contact@onbelief.orgBelief Tests in Engineering
Uncertainty in applied science is not restricted to medicine (as discussed previously). Similarly professional judgment is essential in many other situations where very complex beliefs are formulated but where a complete technical description of the problem at hand is not possible.
Engineering is a very important area of 'natural philosophy' where the 'beliefs' of its practitioners affect our everyday lives in ways that most people take for granted and possibly have never even thought about. ( Indeed it has got to the ridiculous stage where many people would not even know the difference between a professional engineer and a washing machine repair technician.) Although we have all come to rely very heavily on the activities of all sorts of professional engineers we should consider that uncertainty of belief and its philosophical ramifications in engineering are also important.
An Engineering Example: Soil Mechanics
In very complex engineering situations such as that faced by the geotechnical engineer for example assumptions need to be made and decisions need to be arrived at about how to proceed with a construction in the face of incomplete or even unknowable data. The geotechnical engineer, for example, might have to be concerned with problems such as as earthquakes, landslides, slope stability and soil liquefaction, all of which in reality are often unknowable quantities. Any test borings of the subsurface and soil samplings that the engineer requires to help her make estimates will need to be based on beliefs about the correct places to sample. She will then need to make assumptions about the behaviour of a complex soil mixture based on these samples.
Geotechnical engineers need to have a 'strength of belief' associated with the mathematical models (or formulae) that are currently in vogue to explain how complex soils behave in particular circumstances and under construction loadings. The engineer will have had to consider in what ways the currently accepted methods of describing soil characteristics and arriving at parametric values in soil mechanics apply in the circumstances they face. They will therefore have some 'degree of belief' in the utility or value of measuring such quantities such as Unit Weight, Porosity, Permeability, Consolidation, Shear strength, and Plasticity of soil.
In plain terms, assumptions (i.e. beliefs not based on definitive evidence), are essential. When disaster strikes it is to be hoped that the engineer will then revise her very complex belief system about what is important in the light of new evidence or principles of analysis.
Read: an engineer's response
Further Reading: Degrees of Belief. Subjective Probability and Engineering Judgment (2002), Steven G.Vick, American Society of Civil Engineers Press
On the Nature of Belief
www.onbelief.org
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