16. The spirits of Mercury are more than usually proud of their knowledge. So they were told that, even though they knew countless facts, there is still an infinite number they do not know; and even if they went on increasing their knowledge for ever, they could still not achieve an acquaintance with all general principles. As for being proud and puffed up, they were told this was not proper. But they replied, by way of excusing their faults, that it was not pride, but merely boasting about the excellence of their memory.