| If
you were to measure 20 carrots, and found that they were
all between six and eight inches long, you might conclude
that all carrots were in that size range. The
manner of logic you used to draw your conclusion is called
inductive reasoning. According to the philosopher
John Stuart Mill, its chief proponent, we are using
inductive reasoning when we conclude "that what is
true of certain individuals of a class, is true of
the whole class, or what is true at a certain time
will be true in similar circumstances at all times."
He argued that this logic is possible
because there is a certain "uniformity" in
nature which allows for such conclusions to be made. The
classical example used to illustrate inductive reasoning
is the "fact" that all human beings are
mortal. To prove this "fact," however, all
human beings would have to be dead already. Obviously,
some of us are still around! How can we be sure that one
of us won't live forever? We can't. However, through
inductive reasoning, we can conclude that there is an
extremely high probability that all human beings
are mortal.
Many scientific "laws" are a
result of inductive reasoning – even though it is, a
matter of probability. Astronomer Johannes Kepler, for
instance, noted the position of the planet Mars during
several points of its orbit. Working on the assumption
that natural orbits maintain a uniform geometry, he
induced that the orbit had to be in the shape of an
ellipse. In fact, if you were to actually calculate the
planet's position during ALL of the points of its orbit,
it would, in fact, trace an almost perfect ellipse. No one
has ever discovered a planet that didn't follow his
principle, which has become known as "Kepler's
Law" of planetary orbit.
No one has discovered an exception so
far, that is. As the study of the universe expands, we
cannot know with certainty what we will encounter. Other
scientific "facts," drawn from inductive logic,
have crumbled as a new piece of evidence was found. The
weakness with inductive reasoning, then, is that it relies
on partial knowledge to draw conclusions about
"truth." In the case of medical science, this
weakness can be harmful, if not tragic. When medical
researchers draw their conclusions on what is right for
ALL people based on what they have observed to be right
for SOME people, they run the risk of doing irreparable
harm to many people.
|
Take
the example of appendectomies. Medical doctors had studied
this curious organ for a long time and had never found a
useful purpose for it. They concluded therefore, that it had
no useful purpose. When it became inflamed or otherwise
troublesome, they removed it. It took years for the
medical profession to admit that its reasoning was
incorrect, and to seek other means of treating
appendicitis.
Medical science still stands by most of
its other conclusions, however, even though they were
arrived at by the same reliance on inductive reasoning.
Moreover, it adheres to the "rules" with a
rigidity that often does not allow for individual
differences. Scientists discovered that the average
temperature for a human being is 98.6 degrees Fahrenheit.
If you have a 99.3 degree temperature, you're said to be
"running a fever" and you're given medications
to bring the temperature back to "normal."
The problem with this type of reasoning
is obvious. No one perfectly fits the profile of the
"average" human being – not in height, weight,
or even body temperature. It is incorrect to conclude that
the correct temperature for all members of the human race
is the same as the "average" temperature of a
sample of individual members.
Long ago, clothing manufacturers
realized that all people are different. They would love it
if all size people were exactly the same. They wouldn't
have to produce a size 12 petite as well as a size 12
tall, medium, and large. Even so, it seems impossible at
times to find something that fits right! The only way to
get a really good fit is to have the item custom-made.
If you go to a tailor and order a new
outfit, someone takes your exact measurements. Can you
imagine the tailor saying, "The average human being
is 5'7" tall, 180 pounds, with a 34" inseam.
I'll use those measurements to make your wardrobe?"
You would, no doubt, look for a new tailor.
Yet, because of the total reliance on
inductive reasoning, science – particularly medical
science – uses "off-the-rack" diagnoses,
remedies, and medications. They routinely begin to stitch
a wardrobe together using only "average"
measurements. Is it any wonder, then, that their suits
seldom fit right? |