Biology Reference
In-Depth Information
test something like faith or the existence of any given supernatural being, because the exis-
tence of either of these phenomena cannot be
disproved
. Science works by testing and dis-
proving questions: there is no conceivable test that can show a supernatural being
does
not
exist. You might feel faith, you might know a higher being exists, but you simply cannot
test either through scientific means. For these reasons, scientific methods can only be applied
to the natural world, which by definition is separate from the supernatural world.
The Law of Parsimony
This concept states that the simplest explanation is the likeliest one. By “simple” we mean
the most logical and least complicated explanation for a given phenomenon or observation. If
you find a skeleton in the woods of Tennessee and infer that the puncture marks you see all
over the bones were caused by the individual's pet alligator when there is no evidence to
suggest (1) the person's identity and (2) they had a pet alligator and (3) the pet alligator
caused the person's demise, then the likelihood of this inference being correct is
very
low.
In addition, this being the state of Tennessee where there are no alligators in the wild (and
probably very few being kept as pets), the most likely and simplest explanation is that the
puncture marks were caused by a dog that scavenged the remains. Parsimony is important
for many steps of science, including hypothesis construction and critical analysis of the
results. Remember the forensic pathologist's old adage, “If you see hoof prints in Texas, think
horses, not zebras.”
The Hypothesis
In science, a
hypothesis
2
is a scientific statement that proposes an explanation about some-
thing in the natural world. The most important part about hypotheses is that they are
designed in such a way that they can be tested and falsified. Statements that cannot be tested
do not meet the criteria for a hypothesis. For example, a statement such as, “the first person to
travel over the Bering Land Bridge to settle in North America did so on June 12, 8023 BCE”
cannot be tested. This statement is way too narrow and there is no test that could show the
exact date that the peopling of the New World commenced. However, a statement such as,
“the peopling of the New World began around 10,000 years ago” can be tested. This state-
ment is more general and radiometric dating methods (which give date ranges) applied to
prehistoric archaeological sites can be used to test this latter hypothesis.
The second criterion for hypotheses, falsification, is important because as scientific knowl-
edge grows, it should be possible to find that previous explanatory statements were not
correct via new discoveries or evidence. If it were not for the falsifying principle, then valid
hypotheses would not be able to replace invalid ones. As Gould sums up, “science advances
primarily by replacement, not by addition” (
1981b
:322; emphasis added). In science we are
trying to obtain valid explanations for different phenomena, and it must be the case that
explanations found to be invalid are not competing with newer explanations in the testing
stage or explanations already shown by the latest evidence to be the most valid. Whether
2
All bolded terms are defined in the glossary at the end of this volume.
