He doesn't acknowledge it explicitly, but my reading is that the author will acknowledge that he himself sometimes jumps to conclusion. This is his definition of stupid, so he likely does agree that he's stupid sometimes. He's trying to do it less, but it's impossible to get through life without making assumptions -- we don't have the time or energy to thoroughly analyze every little thing.
He doesn't acknowledge it explicitly, but my reading is that the author will acknowledge that he himself sometimes jumps to conclusion. This is his definition of stupid, so he likely does agree that he's stupid sometimes. He's trying to do it less, but it's impossible to get through life without making assumptions -- we don't have the time or energy to thoroughly analyze every little thing.