discovered something unexpected and exciting, but were disappointed to find
that your grade was lowered because you were unable to prove your initial
hypothesis, and so failed to faithfully follow the ‘‘scientific method.’’ Such
incidents are all too common in science education, and are all the more unfortunate
because, in truth, the actual practice of science is anything but methodical,
being rather fairly chaotic. The ‘‘scientific method’’ is the recipe from which we
can make sense of this chaos, choosing hypotheses that will be kept as ‘‘theories,’’
and discarding those that are inconsistent with Nature.
This recipe, however, also raises many questions. For example, how are
hypotheses concocted? How do we select among competing hypotheses? How
do we obtain predictions from the hypothesis? What if a hypothesis explains the
initial data but has no predictions? I will deal with these issues below.
Paradigms
When studying a part of Nature the observer does so with a certain set of loose
preconceived ideas, a certain amount of background knowledge that he/she uses
to make sense of the observations. This is often called a paradigm. This background
knowledge can range from the very basic (e.g. far-away things look
smaller) to the complex (e.g. the propagation of light in matter is determined by
the interaction of light with subatomic particles). Using this background knowledge,
the observer attempts an explanation of the phenomena and produces a
hypothesis. It is important to note that this hypothesis, though created within the
context of a certain body of knowledge, need not agree with that knowledge.
Thus Einstein studied the properties of light using Newton’s ideas of motion, but
the hypotheses that flourished into the Special Theory of Relativity disagreed
with Newton’s basic assumptions about space and time, which were almost
universally accepted as providing the basic description of the workings of
Nature; Harvey obtained his revolutionary description of blood circulation
only after careful anatomical observations motivated by Galen’s ideas, etc.