Friday, April 18, 2008

The Immunologist - slave to discontinuous thinking

Everyone's favourite militant atheist Richard Dawkins talked about the "tyranny of the discontinuous mind" in his book The Ancestor's Tale. This concept involves the natural tendency of us, as feeble humans, to try to divide everything into categories. We try to place all that we see as this or that, but never something in between. Or rather, when we do, the something in between becomes a new category, and not just a statement of the continuum between. Often you can find statements that prove this point.

"There are three types of phenomenon X:
a) extreme A
b) extreme B
c) some combination of the two "

Instead of setting up anything so stupid, all we need to say is that X falls between A and B, and ignore all the silliness of that list. However, our natural tendency is to try to divide continuous phenomena into groups of some sort or other. Reality gets forgotten and replaced with a model that categorizes whatever phenomenon we're talking about. This is the gist of the argument Dawkins presents, along with ample evidence of why it can suck.

I've seen first hand how this method of thinking can really harm the scientific process, at least the teaching of it. While In Dawkins' book he used ring species as the example of the limits of this method of thinking in phylogenetics, I have seen it in the context of immunology. This science is still working through its growing pains, still newborn with respect to its old-timer colleagues microbiology, cell biology, and chemistry. But in addition to that, it is a unique science in that the discontinuous, reductionist model no longer applies very well. There are specific instances where in vitro models have been helpful, but the science as a whole suffers from a lack of simplification usually possible in other subjects, that build from the ground up.

Immunologists classically try to break down all aspects of the immune response into discrete categories, but unfortunately, the harder you look, the more often you find that those distinctions are really just fuzzy boundaries, if not just two extremes of an continuum. I ran into trouble when trying to divide up cell lineages at one point because everywhere you try to define a complete group, you find that there is an exception. And in each of those exception groups, there is an exception to the exception. Big fleas have little fleas and so on. This tells me that maybe we're going about this the wrong way. A real revamp of how we look at this system is in order.

This isn't to say that divisions shouldn't be made, but they should never be presented as absolute divisions, as many the instructor seems wont to do. As soon as you start saying "This pathway applies here unless A of B or C or D happens", you're just asking to be proven wrong once E shows up to wreck your day. Its better to explain more of how the pathway actually works, and so predictions can be made. You can say, well based on what I know, if E happens, then I can expect this result. Take that, E.

Immunologists, take note. You're not going to get anywhere until you drop the reductionism and gain a better appreciation of (or respect for) the system you're dealing with. In fact, scientists in general should check themselves for this from time to time. Its all too easy to get caught in a cycle constantly breaking things down into groups until you reach a point where the groups themselves lose all meaning. This is the discontinuous mind at work, and in this case working against you.

The next time a biologist tells you that something falls into one of several categories, tell them they're lying. I dare you. No, double-dog dare you. Given enough time, you'll be proven right. You'll thank me. And to express your gratitude, you know where to send the cheque.

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