Okay, I know this is a case of dragging something up from the depths of beyond, but anyway… The column on 09-Apr-1976 about ‘Why do cats purr? Why do Cheshire cats grin?’ misses an alternative explanation for the existence of the Cheshire Cat, which may be merely incidental, but quite interesting nonetheless.
Carroll was a logician, in addition to a storyteller, as anyone can tell you. Alice in Wonderland contains inumerable philosophy in-jokes, and the Cheshire Cat’s grin is one of them. A vague idea as to why goes as follows. (And this is highly nutshelled so forgive any glaring errors, all those who are more learned in philosophy than I am).
In philosophy, things that ‘are’ can generally be regarded as substances. Properties of that substance are known as its predicates. For example, you can have a tree. It’s a substance. The tree can be tall. Or bushy. Or responsible for six murders last autumn. Those are its predicates, and although they provide different examples of trees with different characteristics, they don’t detract from each tree’s inherent treeliness.
Another substance is a cat. Its predicates might be that the cat is wet. Or that it is rather fat. Or that it is grinning. Whatever - as long as it is something additional to our knowledge about the cat, then it is a predicate.
Furthermore, some predicates of ‘cat’ are necessary for catliness. As in, it is necessary that all cats are feline. It is not however necessary that all cats are grinning. Specifying that cat x is currently grinning is vaguely useful because it might be the case in some other world that it is not grinning (e.g. when it’s just been kicked or something). However, specifying that cat x is currently feline is less satisfactory because that’s part and parcel of the ‘cat’ bit. If you know what a cat is, you know also that the cat is feline. (Regardless of whether you know you know). So there’s a differentiation between predicates that are necessarily defined by part of the definition of the substance (e.g. felineness of cat x), and predicates that just happen along once in a blue moon, for which it’s neither here nor there to the actual substance whether or not they’re going on (e.g. the grinning). You can separate out the latter from the substance, but the former are bundled up within the definition of the substance. A grin is incidental. Felineness is not.
So what? The point of all this is that you can’t have ‘rather fat’ or ‘wet’ or ‘grinning’ without something to assign the terms to. As in, a grin cannot exist on its own - it needs a mouth at the very least. (Get out of your mind the silly pictures in the cartoon version of a grin floating in the air - that’s still got a substance in terms of the mouth). Similarly, there’s no concept of wetness that doesn’t have some substance as its foundation. You can’t visualise either a grin or wetness without something to be grinning or something to be wet.
So the idea here is that the substance of the Cheshire Cat leaves behind its incidental predicate, the grin. It’s rather odd to think of a grin without a face, but there it is. Carroll is intentionally confusing the ideas. In reality, there’s no way the grin can go anywhere without there being some cat x to ground it. Yet in Carrol’s wonderland, predicates are as free to traipse mud through the shagpile as any substance has ever been.