Opposing
to inductive logic as the methodology of science, Karl Popper proposes the
theory of the deductive method of testing. In his book “The Logic of Scientific Discovery”, he argues that scientific hypothesis should be empirically
tested and falsified in cases. It is easy to test the validity of a chain of
logical reasoning. Just break it up into many small steps, each easy to check
by anybody who has learnt the mathematical or logical technique of transforming
sentences.
Falsifiability as essence
of science
Popper
argues that what distinguishes the empirical science from pseudo-science is
that the former theory intrinsically falsifiability.
“I shall certainly admit a system as empirical or scientific only if
it is capable of being tested by experience. These considerations suggest that
not the verifiability but the falsifiability of a system is to be taken as a
criterion of demarcation. In other words: I shall not require of a scientific
system that it shall be capable of being singled out, once and for all, in a
positive sense; but I shall require that its logical form shall be such that it
can be singled out, by means of empirical tests, in a negative sense: it must
be possible for an empirical scientific system to be refuted by experience.”(18)
The
reason why he emphasizes falsifiability, not verifiability, is that it is not
possible to prove something in empirical science. Through the history, every
scientific theory has been denied by the new facts and then updated. Popper
took a radical example to explain his idea: “Let us suppose that the sun will not rise tomorrow. Should
such a thing occur, science would have to try to explain it, i.e. to derive it
from laws. Existing theories would not merely have to account for the new state
of affairs: our older experiences would also have to be derivable from them. “(250)
Granted,
the best thing is that we can just jump into immortal truth, but that will not
come true forever. That is why human beings have taken paths that seem to be
beating around the bush.
Probability of hypothesis
and probability of events
Popper
also strictly differentiates probability of hypothesis from probability of
events. He argues that probability of hypothesis should not exist in science,
although probability of events do and contribute for testing the validity of
hypothesis.
Hypotheses
regarding probabilities are not verifiable because they are universal
statements, and they are not strictly falsifiable because they can never be
logically contradicted by any basic statements. (259) I believe that physics
uses probability statements only in the way which I have discussed at length in
connection with the theory of probability; and more particularly that I uses
probability assumptions, just like other hypotheses, as falsifiable statements.
(260)
Science in evolutionary
process
Popper
believes that the essence of science is its falsifiability and thus its
evolutionary process which lasts forever. One driving force of the evolution is
craving for the truth, although the goal will never be attained. Another
driving force is one’s intuition:
although new facts have always transformed science, those facts do not come to
those who passively experience it; it comes to someone who believes in his/her
anticipation, idea, speculative thought and so on. In other words, the facts
that change the world are visible to only those who want to do it.
“Science is not
a system of certain, or well-established, statements; nor is it a system which
steadily advances towards a state of finality. Our science is not knowledge
(episteme): it can never claim to have attained truth, or even a substitute for
it, such as probability.
Yet science has more than mere biological
survival value. Although it can attain neither truth nor probability, the
striving for knowledge and the search for truth are still the strongest motives
of scientific discovery.
Marvelously imaginative and bold conjectures
or “anticipations” of ours are carefully
and soberly controlled by systematic tests. Once put forward, none of our “anticipations” are dogmatically upheld.
Our method of research is not to defend them, in order to prove how right we
were. On the contrary, we try to overthrow them. Using all the weapons of our
logical, mathematical, and technical armoury, we try to prove that our anticipations
were false – in order to
put forward, in their stead, new unjustified and unjustifiable anticipations,
new “rash and premature
prejudices”, as Bacon
derisively called them.
The
advance of science is not due to the fact that more and more perceptual
experiences accumulate in the course of time. Nor is it due to the fact that we
are making ever better use of our senses. Out of uninterpreted
sense-experiences science cannot be distilled, no matter how industriously we
gather and sort them. Bold ideas, unjustified anticipations, and speculative
thought, are our only mans for interpreting nature: our only organon, our only
instrument, for grasping her.
The
old scientific ideal of episteme – of absolutely
certain, demonstrable knowledge- has proved to be an idol. The demand for
scientific objectivity makes it inevitable that every scientific statement must
remain tentative for ever. It may indeed be corroborated, but every
corroboration is relative to other statements which, again, are tentative. Only
in our subjective experiences of conviction, in our subjective faith, can we be
“absolutely
certain”. (Page 278 – 280)
Remarks
The
idea proposed in this book is still the fundamental idea in problem solving in
business fields. We always begin with a hypothesis when we tackle problems.
After coming up with the hypothesis, we test it by collecting facts and
checking the chain of reasoning. If we find the facts or logical fallacies
which reject the hypothesis, we turn down the original one and try to find out the
new.
What
this book is missing unfortunately is how the motivation and intuition that
change the structure of science come to us. People now are striving to find out
the more systematic way to get to the world-changing idea. Granted, that part
is not the scope of this book, but I just wanted to know how Popper thought of
the process of the idea generation.
Reference
Karl
Popper, “The Logic of
Scientific Discovery”, Routledge
(2nd edition), 2002/3/29
