Today's post, Underconstrained Abstractions was originally published on 04 December 2008. A summary (taken from the LW wiki):

The problem with selecting abstractions is that for your data, there are probably lots of abstractions that fit the data equally well. In that case, we need some other way to decide which abstractions are useful.

Discuss the post here (rather than in the comments to the original post).

This post is part of the Rerunning the Sequences series, where we'll be going through Eliezer Yudkowsky's old posts in order so that people who are interested can (re-)read and discuss them. The previous post was Permitted Possibilities, & Locality, and you can use the sequence_reruns tag or rss feed to follow the rest of the series.

Sequence reruns are a community-driven effort. You can participate by re-reading the sequence post, discussing it here, posting the next day's sequence reruns post, or summarizing forthcoming articles on the wiki. Go here for more details, or to have meta discussions about the Rerunning the Sequences series.