PHILOSOPHY OF SCIENTIFIC EVIDENCE VS SCIENTIFIC RADIFICALISM
: Re-examining Randomized Clinical Trials (RCTs)
-Dr. Rajan R Patil.
There is increasing uneasiness on over-reliance on certain method scientic enquiry/methods (eg.
Radomised clinical trials) as the only and ultimate evidence of truth. Today unfortunately,
Radomized Control Trials (RCTs) is considered to be gold standard not because it is actually
best- but because is better among current available instruments for establishing evidence in
Medical science. Now, how do we define best ? which inherently is a relative term, it suggest of
lack of credible alternative.
The circular reasoning applied - evidence generated by RCT is the Best (in today’s time),
currently since this best comes out of RCT, hence RCT becomes the best tool.
I wonder, in the course of scientific evolution- What will happen if some day RCT as a theory
and concept is faulted and is replaced by alternative theory, a very distinct possibility, given the
propencity of science to grow and evolve, making RCT redundant-what will happen to all the
‘scientific evidence’ that we have accumulated in last 70 years that has dictated the medical
practice and policy decision in public health. So we need to be open about
Think of malaria, we have perfect science(we think so) accumulated over a century time
evidence -but still we continue to be helpless . Well some may argue, its not because of science
but because of sociology and programm management issues. How does one explain stupendous
success Small pox - not withstanding the very same sociology and programme management
challenge in disease control initiative (infact more in that era, given the literacty rates and lesser
prosperity). That makes me wonder if we are making sociology and management of disease
control as alibi to cover up short comings for the deficiencies of our current ‘evidence based
tools’ with which we are fighting malaria/TB?
I had been actually thinking about these issue in those lines in the recent past more in public
health context-, but thanks to your concerns and ethical issues raised - prodded me to look at the
- philosophy of generating evidence in science from historical/philosphical perspective- On how
the concept of ‘scientific evidence’ and methods of generating it has evolved over time.
I present below some logical and philosophical arguments by some of the greatest science
thinkers who have questioned science in their times.
EVOLUTION OF PHILOSOPHY OF SCIENTIFIC INFERENCE-Across time.
Francis Bacon's Novum Organum, which, in 1620, presented an inductivist view of science. In this philosophy,
scientific reasoning is said to depend on making generalizations, or inductions, from observations to general laws
of nature; the observations are said to induce the formulation of a natural law in the mind
Russell was not alone in his lament of the illogicality of scientific reasoning as ordinarily practiced. Many
philosophers and scientists from Hume's time forward attempted to set out a firm logical' basis for scientific
reasoning. a number of philosophers noted that scientific statements can only be found to be consistent with
observation, but cannot be proven or disproven in any "airtight" logical or mathematical sense (Duhem, 1906,
transl. 1954; Popper 1934, transl. 1959; Quine, 1951).
This fact is sometimes called the problem of nonidentiftcation or underdetermination of theories by observations
(Curd and Cover, 1998). In particular, available observations are always consistent with several hypotheses that
themselves are mutually inconsistent, which explains why' (as Hume noted) scientific theories cannot be logically
proven. In particular, consistency between a hypothesis and observations is no proof of the hypothesis, because we
can always invent alternative hypotheses that are just as consistent with the observations.
In contrast, a valid observation that is inconsistent with a hypothesis implies that the hypothesis as stated is false
and so refutes the hypothesis. If you wring the rooster's neck before it crows and the sun still rises, you have
disproved that the rooster's crowing is a necessary cause of sunrise. Or consider a hypothetical research program to
learn the boiling point of water (Magee, 1985). A scientist who boils water in anopen flask and repeatedly measures
the boiling point at lOO°C will never, no matter how many confirmatory repetitions are involved, prove that 100°C
is always the
boiling point. On the other hand, merely one attempt to boil the water in a closed flask or at high altitude will refute
the proposition that water always boils at 100°C.
refutationism or falsificationism. Refutationists consider induction to be a psychologic crutch: Repeated
observations did not in fact induce the formulation of a natural law, but only the belief that such a law has been
found, For a refutationist, only the psychologic comfort provided by induction explains why it still has advocates.
The philosophy of conjecture and refutation has profound implications for the methodology of science. The
popular concept of a scientist doggedly assembling evidence to support a favorite thesis is objectionable from the
standpoint of refutationist philosophy because it encourages scientists to consider their own' pet theories as their
intellectual property, to be confirmed, proven, and, when all the evidence is in, cast in stone and defended as
natural law. Such attitudes hinder critical evalua-
tion, interchange, and progress. The approach of conjecture and refutation, in contrast, encourages scientists to
consider multiple hypotheses and to seek crucial tests that decide between competing hypotheses by falsifying one
of them. Because falsification of one or more theories is the goal, there is incentive to depersonalize the theories.
Criticism leveled at a theory need not be seen as criticism of the person who proposed it. It ha been suggested that
the reason why certain fields of science advance rapidly while others languish is that the rapidly advancing fields
are propelled by scientists
who are busy constructing and testing competing hypotheses; the other fields, in contrast, "are sick hy comparison,
because they have forgotten the necessity for alternative hypotheses and
CONSENSUS AND NATURALISM
Some 20th-century philosophers of science, most notably Thomas Kuhn (1962), emphasized the role of the
scientific community in judging the validity of scientific theories. These critics of the conjecture-and-refutation
model suggested that the refutation of a theory involves making a choice. Every observation is itself dependent on
theories. For example, observing the moons of Jupiter through a telescope seems to us like a direct observation, but
only because the theory of optics on which the telescope is based is so well accepted. When confronted with a
refuting observation, a . cientist faces the choice of rejecting either the validity of the theory being tested or the
validity of the
refuting observation, which itself must be premised on scientific theories that are not certain (Haack, 2003).
Observations that are falsifying instances of theories may at times be treated as "anomalies," tolerated without
falsifying the theory in the hope that the anomalies may everitually be explained .
In other instances, anomalies may lead eventually to the overthrow of current scientific doctrine, just as
Newtonian mechanics was displaced (remaining only as a first-order approximation) by relativity theory. Kuhn
asserted that in every branch of science the prevailing scientific viewpoint, which he termed "normal science,"
occasionally undergoes major shifts that amount to scientific revolutions. These revolutions signal a decision of the
scientific community to discard the scientific infrastructure rather than to falsify a new hypothesis that cannot be
easily grafted onto it. Kuhn and others have argued that the consensus of the scientific community determines what
is considered accepted and what is considered refuted.
Kuhn's critics characterized this description of science as one of an irrational process, "a matter for mob
psychology" (Lakatos, 1970). Those who believe in a rational structure for science consider Kuhn's vision to be a
regrettably real description of much of what passes for scientific activity, but not prescriptive for any good
science. Although many modem philosophers reject rigid demarcations and formulations for science such as
refutationism, they nonetheless maintain that science is founded on reason, albeit possibly informal common
sense (Haack, 2(03). Others go beyond Kuhn and maintain that attempts to impose a singular rational structure or
methodology on science hobbles the imagination and is a prescription for the same sort of authoritarian
repression of ideas thatsientists have had to face throughout history (Feyerabend, 1975 and 1993).
The philosophic debate about Kuhn's description of science hinges on whether Kuhn meant to d cribe only what
has happened historically in science or instead what ought to happen, an issue bout which Kuhn (1970) has not been
completely clear:The idea that science is a sociologic process, whether considered descriptive or normative, is
interesting thesis, as is the idea that from observing how scientists work we can learn about how scientists ought to
work. The latter idea has led to the development of naturalistic philosophy science, or "science studies," which
examines scientific developments for clues about methods scientists need and develop for successful discovery and
invention (Callebaut, 195 Giere, 1999).
IMPOSSIBILITY OF SCIENTIFIC PROOF
Vigorous debate is a characteristic of modern scientific philosophy, no less in epidemiology than il other areas
(Rothman, 1988). Can divergent philosophies of science be reconciled? Haack (2003 suggested that the scientific
enterprise is akin to solving a vast, collective crossword puzzle. In area in which the evidence is tightly interlocking,
there is more reason to place confidence in the-answers but in areas with scant information, the theories may be little
better than informed guesses. Of th scientific method, Haack (2003) said that "there is less to the 'scientific method'
than meets the eye
Is scientific inquiry categorically different from other kinds? No. Scientific inquiry is continuou with everyday
empirical inquiry=-only more so."Perhaps the most important common thread that emerges from the debated
philosophies is tha proof is impossible in empirical science. This simple fact is especially important to observationa
epidemiologists, who often face the criticism that proof is impossible in epidemiology, with tln implication that it is
possible in other scientific disciplines. Such criticism may stem from a viev
that experiments are the definitive source of scientific knowledge. That view is mistaken on at leas two counts. First,
the nonexperimental nature of a science does not preclude impressive scientific discoveries; the myriad examples
include plate tectonics, the evolution of species, planets orbiting other stars, and the effects of cigarette smoking on
human health. Even when they are possible experiments (including randomized trials) do not provide anything
approaching proof and in fact may be controversial, contradictory, or nonreproducible. If randomized clinical trials
provide proof, we would never need to do more than one of them on a given hypothesis. Neither physica nor
experimental science is immune to such problems, as demonstrated by episodes such as experimental "discovery"
(later refuted) of cold fusion (Taubes, 1993).Some experimental scientists hold that epidemiologic relations are only
suggestive and believt that detailed laboratory study of mechanisms within single individuals can reveal cause-
effect relations with certainty. This view overlooks the fact that all relations are suggestive in exactly the manner
discussed by Hume. Even the most careful and detailed mechanistic dissection of individual events cannot provide
more than associations, albeit at a finer level. Laboratory studies often involve a degree of observer control that
cannot be approached in epidemiology; it is only this control, not the level of observation, that can strengthen the
inferences from laboratory studies. And again, control is no guarantee against error. In addition, neither scientists
nor decision makers are ofter highly persuaded' when only mechanistic evidence from the laboratory is available.All
of the fruits of scientific work, in epidemiology or other disciplines, are at best only tentativi formulations of a
description of nature, even when the work itself is carried out without mistakes The tentativeness of our knowledge
does not prevent practical applications, but it should keep us skeptical and critical, not only of everyone else's work,
but of our own as well. Sometimes etiological
hypotheses enjoy an extremely high, universally or almost universally shared, degree of certainty The hypothesis
that cigarette smoking causes lung cancer is one of the best-known examples. Thes hypotheses rise above
"tentative" acceptance and are the closest we can come to "proof." But ever these hypotheses are not "proved" with
the degree of absolute certainty that accompanies the proof of a mathematical theorem.
Ref : Kenneth J Rothman et al. Modern Epidemiology. 3rd Ed.
Reviewing this literature was personally an extemely enriching experience, helped me to widen
my horizon giving very different perspective. I thought will circulate this to other colleagues as
well to guard ourselves from indulging oursevles in scientific radicalism, becuase the evidence or
theory that we swear by today may be redundant tomorrow.
Morale of the story:
Sitaraon ke aage jahaan aur bhi hai !!
Dr. Rajan R Patil
PhD scholar in Respiratory Health.
Division of Epidemiology
School of Public Health
Potheri, Kattankulathur - 603203
Cell: 9445811610 & 9025378036
Email : email@example.com