

This isn't true. There's only three or four formulations of the CI depending on your interpretation.

>He uses the example of someone with a family opening the door after getting a knock. Standing there is a psycho axe murderer who asks him where his family is. Now the question is, should he lie? Well I think most people would say yes.

Beside the point for Kant interpretation but why should I think the fact that most people would say you should do something as good evidence for doing it? People get moral judgments wrong all the time, especially when you introduce features that test their rational consistency.

>While lying is usually wrong, doing it to save your family is ultimately good. But Kant would disagree. He says that if you were to lie and say they're not home, the psycho axe murderer would disappointedly turn around and walk away, thinking about how he's an embarrassment to his psycho axe murderer ancestors when all of a sudden, he sees your family climbing out of the window. Turns out they overheard the conversation and decided to escape, but if the guy had just told him the truth that they were in fact home, they would've had a chance to escape. Now, I've been keeping a veneer of objectivity in this video so far, but I've gotta say this is one of the dumbest ideas in philosophy I've ever heard.

Kant definitely doesn't say anything like this, and you haven't even attempted an explanation of why Kant thinks lying is morally wrong. Even if you disagree with Kant's reasons for thinking lying is morally wrong, he never claims that the axe murderer will act in this way.

> I mean, leaving aside that he's totally taking for granted that the family would overhear the killer and try to escape through a window that's conveniently in his line of sight, you're tellin' me if a billion people were strapped to a conveyer belt being dragged to the pits of Hell, and you can stop it all by slapping a kitten, he'd be like 'nah bruh it's still fucked up like you can't justify slapping a kitten over anything durrr"

Kant famously doesn't think animals are owed anything and that the value of people is always superior to the value of things (e.g. cats), and thus he would never say this.

Given the above, I think you could really benefit from sitting down and reading Kant. More generally, if you find yourself saying something like "This extremely influential and well-respected philosopher is obviously wrong", the principle of charity would suggest you probably misunderstood them.

Your explanation of Kant is so far off I can't imagine you've ever read him, any Kantians or any reputable introductory ethics text.