1. SCIENCE
The aim of this tutorial is to help you learn to identify and evaluate scientific methods and assumptions.

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What is science?
Science rests upon reasoning that moves from observable, measurable facts, usually called data, to testable explanations for these facts. Scientists discover, observe, and collect facts in a systematic manner to explain data relationships. They then link these relationships through explanatory devices such as hypotheses. Modern science has a profound impact on our lives, and because it is so pervasive, we tend to perceive it as the natural method for obtaining knowledge about the world. However, we must recognize and evaluate the assumptions underlying science to ensure what we are learning is accurate and credible.
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3. Assumptions underlying science
Science is the primary way Western culture perceives and interprets reality. However, it is important to keep in mind that science is a system created by humans and, as such, is based on a particular set of assumptions. These assumptions include empiricism, objectivity, materialism, predictability, and unity.
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4. Empiricism, objectivity, materialism, predictability, and unity
Empiricism – Sense experience is the source of truth.
Objectivity – We can study the physical world without bias.
Materialism – Everything in the universe is made up of physical matter.
Predictability – The universe is composed of interconnected causal relationships.
Unity – The universe has an underlying unified dynamic structure.
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5. Limitations of science
Despite its obvious strengths, scientific reasoning has some limitations. Empiricism and the use of sense experience limits science to observable, shared phenomenon. Additionally, the basis of science, the existence of the physical world, cannot be empirically proven. Furthermore, quantum physics challenges the idea that reality is ultimately predictable and material, and that objective observation is even possible.
As critical thinkers, it is important to keep both the strengths and limitations of scientific reasoning in mind.
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The scientific method
The scientific method is the basis for generating scientific knowledge. It involves a series of steps.
Identify the problem.
Develop an initial hypothesis.
Gather additional information and refine the hypothesis.
Test the hypothesis.
Evaluate the hypothesis based on the results of testing or experimentation.
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7. Evaluating a scientific hypothesis
When evaluating a scientific hypothesis, the following criteria are appropriate:
Is it relevant to the problem under investigation?
Is it consistent with well-established theories?
Is it the simplest explanation for the problem?
Does it provide a testable and falsifiable explanation of the problem?
Can it be used to predict the outcome of similar events?
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8. Distinguishing between science and pseudoscience
Pseudoscience is a body of explanations or hypotheses that, in an attempt to gain legitimacy, masquerades as science. Unlike science, which uses systematic observation, reasoning, and testing, pseudoscience is based on emotional appeals, superstition, and rhetoric. Astrology is an example of pseudoscience. Pseudoscience takes advantage of cognitive errors in our thinking, and is often used to persuade people, particularly the young, as a means to gain money or political support.
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Research methodology
Research methodology is a systematic approach to gathering and analyzing information based on established scientific procedures and techniques. One of these methodologies is experimentation. Three common types of experimentation are field experiments, controlled experiments, and single group (pretest-posttest) experiments. These experiments include elements such as independent variables, dependent variables, and confounding variables, and all use experimental material, the group or class of objects or subjects under study.
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10. Evaluating experimental designs
Regardless of which type of experiment design is used, common evaluation criteria can be applied to test the validity of the experiment and its results. Well-designed experiments use the following criteria:
Discrimination – The experiment discriminates between conflicting hypotheses.
Unbiased – The experiment has checks or controls to eliminate both subject and experimenter bias.
Measurement – The measurements used are appropriate and reliable as well as accurate and precise.
Replicable – The experiment can be reproduced by other scientists.
Generality – The experimental results can be generalized to the population under study.
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11. Ethical concerns in science
Although scientific experiments may be well designed and produce significant results, they may be inappropriate due to their violation of moral and ethical principles and guidelines. Ethical considerations of informed consent, rights, and nonmaleficance (no harm) are particularly important when dealing with human subjects. During the Second World War, Nazi doctors performed unethical experiments on Jews, prisoners of war, and other prisoners. These activities have also occurred in the United States, such as in the Tuskegee Study.
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12. Thomas Kuhn and scientific paradigms
In his work The Structure of Scientific Revolutions (1962), American physicist and historian of science Thomas Kuhn ( ) challenged the idea that science is progressive and objective. Instead he argued that science, like other human enterprises, is a social construct – a product of its society. As such, it is biased by social expectations and professional norms that determine what is acceptable in terms of hypotheses and experimentation.
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13. Scientific revolutions and paradigm shifts
Kuhn argued in favor of three key concepts: normal science, paradigms, and scientific revolutions. Normal science refers to “research based upon one or more past achievements,” while paradigms, building on normal science, provide an accepted view of the world. A scientific revolution, or paradigm shift, occurs when a new scientific theory is developed to replace a problematic paradigm. Einstein’s theory of relativity is an example of a paradigm shift.
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Conclusions
Science and scientific thinking has generated enormous benefit to humanity. However, as critical thinkers we must be aware of its limitations, the temptations of pseudoscience, and the possibilities of other explanations for phenomena. We must use evaluative criteria when considering scientific reasoning, and recognize that new ideas may hold answers to questions that existing paradigms cannot resolve.
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