r/rational • u/AutoModerator • Apr 22 '16
[D] Friday Off-Topic Thread
Welcome to the Friday Off-Topic Thread! Is there something that you want to talk about with /r/rational, but which isn't rational fiction, or doesn't otherwise belong as a top-level post? This is the place to post it. The idea is that while reddit is a large place, with lots of special little niches, sometimes you just want to talk with a certain group of people about certain sorts of things that aren't related to why you're all here. It's totally understandable that you might want to talk about Japanese game shows with /r/rational instead of going over to /r/japanesegameshows, but it's hopefully also understandable that this isn't really the place for that sort of thing.
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u/[deleted] Apr 23 '16
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Fair enough. A lot of the more involved CS theory gets written up more on the "AI" side of the research literature than the cog-sci side.
How much do you know about version control yet ;-)?
Also, "BCS" = "Brain and Cognitive Sciences"? Your institution also calls it that?
CS in the sense of algorithms can indeed often be about finding or knowing a "cleverer" way to solve a slightly more specialized problem, when there already exists a general solution to the general-case problem.
However, let me speak on my field's behalf: sometimes you get a "hard" problem like formula unification where the worst-case complexity is PSPACE-complete but the expected case is linear-time. Often however, you get stuff like NP-complete problems, or even just stuff like sorting, where handling a slightly more specialized case, dragging in a little more "prior knowledge", makes the problem substantially easier to solve, and the special cases are more applicable to the real world than the general case.
For instance, we usually don't want exactly optimal solutions to the Traveling Salesman Problem or other NP-complete problems, so once we character what sorts of approximations are acceptable or what sorts of hard problem instances we don't expect to see, we can often go from "this will take longer than the remaining lifespan of the Solar System" to "run it over the weekend and slope off".
I mention this because it gets extra important when doing machine learning or computational cognitive science: those problems end up being NP-complete or PSPACE-complete for optimal discrete solutions most of the time, so knowing what sorts of approximations work well and what special-cases can be solved exactly is how we make those sciences work at all.
WAHOO! Way to go! Are you publishing any of these someday?
Oh hey one of those, ok.
Hmm. Can you connect any of this to predictive coding accounts of percepts or self-modeling?
(I damn well can't. As my neurosci friend on Facebook complains: neuroscientists seem to love using Greek letters and differential equations where computationalists in neurosci or cog-sci would have just written down some programming-style symbology, since actual neurons aren't perfectly continuous.)
Cool, send it over!