William of Ockham was an English
Franciscan friar, scholastic philosopher, and theologian from 1287 to 1347
ad. He did not invent the principle for
which he is famous (Ocham’s razor), but he is famous for his use of it. While he worded the principle different ways
in different writings, his most famous quote is "Entities are not to be
multiplied without necessity". In
other words, keep things as simple as possible.
Aristotle (384–322 BC) is credited with the earliest use of this
principle writing in his Posterior Analytics, "We may assume the
superiority ceteris paribus [other things being equal] of the demonstration
which derives from fewer postulates or hypotheses.” In other words, all things being equal the
simplest explanation is the best and the most likely to be true. Wikipedia defines today’s usage as “the
problem-solving principle that, when presented with competing hypothetical
answers to a problem, one should select the one that makes the fewest
assumptions.”
Dr. Theodore Woodward, professor at
the University Of Maryland School Of Medicine, gave the most famous example of
this principle in action when he applied it to medicine in the late 1940s. The problem with allowing doctors in training
to diagnose patients is they tend to pick the exotic possibilities. Given the options of necrotic skin lesion or
recluse spider bite most students will pick recluse spider bite even in areas
where no recluse spiders are known to exist.
To combat this tendency Dr Woodward coined the memorable expression that
became known as the zebra.
You are walking past crowded horse
stables in rural Maryland. You hear hoof
steps behind you. Without turning
around, are those hoof steps from a horse or a zebra? Horses are known to reside in these
stables. Perhaps you have seen
them. Perhaps you work at the
stable. Or perhaps there was a break out
at the zoo hundreds of miles away and a zebra got loose. Or maybe there lives an eccentric billionaire
who bought an exotic animal for his granddaughter and flew it all the way from Africa
and it somehow managed to jump a twenty foot brick wall, evade the security
cameras, run cross country, see the horse food in this stable because it is now
a very hungry escape artist and surprise, there is now a zebra behind you. In a horse stable. In Maryland.
Utilizing Ockham's razor, is that a
horse or a zebra?
Ockham's razor gets a little trickier
when applied to science. While it is
true that it is highly unlikely for there to be a zebra in rural Maryland, it
is not entirely impossible. Along these
lines of thinking, philosopher of science Karl Popper created a scientific alternative
referred to as "falsificationism".
“A statement, hypothesis, or theory
has falsifiability or refutability if there is the possibility of showing it to
be false. It is falsifiable if it is possible to conceive an empirical
observation or a logical argument which could refute it.” (Wikipedia)
Popper also stresses the problem of
distinguishing the scientific from the unscientific and makes falsifiability
the deciding factor. Using these
criteria, what is unfalsifiable is classified as unscientific, and the practice
of declaring an unfalsifiable theory to be scientifically true is
pseudoscience.
You could make the statement that
there are only horses in Maryland and no zebra could ever possibly set foot
within its borders. You could then line up
hundreds of thousands of horses in Maryland to prove your statement to be true. But if someone finds just one zebra your
statement is now false. The ability to
prove this statement to be false makes it falsifiable or refutable and thus a
valid scientific statement simply because it can be tested.
However, if you were to say that there
is a zebra hiding in Maryland that statement cannot be proven false. No matter how many horses you find there
remains the possibility that somewhere in the borders of Maryland there hides a
zebra. This statement cannot be tested
because it cannot be disproven. Because it cannot possibly be disproven it is unscientific; it is pseudoscience.
If something can be proven false it can be
tested. If it can be tested than it is
scientific. If something cannot be
proven false than it cannot be tested. If
it cannot be tested than it is not scientific.
According to Paly’s watch, we can
prove the existence of a creator God if we can find evidence of intelligent
design in creation. According to Dr
Popper this method is scientific because a lack of design would prove a creator
God to be a false hypothesis. If intelligent
design is evident in creation we can use Ockham’s razor to decide if other
possible explanations are more or less likely than the possibility of a creator
God. If the other possibilities cannot
be proven false than they are pseudoscience and should be discarded.
further reading:
wikipedia: Ockam's Razor
wikipedia: Falsifiability
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