Biology Reference
In-Depth Information
or not a hypothesis is falsified depends on the level of surety that you set with the test (often
with the statistics chosen) and the critical analysis of the results. It is important to note that
your results and thus your determination of falsifiability will not always be cut and dry.
There are often gray areas where the results are inconclusive
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which may indicate that
you need to refine your hypothesis and/or your testing mechanism.
For example, a prevailing hypothesis that stood for centuries in the Western world was that
the Earth was flat. This hypothesis was of course falsified when sea journeys began in earnest
by European nations in the fifteenth and sixteenth centuries and the ships did not fall off the
edge of the Earth. The new evidence of ships continuing to sail past the horizon without falling
in part resulted in the replacement of the earlier hypothesis of the Earth being flat.
In addition, the very nature of science is that while we
can
show that a hypothesis is not
always true, we
cannot
show that one is always true, because there might be some future test
or evidence that could refute current knowledge and results. This is reflected in the language
we use when analyzing the results
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we either reject or fail to reject the hypothesis. A simpler
way to think about this is that we can either state the hypothesis has been supported by the
results, or that it has not been supported by the results. Refer to the hypothesis testing section
later in this chapter for more detailed information about hypotheses.
Fact and Theory
Facts are essentially the world's data (
Gould, 1981a
): vertebrates have skeletal systems,
most mammals give birth to live young, and humans need to breathe oxygen to survive
are all examples. A theory results from a number of related hypotheses that have been tested
and retested and not shown to be untrue (
Gould, 1981a
). Facts and theories differ because
while facts are always true (all vertebrate animals have skeletal systems), theories have
been shown to
not be false
, based on the preponderance of the existing evidence. Theories
are therefore explanations, verified over time, that are based on many consistent observations
from different and various experiments.
Note that this definition of “theory” is very different from the way we use the word in
everyday language. The general public would define “theory” as meaning “guess.” In science,
a theory is not a guess. The Germ Theory of Disease is a valid explanation for what causes
disease, not mere conjecture. Similarly, the Theory of Evolution is also a sound explanation
for species change, not speculation. These theories came into existence after the testing and
retesting of a variety of different hypotheses showing (1) the explanations were the simplest
ones for the phenomenon, (2) the explanations made predictions that could be tested, and (3)
the explanations had not been shown to be untrue (
Graziano and Raulin, 2000
). These two
theories have stood the test of time because the vast accumulation of evidence has continued
to support them and because they still meet the three criteria for a theory listed above.
We have entered into the preceding discussion about science versus religious belief and
hypothesis versus theory because as an anthropologist, it is quite likely that you will be
tasked with teaching the basics of science at some point in your career
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and it is absolutely
essential that you first, fully understand the principles, and second, are able to talk about it in
a convincing and understandable way. There is no greater misunderstanding with regard to
scientific principles among the general public than the points of what a scientific theory is
and what science can and cannot do.
