The subtle but key part to his comment is "English text". English sentences are not random. Some words are much more likely to follow other words, and of course there are only 80,000 configurations of letters to begin with (ie, words). However, a pass phrase composed of 8 random words is actually pretty strong, over 200 bits of entropy: http://dkn255hz262ypmii.onion/index.php?topic=106496.msg730353#msg730353 You can memorize 8-16 words. (And yes I know you just saw that in the Security thread, but I'm making sure people here see it too. )