= 27d567bc2d48d9f40e9ccc20ea370b15)
Perplexed comments on Justifying Induction - Less Wrong
You are viewing a comment permalink. View the original post to see all comments and the full post content.
= 783df68a0f980790206b9ea87794c5b6)
Loading…= b715d02e85f7b3b4ae65ca3d3e450868)
Subscribe to RSS Feed
Powered by Reddit
= f037147d6e6c911a85753b9abdedda8d)
You are viewing a comment permalink. View the original post to see all comments and the full post content.
Comments (33)
ETA 2: this tile reads as if it is justifying induction as a principle, rather than when it is justifying induction in particular. Insifar as it is not addressing the problem o induction, it is on-point. I just don't think that point is terribly interesting, as it basically says "what counts as evidence depends on what we want to prove." My original comment follows, and applies if this was supposed to be about the problem of induction. I think you fundamentally misunderstand the problem of induction. The very concept of causation and updating on evidence rests on the assumption induction is possible. Without induction, there is no Bayes's theorem, because the very concept of evidence presupposes induction.
The problem of induction is, in short, how do we know that the future will be like the past? How do we know that our current observations at truly evidence of what the future will be like? The only evidence we have is that the future has always been like the past. Thus, the only evidence to justify induction presumes induction is possible.
This post does not appear to have anything to do with that. You can't use Bayesian evidence for induction, because the very concept of Bayesian evidence presupposes induction to be valid. ETA: stating that Bayes theorem presupposes induction may have been a bit strong. The point is that the thing that feeds into Bayes' presumes induction. Without induction, you cannot update on evidence, because "evidence" is a hollow concept. Bayes may not technically depend on induction; it's just that any actual application of it to the real world does.
Response to ETA 2.
I agree with your point that the question of the validity of Bayesian inference and the question about whether the future will be "like" the past are two logically independent questions. I also agree that it is convenient to use "the problem of induction" as a label for questions related to the "similarity" of past and future. Hence, I agree that the posting does not really help to solve "the problem of induction".
What does help? Well one argument goes like this: "If you believe the future is not like the past, then you must believe that the present is very special; that it is a boundary point between a stretch of time which is one way, and a stretch of time which is quite different. What is your justification for your belief in the special quality of the present? Perhaps your only possible move is to claim that the present is not special; that all points in time are boundary points. But we have evidence that this is not the case; the first half of the past is visibly similar to the second half of the past, for example."
This, of course is not an airtight argument. But it does show that someone who denies the validity of induction is likely to be forced into much more convoluted explanations of the evidence than would someone who adopts the simple hypothesis that "all points in time are pretty much alike". So, in a sense, induction reduces to Occam's razor.