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Commentary:
Some cling to the old thinking: "If you can't see it and you can't smell it, then what's the problem?"
Or, because many practices have become, as we study here, monopolies and pervasive in our daily lives, the tendency is to think of these things as not harmful.
However, to accept practices just because they have been around for 20, 30 or even 100 years, without appropriate scrutiny, is to repeat the mistakes of the past. |
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Module 1, Lesson 1:
Uncertainty in Science
Wisdom is to know, that you do not know."
-Socrates
"Scientific Uncertainty" usually means any area of science where there are gaps in knowledge or the lack of conclusive, cause and effect proof.
However, for purposes of this instruction, we will use three classifications of scientific uncertainty defined by the European Environmental Agency 1 to help refine our discussions about the purpose of the precautionary principle.
- "Risk"
- "Uncertainty"
- "Ignorance"
- Risk - "Known impacts and Known probabilities" - Example:
Benzene exposure and leukemia.
Most often, risk associated with an individual chemical is assessed by the process of risk assessment. Risk assessment uses the toxicological profile of a chemical and uses mathematic probability calculations. This is the classification with which we are most familiar.
Uncertainty -"Known impacts and Unknown probabilities" - Example: Mercury's ability to interfere with development (known impact) and rising incidence of learning disabilities in children (unknown probability).
Uncertainty is a broad term, but here we specifically use it to mean situations where risk calculations generally will not hold up in real world conditions. This would be where there is no basis to assign probablilites. This is generally true due to the complexity of systems.
For instance, we know that some plastic containers can leach chemicals, such as nonylphenol, that have estrogenic* effect. We know that breast cancer cells can proliferate in these plastic containers.2 What then is the probability that this type of daily exposure from xenoestrogens* promotes breast cancer? This is uncertainty.
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- Ignorance - "Unknown impacts and Unknown probabilities" - Example: Chlorofluorocarbons (CFCs) and the ozone hole before the mid-1970s. Scientific ignorance is by far the most challenging of scientific uncertainty. We simply do not know what we do not know. We cannot anticipate what we would have never of thought of as possibilities in the first place! CFCs depleting the ozone layer was something that would have been never thought of, much less, considered.
Historically, in case after case, the lack of certainty in science has led to failure to act because of the demand for conclusive evidence of cause and effect. Even when warning signs were very prominent, our pattern has been to call for more studies.
From 1897, we had some evidence that benzene caused aplastic anemia and was a bone marrow poison. Seventy years later, when workers were suffering from benzene-induced leukemia, action was once again delayed and what ensued was an intense period of study. Since the 1960s, more than 11,000 studies on benzene are recorded in National Institutes of Health's database!3
Once a chemical is implicated in serious health effects, it is often well dispersed into the environment or in products commonly used by consumers.
These chemical products are used so much that they create their own "monopolies." Their discontinued use or ban is very difficult and costly to society. Some examples of chemicals that became monopolies include CFCs; PCB's; Asbestos; DDT; and Chlordane. |
1 Late lessons from early warnings: the precautionary prinicple 1896-2000, p 170.
2 Soto and Sonnenschein's work at Tufts Medical School in Boston. Recounted in Our Stolen Future, Chapter 8, pp 122-141
3 See chart on catastrophies that led to intense scientific study, Body Burden: Pollution in People
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