What do I mean by abstractness? You can point to a real live cow chewing its cud in a pasture and equate it with the letters c-o-w on the page. But you can’t point to a real live plus sign that the symbol “+” is modeled after—the idea underlying the plus sign is more abstract. By encryptedness, I mean that one symbol can stand for a number of different operations or ideas, just as the multiplication sign symbolizes repeated addition.
