Augustine: “I know that this remains to be untied by us, and I promised to explain it at the outset – but, because the matter is extremely subtle, and demands of the mind eyes quite different than those that human habit is accustomed to have in the affairs of everyday life,I warn you that you must go willingly along that path by which I think it necessary that you be led, and do no grow tired because of these necessary detours of mine so that you take it ill how long you need to get to where you want to go. For first, I ask of you whether you think that there’s any body that does not, in its own fashion, have a certain length, width, and depth?”
Evodius: “I don’t understand what you mean by ‘depth.'”
A: “I mean that by which it comes about that the interiors of bodies may be thought, or, ever perceived – if they are transparent, like glass. But if you take this property way from bodies, as far as my opinion goes, they cannot be perceived, nor indeed by correctly thought to be bodies at all. Now I want you to tell me what you think about this.”
E: “Indeed I do not doubt that any body can lack these things.”
(Students of Latin will know that, where English has two sets of pronouns which distinguish between “surface” and “space” – on/in, over/through, etc. – Latin has only one. In its lexicon, too, one encounters certain words that elide the distinction between two and three dimensions. Orbis, for example, means either a circle or a sphere; sphaera, which indicates a sphere unambiguously, is a borrowing from Greek.
This is the first passage I’ve ever encountered that suggests this feature of Latin may actually have presented cognitive problems to speakers of the language. To anyone who reads the text in English, it’s obvious what Augustine means by depth – the third dimension, the one that distinguishes between surface and space – and, conversely, the difficulties experienced by Evodius in understanding this usage seem incomprehensible. A Latin speaker, however – especially one who, like Augustine and most of his circle at Cassiacum, does not know Greek – might have found this distinction less intuitive.)