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Lecture slides summary Engineering and design science methodologies (2016TEWMHB)
- Instelling
- Universiteit Antwerpen (UA)
Summary of lecture slides with personal notes. I got 17/20 for the exam.
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ENGINEERING AND DESIGN SCIENCE METHODOLOGIESLECTURE A1: ON SCIENCE AND PARADIGMS
On the basics of science and the scientific method, and the pitfalls of self-fulfilling models and rusted paradigms.
The Scientific (Empirical) Method
The method includes following steps:
1. Observe a phenomenon
2. Find patterns in observations
3. Develop fitting descriptions and/or equations: these will be called models or hypotheses
4. Conduct experiments to verify to what extent the models are able to predict future observations
5. If the model/hypothesis predicts multiple observations successfully, it will become a law or scientific theory
On the Characteristics of Models
• Models are a description, a simplification of reality
o Example: Price of car is proportional to weight of car → These sentences describe reality in simplified way → They
are models.
• Fundamental laws describe, do not explain reality
• Appeal preferably to intuition (Human can use these models in best possible ways)
• As simple as possible, i.e., Ockham’s razor
o Example: Fit model to data, but no overfitting (Simple model can be generalized in better way than complex models)
→ Law of Ockham
• Need to remain stable with respect to new data
• Are in general valid within certain boundaries
• Should be able to predict future observations, both through extrapolation and interpolation (e.g. Observe a car → predict
price)
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, • Models are never a perfect representation of reality
o Having exceptions and deviations
o Valid within certain boundaries
▪ Exceptions: Sport cars will be less heavy and more expensive than heavy SUV
▪ Deviations: Measuring points always situated within certain limited range → large deviations can occur
while extending the range (e.g. Weight of car exceeds certain threshold → price increase more than
proportionally with its weight)
→ The proposed model is only valid below a certain maximal weight (Valid within certain boundaries)
On Laws of Nature
• Are fundamental models
o They describe and do not explain
• Very thoroughly tested
o Can be (partially) falsified, never fully verified
• Are only valid within certain boundaries
o Newton’s Gravitation Law → General Relativity Theory
• Can be superseded by ‘better’ models that
o provide more accurate predictions
o remain valid in a broader range or scope
• Are essentially differential equations
Some Laws of Nature
• Newton’s Law
o F = m.a
o Gravitation Law
• Electricity
o Ohm’s Law
o Coulomb’s Law
• Chemistry
o Mass conversation
o Energy conservation
Some Philosophy of Science
• Scientific explanation and prediction
~ empirical verification
• Problem of induction → engineering
• Ockham’s razor: simplest solution
• Theory and observation
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, ~ Thomas Kuhn: paradigms
• Demarcation problem
~ Karl Popper: falsifiability
Some Philosophy of Science – Additional
Self-fulfilling models and paradigms
• Not to be confused with self-fulfilling prophecy
o Self-fulfilling prophecy: process through which an originally false expectation leads to its own confirmation. In a self-
fulfilling prophecy, an individual's expectations about another person or entity eventually result in the other person
or entity acting in ways that confirm the expectation
• The model or paradigm is implicitly treated as axiomatic or irrefutable
o New concepts are introduced to accommodate the “strange observations”
• Empirical observations are “merged” with the undisputed model
o By rephrasing observations and causal mechanisms
o By postulating fictitious alternate outcomes based on model causality
▪ E.g., “it would have been …”
On Self-Fulfilling Models: The Diffusion Force
• Force causes change
• Change caused by force
→ Diffusion force (Force causes change. In case change occurs without force, a so-called diffusion force is introduced)
Brownian Motion
(More from the right to left → equilibrium)
(The driving force for diffusion is the thermal motion of molecules)
On Self-Fulfilling Models: The E = mc2 Equivalence
• Law of Mass Conservation
• Law of Energy Conservation
→ Mass and energy are equivalent
Self-fulfilling models and paradigms
• Self-fulfilling models are not necessarily bad, as they may offer a consistent and coherent way of describing natural
phenomena Such a consistent framework is often called a paradigm
• One needs to be aware of such an underlying paradigm
• One needs to be alert when paradigms create complexity
• Such paradigms should not be used to confirm implicit assumptions, which may work as a seeding mechanism for dogmatism
Thomas Kuhn: Structure of Scientific Revolutions
• As a paradigm is stretched to its limits, anomalies — failures of the current paradigm to take into account observed
phenomena - accumulate. Their significance is judged by the practitioners of the discipline.
• In any community of scientists, Kuhn states, there are some individuals who are bolder than most. These scientists, judging
that a crisis exists, embark on what Thomas Kuhn calls revolutionary science, exploring alternatives to long-held, obvious-
seeming assumptions. Occasionally this generates a rival to the established framework of thought. The new candidate
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, paradigm will appear to be accompanied by numerous anomalies, partly because it is still so new and incomplete. The
majority of the scientific community will oppose any conceptual change, and, Kuhn emphasizes, so they should.
• The Ptolemaic approach of using cycles and epicycles was becoming strained: there seemed to be no end to the mushrooming
growth in complexity required to account for the observable phenomena. Johannes Kepler was the first person to abandon
the tools of the Ptolemaic paradigm. He started to explore the possibility that the planet Mars might have an elliptical orbit
rather than a circular one.
• Their achievement was sufficiently unprecedented to attract an enduring group of adherents away from competing modes
of scientific activity. Simultaneously, it was sufficiently open ended to leave all sorts of problems for the redefined group of
practitioners to resolve. Achievements that share these two characteristics, I shall refer to as "paradigms".
On Scientific Revolutions: Past AND Future
• 450 years ago people and "leading experts" said that the earth was flat.
• Progress is made by proving renowned experts and scientists wrong.
• This did not end 450 years ago.
• It seems highly unlikely that, for the first time in our long human history, there would be no major flaws in 21st century
science.
Karl Popper: Science is based on falsifiability
• Popper argued that science should adopt a methodology based on falsifiability, because no number of experiments can ever
prove a theory, but a reproducible experiment or observation can refute one.
• Falsifiability is a deductive standard, and does not leave much room for induction, e.g., the case of black swans.
• Often considered as the demarcation between science and anti-science.
On Self-Fulfilling Models: The Policy Pitfall
• The casual use of self-fulfilling models is tempting and highly dangerous for causal relationships that are not yet supported
by evidence. Example:
o More stringent lockdowns→→ less infections and deaths
o Mandatory mouth masks less infections and deaths
o ….
• It is even more dangerous to base policies on such premises, as conflicting empirical data will be leveraged to the contrary:
o It would have been worse otherwise, we need to be tougher!
• Being adopted by policy and media, the models can turn into paradigms, resulting in dogmatic reinforcement by the
(scientific) establishment
On the Current Scientific Environment
• Universities operate within a business model context not completely aligned with questioning paradigms and pursuing
falsifiability
• Researchers need funding grants
o From big corporations having often business interests
o From government agencies having often political interests
• Researchers need paper acceptances
o From reviewers working in this funding environment
o From editors representing the current prevailing paradigms
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