Metaphors, Science and Cardiology

One day, I want to compile a collection of all the metaphors that have shaped modern science. The sciences of the mind, perhaps because we know so little about the mind, have been particularly vulnerable to the lure of facile analogy. There's the classic "mind-as-computer" metaphor which, although useful, is certainly imperfect. Before computers, the mind was compared to "holograms," "telephone switchboards" and "hydraulic pumps". It seems that we can hardly invent a new technology before we feel the need to impose it onto the mysterious workings of the brain.

Of course, every science has its metaphors. String theory has its famous garden hose, electrons whirl in an indeterminate "cloud" and the genetic code is an "alphabet". It's easy to pretend that these metaphors aren't important, and that they don't shape our scientific concepts and experiments. But that would be naive. Just look at cardiologists, who have been comparing the cardiovascular system to home plumbing for decades:

The plumbing analogy causes serious confusion regarding heart disease, and as a result, we've wasted a lot of time and money on cardiac angioplasty that does no good....It turns out there's a right and wrong place for the plumbing analogy. It's right for people who have heart attacks that involve a sudden, total blockage of a coronary artery. That's why procedures to unclog arteries with expandable stents and balloons ("angioplasty") save lives in emergencies and need to be used more in that setting. But the plumbing analogy fails when applied to stable, partial blockages that don't lead to sudden heart attacks. And yet doctors can't let go of the plumbing talk, and they keep unclogging partial blockages. That's why the vast majority of angioplasties are done for the wrong reasons--that is, for prevention, not acute treatment.

Metaphors are incredibly seductive: they effortlessly slot into the brain, allowing us to make quick sense of difficult ideas. But we should heed Nietzsche's warning, and always remember that metaphors illuminate as they conceal. If, as Nietzsche put it, our truth is a "mobile army of metaphors," then it isn't true. Beware of theories that lean too heavily on analogies.

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perhaps because we know so little about the mind<\i>

We know very little about unicorns. I'm sure there's a metaphor lurking in there somewhere.

Is this thing on?

You probably know the book "Turing's Man" by J David Bolter, but just in case you don't, it surveys the metaphors used throughout western history to describe the mind.

For Plato, the mind was like a spindle used for making thread, or in other writing an erasable wax tablet. For Descartes, it was like a water clock. Bolter's essential thesis is that the mind (or soul) is alwsys conceived in terms of the most advanced technology of the time.

Perhaps it's not always true, but I think Bolter's work is worth checking out.

In our perception of the world, we have impressions of order. We use metaphors to apply some sort of comprehensible meaning to this perception of order. We speculate that there are laws of nature and laws of science and laws of physics, that cause these impressions of an orderly universe. But even this characterization of the "laws of nature" is just a metaphor, comparing our impressions of order to the imposition of legal order. Beyond our simplest tasks of everyday experience and living, almost everything that we think and do is a speculative metaphor regarding some impression of order, the ultimate nature of which, remains hidden, and a mystery.

It is not true that removal of partial blocks in stable persons are not beneficial. There are a large number of persons who experience remarkable relief of effort angina (chest pain during exertion) after angioplasty. A person with critical narrowing, say 95% of a major artery of the heart does benefit by angioplasty in the form of symptom relief. Many a time, one who was not able to do much work on optimal medication, do go back to work. There is definite improvement in quality of life after successful angioplasty in those who are symptomatic despite optimal medical treatment.