Science as a way of knowing  (Page 4/8)

In addition, as shown in ( [link] ), you can see that just as observations lead to predictive hypotheses , theories can lead to predictive hypotheses as well. In fact, one of the hallmarks of a theory is that it provides a solid framework for generating hypotheses and making predictions. Scientists are confident in the explanatory power of theories, and thus are comfortable in using them to construct hypotheses, design experiments, and frame the interpretation of the data generated by those experiments. Just as a scientific hypothesis is useless if it cannot generate predictive hypotheses, a theory must serve as a framework for hypothesis building and testing. And just as the predictions of the hypothesis must be borne out by new observations if the hypothesis is going to be accepted, predictions from a theory must be supported by the observations if the theory is to continue to serve as the best available explanation for a vast set of observations.

Not shown in that figure, but implied nonetheless, is the fact that the observations must be repeatable. Other scientists, working in other locations, need to be able to do similar experiments and get the same results. That is what is meant by the statement that science is objective, not subjective. Another scientist has to be able to get the same results as you, and vice versa. Again, the history of science has thousands of examples where a new and exciting result was announced, but eventually forgotten when other scientists could not get the same result. Recent ones include the phenomenon known as “cold fusion”, or the identification of a virus that was thought to cause Chronic Fatigue Syndrome (CFS). In all of these cases the original observation was found to be flawed in some way, and subsequent work, either by the original observers or by others, revealed the flaws and debunked the explanation.

Finally, it is important to remember that all scientific conclusions are provisional. In other words, a scientific conclusion is accepted as the current best explanation, but with the understanding that future investigators could make observations that might negate or modify the conclusion. So it is likely that some of the things that you will learn in this class are wrong, or at least incomplete. We still expect you to learn them, since they are the current best explanation, but it is almost certain that something in this textbook, or in the other materials for this course, will be shown by future scientists to be erroneous or incomplete. Who knows, you might be the scientist who does the work that reveals the error. Scientists actually dream about being the person who overturns a long-established notion, since that often means that their work will be remembered, and may even appear in future biology textbooks. One example of overturning a long-established concept, and ensuring a place in future textbooks, can be found in Louis Pasteur’s experiments, described below

Experiments and controls

As mentioned above, a common approach to generate new scientific knowledge is to perform experiments, where the scientist changes the situation and then observes the effects of these changes. In keeping with the scientific method, this starts with an observation, from which the scientist generates a hypothesis. The hypothesis leads to a testable prediction, followed by experiments based on that testable prediction. Let’s look at one of the most famous experiments in all of biology as an example.