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Comments from Frankston, Reed, and Friends

Wednesday, March 12, 2003

DPR at 4:02 PM [url]:

Salon article on the myth of interference.

David Weinberger wrote a Salon article on the myth of interference that appeared today. It's already been heavily slashdotted.

And of course, there are the usual angry letters that seem to think I'm claiming to have discovered the earth is flat, or that relativity is wrong (someone actually thought I was arguing that!)

What I am actually saying is pretty boring to physicists, I would think. (What I'm saying is that because radio propagation is amazingly linear, any orthogonal basis function set will do to separate independent signals. Since each transmitter is at a different point in spacetime, signals it transmits are by definition orthogonal to signals transmitted by all other antennas, at nearly all points in space. This is true in free space, but also in space that contains matter.)

It's more exciting to RF engineers, who use approximations to the physics involved. Their approximations (ideas like "fading" and "interference") become real in their minds and textbooks. And in turn, the approximations are too complicated, so they get replaced by approximate models of the approximations ("fading probability distributions" that model "fading" as if it were a real random phenomenon, rather than a phenomenon of certain kinds of antenna-detector-modulation system choices). They believe in their approximations. They are rules of thumb that help them get a job done. And in that sense, they are useful.

And it's apparently quite exciting to folks whose experience with radio systems is somewhat limited. Exciting enough to generate angry mail and postings.

But "interference" is only a metaphor - an image that captures some of the behavior of a system. It's even a useful metaphor most of the time.

But metaphors are sometimes unhelpful - they cloud the mind, rather than clear it. And as I've seen, challenging a metaphor apparently makes some people very angry. Rather than wanting to learn more, they attack the messenger, accusing me of all sorts of things.

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