If the reader asks: in the whole
structure of scientific methodology, which part is the most significant? With
no hesitation, my answer is: theoretical prediction must be “refutable by
facts”. A theory that is not refutable by facts has no explanatory power. It
can be said that the subject of all empirical science is to establish certain
refutable statement for prediction. In other words, science does not seek to be
right, nor seek to be wrong; science seeks to be “refutable by facts”.
Potentially refutable by facts but has not been refuted can then be said to
have been confirmed. As aforementioned, to predict the occurrence of a
phenomenon and to explain a phenomenon is the same thing. Prediction refutable
by a phenomenon but has not been so refuted, whereas the occurrence of a
phenomenon confirms the prediction, such phenomenon can then be said to have
been explained. Certainly, a phenomenon can be explained by a number of
theories. I will subsequently touch upon the choice of different theories.
The key here is: the reason why a
theory not refutable by facts has no explanatory power is that such a theory
cannot be empirically tested. A tautology can never be falsified, and since it
can never be falsified, how can it be refuted by facts? A theory refutable by
facts must be capable of being falsified by imagination. A tautology, being
non-falsifiable even by imagination, has no explanatory power. Besides
tautologies, there are four other situations making theories not refutable by
facts, hence destroying the explanatory power of these theories. These are the
contents of Sections 5 and 6 that follow.
Being refutable by facts is
important. If theoretical prediction is refuted by facts, there are only two
choices. The first one is to abandon the theory and look for others; the second
one is to insert conditions to remedy it. But as mentioned when discussing ad hoc theory, such remedy requires
option to be forgone, and such option forgone should not be too much. Refutable
theory that has not been refuted today may not remain so tomorrow – this is the
course of scientific advancement. Not refuted as of today means that the theory
still retains its uses. The most important criterion in valuing a theory lies
in its applicability to explain phenomenon, not in its right or wrong.
Prediction using a sentence or a
statement has to focus on testable or refutable implication. Such implication
is derived from theory. Logically, the rules for implication are simple: if the
occurrence of A implies the occurrence of B (A → B), then the non-occurrence of B implies the
non-occurrence of A (Not B → Not A).
This is the most fundamental test. For instance, if it rains (A), then there
are clouds in the sky (B). It implies: if there are no clouds (Not B), then it
does not rain (Not A). If there are no clouds but it rains, then the hypothesis
that if it rains (A), there are clouds (B) is refuted by facts.
The way to test the implication of a
theory is to provide evidence to the contrary. This is a crucial point. In
testing the implication that if it rains, then there are clouds (A → B), evidence to the contrary that if there are no
clouds, then it does not rain (Not B → Not A)
has to be provided. To test using if it does not rain, then there are no clouds
(Not A → Not B) is a common fallacy (in
logic, such fallacy is termed fallacy of denying the antecedent). The
occurrence of A implies the occurrence of B, but the non-occurrence of A has no
implication whatsoever on B. It is a common misconception to say the
non-occurrence of A implies the non-occurrence of B, with many scholars falling
into this trap. For instance, in economics we assume every individual maximizes
his self-interest (A), therefore under certain constraints, every individual
will work hard (B). Some scholars submit that an individual does not
necessarily maximize his self-interest (Not A), therefore under the same
constraints, an individual will not necessarily work hard (Not B). This is a
fallacy.
In 1946,
an economist called R. A. Lester published an article catching the whole
world’s attention. After investigating the policy of hiring drivers in Boston’s
private transport companies, he declared wrong the renowned “marginal
productivity theory” (the word “marginal” is not important here, but will later
be expounded). According to economic postulate, every private company will
maximize its profit, therefore in hiring drivers for its trucks, the marginal
productivity contribution of every driver will equal his wage (this is one
implication of the “marginal productivity theory”). Lester checked with all the
principals of Boston’s transport companies and found that they neither knew nor
cared what “marginal productivity” was, therefore this theorem was wrong: the
wages of drivers did not equal their marginal productivity contribution. This
fell into the aforementioned misconception that if it does not rain, then there
are no clouds.
I can cite
an interesting (but non-factual) example to illustrate this “A → B, therefore Not A → Not B” fallacy. Let’s say
there were a group of idiots who knew nothing about real-world phenomena. Yet
economists assumed that they all wisely maximized their self-interest. In fact,
these people were all idiots, therefore this assumption was clearly wrong. On
hearing that gasoline station was fun, these idiots all set up their own
gasoline stations. Being idiots, some built their gasoline stations on remote
mountains, some in dense forests, while some others on the sea. With no
highways for vehicles to pass through, how could these gasoline stations
survive? Nonetheless, some idiots in the same group unknowingly built their
gasoline stations along highways. Not long afterward witnessed the survival of
the fittest. Only those stations situating along highways survived. In fact,
the idiots had not had a clue of what they were doing. The economists’
assumption that they knew how to maximize their self-interests was obviously
wrong. Yet the surviving gasoline stations coincided with the postulate of maximization
of self-interest, such behavior was therefore explained. Reasoning that since
the idiots had no idea what they did, gasoline stations would not be built on a
profitable location is fallacious.
Astronomical
science in ancient China was brilliant, having high accuracy in predicting the
timings of eclipses and lunar eclipses. I have not gone into any depth
exploring what this science is all about, but kids in China have heard about
the legend of “heavenly dog swallowing the sun”. Using the postulate of
“heavenly dog” to explain eclipse or lunar eclipse is certainly nonsense, but
if prediction is accurate and not refuted by facts, it might as well be
acceptable. Today’s theories on eclipse and lunar eclipse having replaced those
of ancient times is not because today’s are right while yesterday’s were wrong,
but due to today’s having more generalization to explain other astronomical
phenomena. Perhaps when tomorrow comes, today’s theories could be proven wrong.
Tautology is absolute yet without explanatory power. A theory with explanatory
power could be wrong, but more importantly, it is refutable by facts. No matter
right or wrong, a theory with explanatory power is a useful one. Reasoning that
there is no heavenly dog swallowing the sun, therefore it cannot be used to
predict the occurrence of eclipse is a fallacy. It is paramount to make the
issue crystal-clear.
No comments:
Post a Comment