In Defense of Blue Fairies

"We are all aware, although we rarely think about it, that all human forethought depends on our recognizing or putting some kind of order into the world. As much as bookkeeping, government, and doing the weekend shopping,... science is an activity of putting order into our experience... Science is to get rid of angels, blue fairies, and other agents whose intervention would reduce the explanation of physical events to other than physical terms... We must use science as it is, and that is an assembly of observations so ordered that they tell us what we may expect in the future. Science is not only rational; it is also empirical. Science is experiment, that is orderly and reasoned activity. The essence of experiment and of all science is, that it is active. It does not watch the world, it tackles it."
Bronowski J. (1950, 1978), The Common Sense of Science, Chap. 7, Cambridge MA: Harvard UP

Bronowoski rejects the notion that science might attribute a treatment effect to the beneficence of blue fairies. This rejection of myth is central to the "modern" science of Galileo, Descartes, Newton and Karl Marx. But the attitude is at odds with the postmodern world. If there is no room for blue fairies in Rasch measurement, then Rasch measurement may already be obsolescent.

The Table contrasts modern, materialistic, deterministic thinking with postmodern, allegorical, indefinite thinking. In modern science, metaphor has no place because scientists say what they mean. They do not say one thing yet mean another. But metaphor permeates thinking and language. Everything is expressed as something, and subtle differences in what "as" connotes make the same thing mean different things from scientist to scientist and society to society. To one group, an apple is a source of nutrition, to another "the knowledge of good and evil."

Western science, with its utilitarian logic and technology, is efficient at "conquering" nature. But, in conquering nature this way, we lose ourselves. Other, more "primitive", cultures seem to have more effective ways of integrating themselves into their ecologies.

For the premodern person, blue fairies were commonplace, but modernity took them away. They are not observer-independent, replicable manifestations. They are not scientific. But now philosophers have discovered that, strictly speaking, there are no scientific facts. No fact is independent of its observer. The observer contributes to the fact. Postmodern has brought blue fairies back.

The myth of blue fairies is a minuscule part of what the observer brings to the search for "facts". Blue fairies are incorporated into every "fact" discovered. Facts are facts, just as they always were, but we play a part in their lives, and not just they in ours.

It is good to admit that blue fairies have a place in our lives because knowing how to treat blue fairies right is an important part of knowing how to treat Nature right. Blue fairies may only inhabit our imaginations, but they enable us to think otherwise unthinkable thoughts. I hope we haven't ruined the blue fairy habitat and driven them to extinction, for then we will be lost.

Inherently perfect science sees Nature as imperfect, eroded by entropy Inherently imperfect science accepts chaotic Nature as its own creation
Nature is controlled or exterminated Nature is encouraged and enjoyed
The one truth of Nature awaits discovery by scientists Scientists construct the data they want. Interpretation of Nature depends on the scientist
Science searches for truth - excludes metaphor, myth, personality Science works with multivalent meaning, expressed in metaphor, myth and personality
Unambiguous data are observed through instruments that do not alter Nature Ambiguous, stochastic data are constructed to inform theory via instruments that alter Nature
Data are truths to be accepted Data are chosen and edited to construct meaning
Cold, hard, observer-independent data are explained by fortuitous description Warm, soft, observer-dependent probabilities nourish models of prescription

William P. Fisher, Jr.

In defense of blue fairies. Fisher WP Jr. Rasch Measurement Transactions 1993 7:3 p.306

In defense of blue fairies. Fisher WP Jr. … Rasch Measurement Transactions, 1993, 7:3 p.306

Rasch Publications
Rasch Measurement Transactions (free, online) Rasch Measurement research papers (free, online) Probabilistic Models for Some Intelligence and Attainment Tests, Georg Rasch Applying the Rasch Model 3rd. Ed., Bond & Fox Best Test Design, Wright & Stone
Rating Scale Analysis, Wright & Masters Introduction to Rasch Measurement, E. Smith & R. Smith Introduction to Many-Facet Rasch Measurement, Thomas Eckes Invariant Measurement: Using Rasch Models in the Social, Behavioral, and Health Sciences, George Engelhard, Jr. Statistical Analyses for Language Testers, Rita Green
Rasch Models: Foundations, Recent Developments, and Applications, Fischer & Molenaar Journal of Applied Measurement Rasch models for measurement, David Andrich Constructing Measures, Mark Wilson Rasch Analysis in the Human Sciences, Boone, Stave, Yale
in Spanish: Análisis de Rasch para todos, Agustín Tristán Mediciones, Posicionamientos y Diagnósticos Competitivos, Juan Ramón Oreja Rodríguez

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