[HN Gopher] A Cookbook of Self-Supervised Learning
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       A Cookbook of Self-Supervised Learning
        
       Author : ZunarJ5
       Score  : 79 points
       Date   : 2023-04-25 16:13 UTC (6 hours ago)
        
 (HTM) web link (arxiv.org)
 (TXT) w3m dump (arxiv.org)
        
       | cs702 wrote:
       | Nice. It looks like it will be useful... although best practices
       | are likely going to continue to evolve. The biggest question in
       | my mind is whether we can come up, at some point in the future,
       | with a kind of universal self-supervised learning objective that
       | works well in practice for any task.
        
         | nmaley wrote:
         | The NFL theorem means nothing if all the learning tasks have a
         | common underlying structure. In the real world, they do. The
         | laws of physics and chemistry create emergent causal
         | relationships. Any SSL learning algorithm that learns to
         | exploit causal relationships will consistently perform well
         | over a variety of real world tasks.
        
         | medo-bear wrote:
         | no such thing as free lunch -
         | https://en.m.wikipedia.org/wiki/No_free_lunch_theorem
        
           | tomrod wrote:
           | We really need to revise this to say "there is no global free
           | lunch."
           | 
           | You can and often do get local free lunches.
        
             | medo-bear wrote:
             | the question was about "objective that works well in
             | practice for any task". thats pretty global in my books
        
               | karpierz wrote:
               | If you take "any task" to mean literally any conceivable
               | task, then sure.
               | 
               | If you take "any task" to mean "any practical task" or
               | "any task a human would conceivably want to have done",
               | then no free lunch doesn't apply.
        
               | tbalsam wrote:
               | Another way of looking at karpierz's comment is through
               | the incompressibility of pure noise at scale.
               | 
               | As soon as some infinitely generated sort of noise is
               | from some subset of possible noise, there is indeed
               | (AFAIK) some kind of an ideal estimator that
               | appropriately compresses that noise source with no bias
               | and less entropy that the full space of possible noise.
               | 
               | I hope this shines an additional alternative light on the
               | topic.
        
           | tbalsam wrote:
           | The most common statement I make is about the misapplication
           | of the NFL.
           | 
           | This is not an appropriate use of the NFL.
           | 
           | The original commenter is asking about a general solution
           | that will work well for all problems presented at it. The NFL
           | details fine-grained tradeoffs in _ideal solutions_ for
           | specific traits in certain areas. Additionally, we're not
           | operating in an unbiased space here, so trivially there is a
           | best estimator without bias. So by that very fact alone the
           | NFL is invalidated in terms of the method it is being applied
           | in here.
           | 
           | This is something I feel frustrated seeing a lot of younger
           | people entering the field do (not saying you are young or
           | new, it's just the trend). If this was the case in this kind
           | of a way we never would have gotten beyond MLPs.
           | 
           | Yes, indeed there is in fact a set of general solutions that
           | works roughly well over everything and is biased towards the
           | situations where people will need it the most.
           | 
           | No, it will likely not be the technically best performing
           | solution.
           | 
           | What the OP is looking for I believe is convenience,
           | stability, and reliably good performance.
           | 
           | Hence, the NFL is not applicable or relevant to this matter
           | in the way it is being used.
        
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       (page generated 2023-04-25 23:00 UTC)