TLDR: I enjoy thinking about philosophy, but I think it makes sense for me to focus on learning more about other domains (which are all debatably applied philosophy) to determine and achieve my goals.
I’m writing my impressions of five branches of philosophy. I spent about 100 hours reading and writing about ethics. And I spent less than 10 hours on each of the other topics I’ve covered. So I’m somewhere in between the philosopher AI and Socrates.
Metaphysics and Epistemology
Metaphysics tries to answer the question, "What is anything?" Anything means anything. “What is a table?”, “What does it mean for one thing to cause another thing?”, “What is time?” and “What is possible?” are all questions covered by metaphysics.
These questions can get deep. For example, should I define a table by its color, height, or weight? Is a table the same table if someone paints it? What makes two tables that look exactly the same different tables? If it’s because they’re in separate locations, how could you describe this difference if they’re equidistant from everything else? I don’t know.
Epistemology asks, “What does it mean to know anything?”
I can’t process how to analyze “What is anything?” and “What does it mean to know anything?” separately. How can I answer what anything is without knowing what it is?
And I’ve already asked myself what it means to know anything. I decided it was a semantic question.
Epistemology also seems to be the term used for other questions related to knowledge. For example, can we have knowledge? What makes knowledge justified? How can different types of knowledge be categorized? How can we acquire knowledge?
But all of these questions seem to depend on how knowledge and other terms (e.g., what is justified?) are defined. I don’t think that makes them worthless. As I’ve said, I think answering semantic questions are useful for communication.
Thanks to Bubblebath_expert on reddit for making this
While I doubt semantic questions can be 100% answered, new fields have been founded on top of assumptions (aka axioms or postulates) to help us measure our knowledge. Physics is an example of applied metaphysics. Probability is a form of applied epistemology.
Plus, “What is anything?” and “What does it mean to know anything?” are broad enough questions that many other branches of philosophy and other fields could be considered part of them. For example, I consider the most fundamental question in philosophy of science to be “What is science?” How could someone know that?
And does it matter?
Ethics is the study of what’s moral.
It was fulfilling for me to flesh out my moral opinions. As I said in that post, to me, it’s moral to maximize total happiness while minimizing happiness inequality for as many beings as possible. My other significant conclusion was that morality is subjective. That reduced my desire to read about ethics. When I started reading about ethics, I thought it would help me uncover objective moral truths.
So I’d only research and write about (normative) ethics to figure out exactly how I want to behave and spread my beliefs.
My most pertinent moral dilemmas are related to applying my existing moral beliefs (i.e., applied ethics) rather than not knowing what I feel is fundamentally moral. For example, reading about ethics helped me decide that I value the utility of animals. But that only helps me start to answer the question, "Should I go vegan again?" To answer that question, I’d want to look into 1) how much going vegan would help the environment, 2) how much pain factory-farmed animals feel, 3) how a vegan diet would affect my health, and 4) whether it’d cost more money to buy vegan food and if so, would it make more sense to donate that money to other causes instead? etc.
And how am I thinking in the first place?
Philosophy of Mind
The philosophy of many fields has been studied. There are Wikipedia pages for philosophy of music and philosophy of artificial intelligence. If I ask myself what something means, I feel like I’m essentially studying the philosophy of it. For example, I’d consider asking “What is a pandemic?” to be a question about the philosophy of pandemics.
These philosophy of X fields ask deep questions about a known subject matter. Applied philosophy of music is music.
But philosophy of mind seems to be different. There’s no common term for applied philosophy of mind.
What is the mind? Well, if I try to 100% define it, it’s a semantic question. But it seems to generally refer to the thing used to think. These thoughts can be anything from “Eureka!” to “I’m in pain.”
The significant question philosophy of mind asks is whether there’s more to be done to understand how we think than understand the physical properties of our brain. There are many theories that there are mental properties as fundamental as physical properties such as subatomic particles.
Panpsychism suggests these mental properties are within all physical things (i.e., matter). This would mean everything has some form of consciousness. (But not that they have thoughts remotely as complicated as human thoughts.)
Dualism suggests the mind is a distinct non-physical entity from the brain. Some forms of dualism take this further and imply that the mind could be separated from our bodies and last after someone dies. It’s hard for me to imagine how dualism would be true. It’s easier for me to imagine these mental properties inside matter, like in panpsychism.
And a materialist would think this is all nonsense and there are no mental properties to be discovered. They’d say the mind and the brain are the same thing, and applied philosophy of mind is neuroscience.
I understand the materialist position. The speculation about the mind sounds kind of like spiritual nonsense to me. But I’m open to the idea that there’s still a ton nobody’s learned about science. Fields have been spun out of philosophy in the past. Maybe scientific advances will lead to a new term for the study of “mind science.” But for now, it’s still considered philosophy.
Maybe because it’s currently sufficiently abstract and useless? Like logic?
I’d define logic as the study of language to determine correctness.  For example, a classic form of logic, propositional logic, would provide constructs to form a statement, such as if A and B are true, then A is true. The notation used to denote that statement would be A ∧ B → A.
If A and B are replaced with any true statement, the conclusion that A is true remains correct. For example, if Washington D.C is the capital of the United States and Ottawa is the capital of Canada, then Washington D.C is the capital of the United States.
However, that’s useless if the statement’s premise is invalid. I could’ve written that New York City is the capital of the United States.
So Is logic useful? I think so. If I’d thought about logic, I wouldn’t have said, “I don’t 100% know anything.” So I think it helps me more literally understand the meaning of my statements.
My impression is that logic has been far more useful when it’s been applied to develop programming languages. 
Why did I study philosophy? The first time I briefly did it (less than 10 hours from 2018-2020) was to learn about utilitarianism, which I was inclined to assume was correct. Then, realizing classical (total) utilitarianism would theoretically support a utility monster threw me into a loop. I decided I needed to find the fundamental moral truth. While I decided I believed morality was subjective, I still found studying ethics valuable. When I wrote My Morality, I got to the point where the “moral part of me” didn’t feel like a confused mess anymore.
I still thought studying other branches of philosophy could show me some universal fundamental truths. And the part of me that wants to feel intelligent was attracted to the sound of words like metaphysics and epistemology. But I didn’t find any fundamental truths. I didn’t learn anything that I felt was personally important to me, like my moral opinions, either.
I think reading about philosophy of mind let me learn a little bit about a potentially super-duper, important question. But it sounds super-duper, ridiculously hard to learn about the “mind.” If it even is more than the brain after all.
Learning about metaphysics and epistemology helped me appreciate the difficulty of clear communication. And thinking about logic helps me understand the preciseness of my language.
I’ve still only done a broad overview of philosophy. However, there’s a lot more to learn. Everything besides the most fundamental philosophical questions may be based on axioms (assumptions), but I’m willing to bet studying philosophy (i.e., what I’d study in a philosophy course that’s not applied philosophy) isn’t the best way to achieve my moral goals.
Something could come up that leads me to reconsider. But for now, I’m moving on.
(cross-posted from my blog: https://utilitymonster.substack.com/p/my-take-on-philosophy)
Based on googling, there seems to be an enormous amount of disagreement about how to categorize the branches of philosophy. So don’t take my division too seriously. I spent less than 15 minutes thinking about it.
To research metaphysics, I skimmed Metaphysics: A Very Short Introduction by Stephen Mumford.
Metaphysics: A Very Short Introduction pg 28-29
To research epistemology, I skimmed Introduction To Philosophy: Epistemology by Brian C. Barnett.
And these assumptions are ideally defined clearly enough that semantic debates don’t prevent the fields from achieving anything.
It’s not a direct leap from metaphysics to physics. Many assumptions in physics are based on the assumptions that are the foundations of math. There’s also the separate term applied physics. It’s used for physics research that seems to generally be considered more practical.
Per Wikipedia, the Kolmogorov axioms are the most common probability axioms. Cox’s theorem is an alternative to them. And since probability is a branch of math, I’m assuming it’s based on other mathematical axioms.
That’s based on skimming Philosophy of Science: Very Short Introduction by Samir Okasha.
I most closely read the following articles on ethics: 1) Ethics 2) Egoism 3) Hedonism 4) Consequentialism 5) Egalitarianism 6) Utilitarianism 7) Virtue Ethics 8) Moral Egalitarianism 9) Moral Anti-Realism Sequence #1: What is Moral Realism? 10) Moral Anti-Realism Sequence #2: Why Realists and Anti-Realists Disagree. I also looked at a lot of articles on the Stanford Encyclopedia of Philosophy and Wikipedia on similar subjects.
Ethics is sometimes categorized as part of axiology, the study of value. The other field I briefly studied (i.e., less than 15 minutes) that’s sometimes considered part of axiology is aesthetics which asks, “What is beautiful?” I lost interest in aesthetics quickly because I lean towards believing that what’s beautiful is subjective. I think nothing is objectively valuable.
As I’ve said, I’d spread my beliefs because that would make me happy, not because I think my morals are objectively correct.
I skimmed Introduction to Philosophy: Philosophy of Mind. I also found this podcast helpful.
There’s no exact definition of what makes a field a field. Apparently, psychology was considered part of philosophy until the mid-1800s. It seems unclear when the term physics became more common than natural philosophy. I’ve also seen vague claims that economics and linguistics spun out of philosophy. And arguably, everything is applied philosophy.
I skimmed Logic In Action.
Logic is also studied in other fields, such as math, linguistics, and computer science.
And quantum logic is applied to quantum computing.
I'd think of psychology as a more applied version of neuroscience and the "mind science" I don't think there's a name for.