empty log files

I can't recall doing anything 'wrong' but I now notice most of my log files are, unexpectedly, empty (see example, below). Anybody care to suggest how I can debug why this is so? Thanks, M mkb@veri:/var/log$ ls -lt |head -33 total 163828 -rw-rw-r-- 1 root utmp 321792 2008-07-01 10:29 wtmp -rw-r--r-- 1 root root 28525 2008-07-01 10:14 Xorg.0.log drwxr-xr-x 2 root root 4096 2008-07-01 10:14 gdm/ -rw-r--r-- 1 root root 26360 2008-07-01 10:13 dmesg drwxr-xr-x 2 root root 4096 2008-07-01 10:13 sa/ -rw-r--r-- 1 root root 292584 2008-06-30 22:43 lastlog -rw------- 1 root utmp 164902656 2008-06-30 22:28 btmp drwxr-xr-x 2 lp sys 4096 2008-06-30 20:52 cups/ drwx------ 2 root root 12288 2008-06-30 20:00 tiger/ -rw-r--r-- 1 root root 29008 2008-06-30 16:49 Xorg.0.log.old -rw-r--r-- 1 root root 52438 2008-06-30 09:13 rpmpkgs -rw------- 1 root root 252 2008-06-29 17:08 yum.log -rw------- 1 root root 0 2008-06-29 04:38 boot.log -rw------- 1 root root 0 2008-06-29 04:38 cron -rw------- 1 root root 0 2008-06-29 04:38 maillog -rw------- 1 root root 0 2008-06-29 04:38 messages -rw------- 1 root root 0 2008-06-29 04:38 secure drwxr-xr-x 2 root root 4096 2008-06-29 04:38 setroubleshoot/ -rw------- 1 root root 0 2008-06-29 04:38 spooler -rw-r--r-- 1 root root 52403 2008-06-28 04:39 rpmpkgs.1 drwxr-x--- 2 root root 4096 2008-06-26 22:59 audit/ -rw-r--r-- 1 root root 827985 2008-06-25 10:46 scrollkeeper.log -rw------- 1 root root 30920 2008-06-25 10:46 yum.log.1 -rw------- 1 root root 0 2008-06-23 14:30 boot.log.1 -rw------- 1 root root 0 2008-06-23 14:30 cron.1 -rw------- 1 root root 0 2008-06-23 14:30 maillog.1 -rw------- 1 root root 0 2008-06-23 14:30 messages.1 -rw------- 1 root root 0 2008-06-23 14:30 secure.1 -rw------- 1 root root 0 2008-06-23 14:30 spooler.1 -rw-r--r-- 1 root root 52208 2008-06-21 04:39 rpmpkgs.2 -rw------- 1 root root 0 2008-06-15 04:38 boot.log.2 -rw------- 1 root root 0 2008-06-15 04:38 cron.2