Explaining with Metaphor

by F.

I was reading a copy of this book, which is without question a good read. But one thing bugged me about the presentation. It took me a while to put my finger on it, but I think the author succumbs to a temptation a lot of philosophers succumb to: they get carried away with metaphor.

Metaphor is wonderful for explaining. An ant colony functions like a complicated watch. The planets move like billiard balls through space. Crowds move over city streets like flocks of birds. Stuff like that works because it casts the relatively unfamiliar in terms of the relatively familiar. You may not have seen an ant colony, but you’ve seen a watch (or a picture of one). That’s how metaphor does its magic: it builds on what you know, then extends it into a new domain.

But the author casts unfamiliar concepts in terms of…the unfamiliar. He makes up neologisms which are then used to explain some fairly subtle concepts from statistics and probability. So he puts the unknown in terms of the unknown, and explanation suffers. It’s still entertaining, and I like–maybe even love–the book. But I wondered: Wouldn’t this have been better if the metaphors brought things a little closer to earth?

I suppose the complementary vice is that the metaphor begins to take over, which is a problem generally with pop science. This seems especially true in physics and “chaos theory,” where some of the concepts are so strange that they have to be recast in terms of the very familiar. Yet the recasting is so complete that meaning is perverted. Hippies on the bus are suddenly talking about string theory and chaos and fractals. “Dude! It’s totally Mandelbrotian! Like, Julia set and shit!”

There’s no clear answer, no algorithm to tell you when you’ve pushed the metaphor too far. You’re left with the casuistry of the craftsman, and all advice starts to sound Polonious-like:

And these few precepts in thy memory
See thou character. Give thy thoughts
no tongue, Nor any unproportioned thought his act.
Be thou familiar, but by no means vulgar.
Those friends thou hast, and their adoption tried,
Grapple them to thy soul with hoops of steel;
But do not dull thy palm with entertainment
Of each new-hatch’d, unfledged comrade.
Beware of entrance to a quarrel, but being in,
Bear’t that the opposed may beware of thee.
Give every man thy ear, but few thy voice;
Take each man’s censure, but reserve thy judgment.
Costly thy habit as thy purse can buy,
But not express’d in fancy; rich, not gaudy;
For the apparel oft proclaims the man,
And they in France of the best rank and station
Are of a most select and generous chief in that.
Neither a borrower nor a lender be;
For loan oft loses both itself and friend,
And borrowing dulls the edge of husbandry.
This above all: to thine ownself be true,
And it must follow, as the night the day,
Thou canst not then be false to any man.

To which I would add: there is only casuistry.