Today's post, Math is Subjunctively Objective was originally published on 25 July 2008. A summary (taken from the LW wiki):

It really does seem like "2+3=5" is true. Things get confusing if you ask what you mean when you say "2+3=5 is true". But because the simple rules of addition function so well to predict observations, it really does seem like it really must be true.

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 Can Counterfactuals Be True?, 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.