'Lewising' the Metaphor

Blue Spectacles
Kantian Optics
Google Images

In his essay "Bluspels and Flalansferes: A Semantic Nightmare" (pdf), which I noted yesterday, C.S. Lewis explores the putative loss of a hypothetical metaphor's etymological origin, treating what he calls the Master's Metaphor, i.e., a metaphor used by a teacher to illuminate the meaning of some difficult topic, in this instance, the meaning of the Kantian categories of understanding, such as the category of causality, which 'colors' our perception of reality somewhat like wearing a pair of blue spectacles would:

The question of the Master's Metaphor need not detain us long. I may attempt to explain the Kantian philosophy to a pupil by the following metaphor. 'Kant answered the question "How do I know that whatever comes round the corner will be blue?" by the supposition " I am wearing blue spectacles."' In time I may come to use 'the blue spectacles' as a kind of shorthand for the whole Kantian machinery of the categories and forms of perception. And let us suppose, for the sake of analogy with the real history of language, that I continue to use this expression long after I have forgotten the metaphor which originally gave rise to it. And perhaps by this time the form of the word will have changed. Instead of the 'blue spectacles' I may now talk of the bloospel or even the bluspell. If I live long enough to reach my dotage I may even enter on a philological period in which I attempt to find the derivation of this mysterious word. I may suppose that the second element is derived from the word spell and look back with interest on the supposed period when Kant appeared to me to be magical; or else, arguing that the whole word is clearly formed on the analogy of gospel, may indulge in unhistorical reminiscences of the days when the Critique seemed to me irrefragably true. But how far, if at all, will my thinking about Kant be affected by all this linguistic process? In practice, no doubt, there will be some subtle influence; the mere continued use of the word bluspel may have led me to attribute to it a unity and substantiality which I should have hesitated to attribute to 'the whole Kantian machinery of the categories and forms of perception'.

Lewis is exploring the way in which metaphors die, though he doesn't consider "bluspel" an example of such, apparently because he is describing a teacher who understands Kant well but has forgotten the coining of "bluspel." The metaphor has been entirely lost. Lewis's point is one I'll have to read and reflect upon, but I really like the metaphor --  blue spectacles do help to see what Kant meant.

Unless one takes the analogy too far, of course, and thinks that causality is a depressing concept (where's our free will?), and that's why it's like blue spectacles, which give us the blues about everything . . .