I hesitate to comment on ducks and robins after reading the comment thread, but when I think about ducks and robins I picture the duck swimming on the duck pond and the robin sitting on a branch of a tree overhanging the duck pond. Prod me to to think about disease transmission and I picture the robin shitting in the water in which the duck is diving for weeds to eat. Guess which way I imagine disease transmission going :-)
Today's post, Typicality and Asymmetrical Similarity was originally published on 06 February 2008. A summary (taken from the LW wiki):
You try to treat category membership as all-or-nothing, ignoring the existence of more and less typical subclusters.
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 Similarity Clusters, 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.