In response to Assessing oneself
Comment author: ShardPhoenix 27 September 2014 08:40:10AM *  15 points [-]

I went a similar path (doing physics but not really excelling at it) and ended up a programmer. I'm pretty happy with programming overall. Note that in real-world applications, most of the effort goes into the engineering-like side of making sure your code is clean and maintainable, rather than the comp-sci-like side of having clever data structures and algorithms. It certainly doesn't feel "too easy" most days, though it can sometimes be frustrating when you end up spending time struggling with tools rather than what you're really trying to do.

Comment author: polymer 30 September 2014 01:28:00AM 1 point [-]

Perhaps I should've said, hard in the wrong ways. The long term goal for a good professional programmer seems to be understanding what the client wants. Some math is needed to understand the tools, so you can give some context for options. But I spend most of my creative energy making sure my programs do what I want them to do, and that is really hard when each language has it's own prejudice motivating its design.

I seriously considered looking into real time high risk software applications. But I just decided that instead of learning new languages until I ran out of youth, it'd be more fun learning general relativity, or even measure theory. The ideas in those subjects will probably hold out a lot longer then python.

In response to comment by polymer on Assessing oneself
Comment author: gjm 26 September 2014 10:06:50PM 19 points [-]

A few disorganized remarks that may or may not be any help:

  • Different people are good at different things. In particular, the algebra/analysis dichotomy is a pretty standard one and if you're good at analysis and not so good at algebra, it probably matters how good you are at what you're best at.
  • It seems like simply not being fast enough could be largely irrelevant (if it's really just a matter of speed; the limiting factor in doing mathematical research is unlikely to be how fast you can do practice-test-level questions) or quite important (if what it really means is that you didn't understand the material well and therefore had to flounder about when someone with a better grasp would have headed straight for the solution). You may or may not be able to judge which.
  • Motivation is really really important, perhaps more important than talent once the talent is above a certain level. One piece of advice I've seen (specifically in the context of academic pure mathematics) is that you shouldn't become a mathematician unless you couldn't bear not to. Because mathematics research is really hard, and it will kick your ass, and how successful you are will have a lot to do with how you cope when it does.

(My own background: got the PhD, did a couple of years of postdoc, was quite staggeringly unproductive, got out of academia and into industry, have been reasonably happy there. Probably happier than I'd have been as a struggling academic. Most academics are struggling academics, especially for, say, the first 5-10 years after getting their PhDs.)

Some questions you might want to answer for yourself:

  • If you go to grad school, get your PhD, and then don't go into academia, is that a good outcome or a bad one?
  • If you don't take the academic path, what will you do instead?
  • Whichever way you go, regrettably there's a very good chance that you won't end up revolutionizing the world. If you compare possible academic futures with possible non-academic futures, and make the assumption that you do just OK -- which feels like the better outcome?
In response to comment by gjm on Assessing oneself
Comment author: polymer 30 September 2014 01:23:20AM 1 point [-]

So, my point regarding the speed.

In the middle of working out a problem, I had to find the limit of

S = 1/e + 2/e^2 + ... + n/e^n + ...

I had never seen this sum before, so now cleverness is required. If I assumed guess C was true, that would imply

e/(e - 1) = (e - 1)S

This claim is much easier to check,

(e - 1)S = 1 + 1/e + 1/e^2 + ... = 1/(1 - 1/e) = e/(e - 1)

We know what S is, and the solution to the problem follows. In retrospect, I understand one method for how I could find the answer. But during the test, I can't see through the noise fast enough (although I can smell the clue). I could go through each guess one by one, but I'm just too slow. Maybe there's something else I'm missing that would've made the guess simpler, but that's what I'm basing the slow opinion off of.

I don't know if being slow at inference in this sense is a barrier, or indicative, of deeper creativity issues (or if I'm just suffering from the availability heuristic.)

Anyways your questions all very good, I don't care for academia perse, I care about the questions. If I don't keep doing academic stuff, I would hope I would've formed enough connections to find some route towards practical problems that still require some creativity.

Your last question is very interesting. I'm not sure how to answer it. My unhealthy worry, I think, is I really don't like wasting peoples time. I suppose I don't care about either being "just OK", if "just OK" isn't wasting peoples time, but I still get to be creative.

I guess I don't want to be a pundit? I mean I'll teach, but I'd be much happier if I was doing something theoretically. If this is impossible for me, I'd like to know the reasons why, and fail out as soon as possible.

Your questions are very interesting though, I still need to think about them more. Thank you for your thoughts, they give very good context to think about this, and its clear you've worried about analogous issues.

In response to Assessing oneself
Comment author: shminux 26 September 2014 09:01:39PM 16 points [-]

It's not clear to me from your post if you have any specific terminal-like goals in mind. Do you want to just "do research"? Or to teach? Or to "do good"? Or what?

In response to comment by shminux on Assessing oneself
Comment author: polymer 30 September 2014 12:55:41AM 1 point [-]

I'm not sure. I'm trying to work towards a career path which uses as much of my ability as I can. The most important job for a professional programmer, was understanding what your client wanted. This is a fine job, but being good at algorithms isn't necessarily a requirement.

When talking to an engineer at Google, I asked what he thought a good career choice was for working on hard problems. His immediate first thought was graduate school, then he sort of mentioned robotics.

My ideal dream isn't being a professor, it's working on something that needs inference, that uses my mathematical abilities. So I'm leaning towards research, but that's the implication not necessarily the goal.

Teaching isn't the goal, hands on altruism isn't the goal. Fitting into a place where I'm using as much of my skill set as possible, is the goal.

And that is a terminal goal, I can do boring stuff in the mean time. My point for jumping out of programming, was exactly that the math wasn't the important part, it was the picture. The math is important to someone else. I'd like to be that someone else.

I try to explain this to people though, and almost all of them think I'm being way to vague (or they don't understand). You go to school because that's the only way you're going to study the distribution of zeroes for the Wronskian of orthogonal polynomials. I've had maybe one professor discourage me from being too picky...

Comment author: gjm 26 September 2014 07:47:38PM 12 points [-]

It seems unlikely that an IQ test gives very much extra information about polymer's prospects as a mathematician or physicist, on top of his/her experiences and scores studying mathematics and physics at university.

In response to comment by gjm on Assessing oneself
Comment author: polymer 26 September 2014 08:42:32PM 4 points [-]

I agree, that I have a wealth of information to work with right now. Just trying to honestly balance it (felt like LW fit the theme somewhat).

On the one hand, both of those scores are my first time, and they were taken cold. And, I could argue I thought a lot of homework in school was unimportant and unnecessary (because of a poor philosophical attitude).

But of the 26 questions wrong or incomplete on the practice Math subject test, roughly 16 of them I had sufficient knowledge, but I simply wasn't fast enough. And the Algebra class, was really hard, and I did do homework eventually.

It's not like I haven't been very successful in some courses. Graduate Complex Analysis, and stochastic processes come to mind. And the admissions director at my undergrad (University of Oregon) has told me directly I am ready for graduate school, but he would prefer I went to a better school.

I'm just lost. It seems in this context, failure speaks louder then success. Even if I was smart enough, perhaps I simply haven't worked hard enough (or on the right things). The practical consequence would be the same. I wish I knew what the admissions officer saw, it's hard to suppress the feeling he's only saying that because I did well in his courses.

Assessing oneself

13 polymer 26 September 2014 06:03PM

I'm sorry if this is the wrong place for this, but I'm kind of trying to find a turning point in my life.

I've been told repeatedly that I have a talent for math, or science (by qualified people). And I seem to be intelligent enough to understand large parts of math and physics. But I don't know if I'm intelligent enough to make a meaningful contribution to math or physics.

Lately I've been particularly sad, since my score on the quantitative general GRE, and potentially, the Math subject test aren't "outstanding". They are certainly okay (official 78 percentile, unofficial 68 percentile respectively). But that is "barely qualified" for a top 50 math program.

Given that I think these scores are likely correlated with my IQ (they seem to roughly predict my GPA so far 3.5, math and physics major), I worry that I'm getting clues that maybe I should "give up".

This would be painful for me to accept if true, I care very deeply about inference and nature. It would be nice if I could have a job in this, but the standard career path seems to be telling me "maybe?"

When do you throw in the towel? How do you measure your own intelligence? I've already "given up" once before and tried programming, but the average actual problem was too easy relative to the intellectual work (memorizing technical fluuf). And other engineering disciplines seem similar. Is there a compromise somewhere, or do I just need to grow up?

classes:

For what it's worth, the classes I've taken include Real and Complex Analysis, Algebra, Differential geometry, Quantum Mechanics, Mechanics, and others. And most of my GPA is burned by Algebra and 3rd term Quantum specifically. But part of my worry, is that somebody who is going to do well, would never get burned by courses like this. But I'm not really sure. It seems like one should fail sometimes, but rarely standard assessments.

Edit:

Thank you all for your thoughts, you are a very warm community. I'll give more specific thoughts tomorrow. For what it's worth, I'll be 24 next month.

 

Double Edit:

Thank you all for your thoughts and suggestions. I think I will tentatively work towards an applied Mathematics PHD. It isn't so important that the school you get into is in the top ten, and there will be lots of opportunities to work on a variety of interesting important problems (throughout my life). Plus, after the PHD, transitioning into industry can be reasonably easy. It seems to make a fair bit of sense given my interests, background, and ability.

Comment author: gjm 26 August 2014 01:09:03AM *  0 points [-]

[...] is a true statement coming from math logic, [...] is a false statement coming from human interaction

My reading of polymer's statement is that he wasn't using "plausible" as a psychological term, but as a rough synonym for "probable". (polymer, if you're reading: Was I right?)

P(B|A) = 1 which makes A and B essentially the same

No, P(B|A) is a little less than 1 because Beth might have read the email carelessly, or forgotten bits of it.

[EDITED to add: If whoever downvoted this would care to explain what they found objectionable about it, I'd have more chance of fixing it. It looks obviously innocuous to me even on rereading. Thanks!]

Comment author: polymer 31 August 2014 09:06:21PM *  0 points [-]

I'm not quite sure what the following means:

if you add details to a story, it becomes less plausible" is a false statement coming from human interaction.

I don't care whether it's false as a "human interaction". I care whether the idea can be modeled by probabilities.

Is my usage of the word plausible in this way really that confusing? I'd like to know why... Probable, likely, credible, plausible, are all (rough) synonyms to me.

Comment author: gjm 25 August 2014 06:33:30PM 4 points [-]

A&B gains more evidence than A from the experiment. It doesn't (and can't) become more probable.

Let's have an example. Someone is flipping a coin repeatedly. The coin is either a fair one or a weighted one that comes up heads 3x as often as tails. (A = "coin is weighted in this way".) The person doing the flipping might be honest, or might be reporting half the tails she flips (i.e., each one randomly with p=1/2) as heads. (B = "person is cheating in this way".)

Let's say that ahead of time you think A and B independently have probability 1/10.

Your experiment consists of getting the (alleged) results of a single coin flip, which you're told was heads.

So. Beforehand the probability of A was 1/10 and that of B was 1/100.

The probability of your observed results is: 1/2 under (not-A,not-B); 3/4 under (not-A,B); 3/4 under (A.not-B); and 7/8 under (A,B).

So the posterior probabilities for the four possibilities are proportional to (81:9:9:1) times (4:6:6:7); that is, to (324:54:54:7). Which means the probability of A has gone up from 10% to about 14%, and the probability of A&B from 1% to about 1.6%.

So you've got more evidence for A&B than for A, which translates (more or less) to a larger relative gain in probability for A&B than for A. But A&B is still less likely.

If you repeat the experiment and keep getting heads, then A&B will always improve more than A alone. But the way this works is that after a long time almost all the probability of A comes from the case where A&B, so that A&B's advantage in increase-in-probability gradually goes away.

Comment author: polymer 25 August 2014 08:35:13PM *  0 points [-]

So plausibility isn't the only dimension for assessing how "good" a belief is.

A or not A is a certainty. I'm trying to formally understand why that statement tells me nothing about anything.

The motivating practical problem came from this question,

"guess the rule governing the following sequence" 11, 31, 41, 61, 71, 101, 131, ...

I cried, "Ah the sequence is increasing!" With pride I looked into the back of the book and found the answer "primes ending in 1".

I'm trying to zone in on what I did wrong.

If I had said instead, the sequence is a list of numbers - that would be stupider, but well inline with my previous logic.

My first attempt at explaining my mistake, was by arguing "it's an increasing sequence" was actually less plausible then the real answer, since the real answer was making a much riskier claim. I think one can argue this without contradiction (the rule is either vague or specific, not both).

However, it's often easy to show whether some infinite product is analytic. Making the jump that the product evaluates to sin, in particular, requires more evidence. But in some qualitative sense, establishing that later goal is much better. My guess was that establishing the equivalence is a more specific claim, making it more valuable.

In my attempt to formalize this, I tried to show this was represented by the probabilities. This is clearly false.

What should I read to understand this problem more formerly, or more precisely? Should I look up formal definitions of evidence?

Comment author: polymer 25 August 2014 04:57:00PM *  2 points [-]

Can someone link to a discussion, or answer a small misconception for me?

We know P(A & B) < P(A). So if you add details to a story, it becomes less plausible. Even though people are more likely to believe it.

However, If I do an experiment, and measure something which is implied by A&B, then I would think "A&B becomes more plausible then A", Because A is more vague then A&B.

But this seems to be a contradiction.

I suppose, to me, adding more details to a story makes the story more plausible if those details imply the evidence. Sin(x) is an analytic function. If I know a complex differentiable function has roots on all multiples of pi, Saying the function is satisfied by Sin is more plausible then saying it's satisfied by some analytic function.

I think...I'm screwing up the semantics, since sin is an analytic function. But this seems to me to be missing the point.

I read a technical explanation of a technical explanation, so I know specific theories are better then vague theories (provided the evidence is specific). I guess I'm asking for clarifications on how this is formally consistent with P(A) > P(A&B).

Comment author: shminux 24 August 2014 06:22:37AM *  4 points [-]

They are a nice supplementary material and an engaging read, but are not suitable as the main text for learning a given topic for the first time.

Comment author: polymer 25 August 2014 06:35:13AM 4 points [-]

I disagree, I read the Feynman lectures in high school and learned a great deal. His presentation taught me more about how to think about these things then Giancoli did.

Giancoli better prepared me for what the standard format was for test questions, but it didn't really articulate how I was supposed to use the ideas to generate new ones. Feynman's style of connecting claims with whatever you happened to know, is extremely important. Giancoli doesn't demonstrate this style quite as well.

Of course it was my first textbook, so I could go on and on about why I like it...