Philosophy has never been helpful to me in anything career-ish.
Discussions related to free will and relativism have definitely changed some things about me personally, but it's too soon to tell if it's for the better.
Most parts of philosophy are worth studying. Though the LW sequences are amazing, it would be supremely arrogant and highly irrational to study only the sequences. I would recommend philosophy of science--get an introductory book and then read the most important works mentioned there. Epistemology and deductive logic are also very useful. Philosophy of mind is obviously very useful/important (though a bit harder IMO). And of course statistics.
The obvious answer is the mind-body problem, but since you asked I assume you don't consider that non-trivial. So I would add the problems of intentionality and qualia and the now-debunked issues associated with phrenology.
Also, it's important to note the difference between an "example of a non-trivial question which philosophy of mind addresses" and a problem in philosophy of mind which has been (mostly) solved. It could be easily argued that computationalism solves all of the problems above, at least as far as a pretty good number of philosophers are concerned, but these are still issues that are "addressed" in the sense that there is still philosophical literature being written about them.
I am currently studying a broad range of philosophical topics. I'm not prepared to suggest what is pragmatic to study, but rather how to study it pragmatically.
When I study a topic, I always have a goal in mind to direct my approach to the topic. This keeps me from getting bogged down and gives me a basis for choosing which leads to follow.
This is probably important in any field, but it appears to be especially important in philosophy. Philosophy is layered on itself with argument and counter argument. The current state of a topic depends greatly on its history. This also has helped me separate ancient and debunked ideas from modern ideas.
I have found that getting an overview helps to establish the main ideas and history of a topic. Then I am free to drill down in the areas that interest me most.
Different sources will focus on different aspects of a topic. Also, some authors write to look smart, and some write to communicate clearly. I don't let myself get bogged down in opaque articles, I can usually find easier to read sources if I look.
I have found there to be a lot of bunk in both classical and modern philosophy. Don't simply accept the conclusions you read about, challenge them and research the counter arguments to your points.
I'm not sure of the merit of studying philosophy as opposed to just personally thinking about philosophical ideas. For me, the most profound pragmatic benefit has been to deeply alter my own psychology as a result of examining ideas like free-will and morality. I had a lot of unexamined assumptions and strongly felt conventions and taboos that I managed to overcome through examining my own feelings in a philosophical way. This is very different from the kind of learnt understanding that can be obtained by reading other peoples ideas. I think it is very common for people to parrot philosophical statements without them actually altering a persons behaviour in any significant way. In particular, I find a lot of classic philosophy unsatisfying as it seems much less relevant in our society. I think this is particularly the case if you adopt a science is enough to explain everything and the brain is a computer perspective. I'd love to read some philosophy that gave me a new and distinct perspective that might alter my priorities, and thus my behaviour, but I have yet to read such material. The closest I've encountered would be status anxiety which helpfully reframes classic philosophical statements concerning status and value in a modern context. This really brought home the extent to which our values are culturally specific. This helped me to pursue my life with my own priorities, as well as giving me the perspective to enable me to examine what I actually value. In that sense I consider these philosophical ideas to be much more practically useful to determining my life than any piece of technical or theoretical understanding.
There is no such thing as philosophy-free science; there is only science whose philosophical baggage is taken on board without examination. — Daniel Dennett, Darwin's Dangerous Idea, 1995.
I'm not sure, but I would guess that most of the sequences on LW would count as philosophy in the broadest sense. All of philosophy is important if you ask me, since it deals with meaning, i.e. what is important.
The strength and value of philosophy lies in its freedom to pursue anything and fail.
The philosopher is free by virtue of his or her otherworldliness, by their capacity to fall into wells and appear silly. – Socrates
Who’s going to trace the unknown unknowns if not the philosophers?
Philosophy is a battle against the bewitchment of our intelligence by means of language. — Wittgenstein
If you want to be pragmatic, then you should learn about language to understand what is said in the first place:
…the language which functions as a medium for our grasping of thoughts is not natural language but a conceptual notation which results from a critical logical analysis of natural languages. — The linguistic turn and other misconceptions about analytic philosophy
What exactly do you mean by "a pragmatic perspective"?
In other words, how exactly is the question "Which parts of philosophy are worth studying from a pragmatic perspective?" different from just "Which parts of philosophy are worth studying?"?
Pragmatic has a different connotation in this particular instance I think.
Suppose one lives in a Marxist-Leninist dictatoriship. Studying the works of Marx and Lenin brings advantages beyond self-improvement or perhaps even pleasure as some appear to be arguing.
I found it interesting everyone missed this dimension of the question. In this light I would advise that one should also study some works Christian theologians (many are arguably in the realm of philosophy), Plato, Aristotel, Ibn Khaldun, Descartes, Rousseau, the British Empiricists, the great German philosophers, the foundations of Liberal and Utilitarian tought, a pinch of Marxist tought and a fistfull of Libertarianism.
Upon reading this I realized I simply proposed a abriged history of European philosophy. And thinking about it that is basically right.
The benefits: Primarily status signaling. Winning debates also becomes much easier once you have the templates of the basic argumetns there as well as heavy weight thinkers in each of those categories in its place.
Drawbacks: Cost in time and intelectual energy
I have a guess:
Let's say that studying philosophy is gratifying in and of itself. That would make the study of philosophy an intrinsic good. There might be some parts of philosophy whose study yields an instrumental good. These would be the "pragmatic" parts.
Pragmatism is worth studying from a pragmatic perspective. Materialism is worth studying from a materialist perspective. But postmodernism is not worth studying from a postmodernist perspective, so be careful to choose the right philosophies to begin with. Bwa ha ha.
Seriously though, the Less Wrong sequences are great. Eliezer started with math (Bayesianism) and science (cognitive science) and went ahead and pwned a huge swath of philosophy by staying within the well-established mathematical and cognitive frameworks. Philosophical subjects like 'aesthetics' are still difficult. (Schmidhuber's work on it is interesting though, and he approaches it from a super-simplified computer science perspective.) But old dilemmas like 'free will' and 'moral realism vs. antirealism' are dissolved.
People realize Bayesian epistemology was a philosophy long before Eliezer, right? It's a fairly large area of study in philosophy of science.
Er, I think so. The kind of person who reads Less Wrong is probably the kind of person who takes care to search Wikipedia or the SEP for words like 'Bayesianism' and get a feel for the relevant literature.
One of my favourite aspects of LW is knowing that, even if I forget to linkify an unusual or obscure name or reference, I will not get some Mr. McLazy replying with "What is X? Never heard of it".
Bayesianism is an epistemological position. Epistemology is a branch of philosophy. So, Eliezer did not pwn philosophy with "math".
Bayesianism is applied Bayesian probability theory. Bayesian probability theory is math. Which of those two propositions do you disagree with?
Frequentists accept all of the math behind Bayes Theorem, but are not Bayesians. The interpretation of probability is a philosophical subject, not something that is a straightforward consequence of the math.
Bayesianism is applied Bayesian probability theory.
Bayesianism is applied probability theory with additional epistemological premises. You can accept the former while rejecting the latter.
Note: I am out of my depth, and simply repeating (probably incorrectly) cached thoughts said by people smarter than me.
The interpretation of probability is a philosophical subject, not something that is a straightforward consequence of the math.
I was under the impression that there are sound decision theoretic and axiomatic justifications for the notion of subjective probability. Also, the sequences themselves provide pretty good justification. And if you want to quibble over the axioms of Cox's theorems, that seems to me squarely within the domain of mathematics.
Philosophy is the name given to the search for well-defined questions. The frequentist/Bayesian dilemma seems to me well-defined enough to be considered within the domain of mathematics. Epistemology just barely intersects with it.
I was under the impression that there are sound decision theoretic and axiomatic justifications for the notion of subjective probability. Also, the sequences themselves provide pretty good justification.
I agree that there are good arguments for Bayesianism. I disagree that most of the premises of those arguments are mathematical premises rather than epistemological (philosophical) premises.
I agree that there are epistemological problems in the foundations, but they seem to me mild enough to refute frequentism. I'm not really sure what frequentism is, though (other than the position that one should not speak of the probability of a hypothesis). Can you spell out what you think the coherent frequentist position is? I won't hold it against you or frequentism if you say no.
(If one just speaks of beliefs, maybe there is a coherent frequentist position that evades Cox's theorem, but frequentists hold that we make decisions [ETA: a metaphysical but not epistemological assumption]; and this should be enough to force probabilistic beliefs.)
I'm not really sure what frequentism is, though...Can you spell out what you think the coherent frequentist position is?
I'm not sure either, as I've confessed before, but here's how it seems to me: whereas Bayesians view beliefs as "thermometer readings" that go up and down as new information comes in, frequentists view beliefs as "certificates" that have to be "earned" through specific rituals, and are subject to periodic renewal.
Since (in view of results such as Cox's theorem) one can't really deny that probability theory is the appropriate mathematical model for belief if there is any appropriate model at all, it seems that what frequentists actually object to, deep down, is the idea of personal belief as the object of formalization. They are only comfortable with ("official") belief-formation as a social process. In their view (so I propose), you are only allowed to make probabilistic claims after you perform a well-defined experiment of some kind (specifically, of the kind in which relative frequencies of the events you're interested in can be observed).
Frequentists don't have a defined view of beliefs, they have a defined view of probability, namely that probability statements about events are statements about the limit of that event's frequency in an arbitrary number of trials. The Bayesian position is that probability can be understood as degree of belief. The Bayesian epistemological position is that all beliefs ought to be understood as probability statements. There is no Frequentist epistemology, a frequentist could hold any epistemology they wanted more or less.
I understand that this is the standard story, but don't find it satisfactory; hence was presenting my own "deeper" explanation (which I still regard as tentative).
After all, based only on what you've said, a frequentist could also be a Bayesian! This doesn't seem right, or at least doesn't seem to account for the fact that there seems to be a controversy between "frequentists" on the one hand, and "Bayesians" on the other.
I don't see how a frequentist could Bayesian, to hold a Bayesian epistemology one would also have to adhere to a Bayesian theory of probability. Since frequentists don't hold such a theory that can not hold Bayesian epistemology.
As per my original comment, someone could agree that probabilities represent beliefs but also hold that the content of ("legitimate") beliefs consists only of statements about frequencies. This would allow them to simultaneously hold a frequentist interpretation of probability and a Bayesian epistemology. (As you said, "There is no Frequentist epistemology, a frequentist could hold any epistemology they wanted more or less.")
I'm not a Frequentist (so I won't bother writing up a justification for the position), but non-Bayesians like R. A. Fisher, Jerzy Neyman, and Egon Pearson didn't just dogmatically refuse to accept the conclusion of a valid mathematical argument. They denied the truth of Bayesianism's epistemological premises (note: I disagree with their judgment in this case). Not one of them denied that Baye's Rule could be derived from the very definition of conditional probability (which is a straightforward consequence of the mathematics).
My comment was intended to point out that it takes more than standard probability theory and deduction to get you to Bayesianism. Additional premises (from outside of mathematics) must be present (at least implicitly).
Not one of them denied that Baye's Rule could be derived from the very definition of conditional probability (which is a straightforward consequence of the mathematics).
That's a reasonable response to Will's first two comments, but [ETA: not] as a response to his third comment, mentioning Cox's theorem, or my comment, mentioning decision theory. I don't blame you for not knowing whether they had a coherent system of beliefs, but I do blame you for this non sequitur.
ETA: maybe that would be reasonable if you just substituted Cox for Bayes, but only if these frequentists explicitly rejected their contemporary Cox, rather than just ignored him.
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