500 Errors in Wordpress

I haven’t changed anything on my site in a long time. It was working fine until recently. I can still view the home page and all the admin pages. Blog posts, however, have started giving a 500 error:

AH00124: Request exceeded the limit of 10 internal redirects due to probable configuration error. Use 'LimitInternalRecursion' to increase the limit if necessary. Use 'LogLevel debug' to get a backtrace.

I’ve already reset file permissions, disabled all plugins, and turned on WP debugging. Nothing has made a difference. I don’t know if there’s anything else to try… it doesn’t seem like there’s any way to actually “Use ‘LogLevel debug’” to see what the redirects are.