Both of them are inaccurate and useless.
I can not speak for usefulness but "Human stupidity is formidable but not invincible" doesn't seem too off the mark. I suppose it depends on which territory we are considering the stupidity to be formidable in defense of.
This is our monthly thread for collecting these little gems and pearls of wisdom, rationality-related quotes you've seen recently, or had stored in your quotesfile for ages, and which might be handy to link to in one of our discussions.