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Outline
Medical epistemology:
Forms of rationality in medicine and health care
Bjørn Hofmann
University of Oslo
University College of Gjøvik
Norway
• Rationality, definition
• Scientific forms of rationality (brief outline)
– Inference
– Theory testing
– Causation
– Hypothesis testing
– Reductionism versus holism
• Other forms of rationality
Rational
• From late latin (1560‐79), ratiōnālitās, meaning reasonableness.
Rationalism
• Rationalism is "any view appealing to reason as a source of knowledge or justification" (Lacey, A.R. (1996), A Dictionary of Philosophy, 1st edition, Routledge and Kegan Paul, 1976. 2nd edition, 1986. 3rd edition, Routledge, London, UK, 1996: 286)
• Rationalism is a method or a theory "in which the criterion of truth is not sensory but intellectual and deductive" (Bourke, Bourke, Vernon J. "Rationalism", in Runes, Dagobert D. (ed., 1962), Dictionary of Philosophy, Littlefield, Adams, and Company, Totowa, NJ 1962: 263)
Many sciences and many rationalities
Rationalism going astray
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•
•
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SIDS
Endoscopy
Removing colon to treat epilepsy
Proton therapy
– Hofmann B. Fallacies in the arguments for new technology: the case of proton therapy. Journal of Medical Ethics 2009; 35: 684‐687.
Economy
Biology
Genetics
Esthetics
Law
Epidemiology
Anatomy
Ethics
SPECIALITIES
Psychology
“Medicine”
Sociology
Physiology
Anthropology
Organization theory
Molecular biology
Biochemsitry
Pathology
Technology
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Theories and models
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•
•
•
•
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Supernatural Theories
Hippocratic Theory
Miasma
Theory of Contagion
Germ Theory (cause shown via Henle‐Koch postulates)
Classic Epidemiologic Theory
PART 1
Science affiliated Rationality
– cause given by e.g. Hill’s viewpoints of causation or counterfactual conceptions of causation
• Multicausality and Webs of Causation Modes of inference
Deduction
Induction
Abduction
• Deduction
from general
to particular
• Inference from
particular
observations to
general
statements
• Probable
inference
• Inference to best
explanation
• Probable
inference
• We have
observations, and
find the
hypothesis that
best explains the
observations
• Necessary
inference
Testing scientific hypotheses
• Hypothetical deductive method
– Verification
– Falsification
• Critical rationalism (Popper)
Hypothetic deductive method
1. Formulate a hypothesis – My lorry is lower than this beam.
2. Deduce the empirical consequences
– I can drive under the beam without crashing
3. Experiment: – I drive
4. Accept or reject hypothesis dependant on the results in 3.
– My lorry is not lower than this beam
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Hypothesis about DNA?
System
‐biological
‐social
Model
‐teoretical
Hypothesis
Eksperiments
Observations
Deduction
Empirical Consequences
‐ prediction
Data
Verification versus Falsification
Falsification
• Choose alternative hypothesis, and by • Choose hypothesis with falsify them, strengthen own respect to what we believe hypothesis
to be true
• Support theories
• ”Confirm theories”
• Increase knowledge by restriction
• Increase knowledge accumulative
Verification
Knowledge: falsify
hypotheses
Correspondence?
Knowledge
NO
YES
Accept the
hypothesis
Causation
Causation
• Determinism
–
–
–
–
Not falsifies
hypotheses
Reject the
hypothesis
Necessary and sufficient conditions
Necessary conditions
Sufficient conditions
INUS conditions
• Probabilistic theories of causation
– Bradford Hills viewpoints on causation
Generalists
Singularists
Causation depends on general patterns
Causation can be seen in single instances
Externalists
Internalists
Extrinsic features determine whether a sequence
is causal. Causation is external to the
object(s)
Intrinsic features determine whether a sequence
is causal. Causation is something internal
in the object(s). Independent of outer
factors.
Reductionists
Supervenience
Non-reductionists
Truth conditions for causal
statements is fully specified
by non-causal features.
Causation is ontically nonautonomous: ontically
dependent on non-causal
features.
Weak ontic dependence:
Non-causal facts fix the
causal facts.
Causal facts supervene on
non-causal facts.
Causation can be seen in single
instances.
Causation is ontically
autonomous
• Testing for causation / models of causation
– Counterfactual conception of causation
– Causal pies (Rothman)
– Web of causation
↓
Non-Humeans
Humeans
Humean supervenience (HS): causal facts
supervene on non-causal facts. I.e. there is
no robust necessity in causation, and in
nature in general!
Causation is an autonomous feature of the world.
Causal events do not supervene on noncausal facts.
Causation is tied to regularity: invariability
Causation is an intrinsic relation among singular
events.
Psillos 2002
Reductionism versus holism
Reductionism
Holism
Man can be understood by
the sum of its parts
Man is more than
the sum of its parts
COMPLEX
CONCEPTION:
Man is an interplay
between physiological,
emotional, social and
cultural condition.
Holism
Holism, from Greek ”holos”, whole, is ”the view that an organic or integrated whole has a reality independent of and greater than the sum of its parts” (Websters dictionary)
Two kinds of holism:
• Epistemic holism
• Ontological holism
(Nortvedt & Grimen 2004)
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Epistemic Holism
• What we know and believe consists of a loosely connected whole. – There is not an one‐to‐one relationship between particular propositions about the world and particular facts. What is important is how our whole system of knowledge relates to the world (ref. H.O. Quine)
– Changes in parts of our system of knowledge will have effects on the whole system. (We strive for coherence)
– All parts of our knowledge can be revised (although not at the same time). It is like rebuilding a ship on the sea
– We cannot see theories as isolated entities. Knowledge relates and constitutes a whole.
• See: Poincaré, Duhem, Neurath, Quine, Føllesdal
Reductionism
Reductionism is the conception that a phenomenon can be understood by studying its parts.
Trying to make things simpler.
X can be reduced to Y in a way that X can be eliminated (X is superfluous)
– Mechanical conception of man
– ”The error in the machine”
– Analytic‐synthetic thinking
Metaphysical
• The structure of the world represents a whole
– The wholes of the world are not available for analytical‐
syntactic thinking:
• We cannot decompose the phenomenon, study the parts, and by the analysis of the parts better understand the whole (by synthetis of the knowledge of the parts).
– In the same way we cannot understand water (with respect to freezing and boiling) by investigating oxygen and hydrogen, we cannot understand a human being by studying its organs, functions and processes. (”emergent property”)
Different kinds of reductionism
• Concept reductionism: We can reduce simple concepts to other concepts. – Behaviourism: mental conditions can be reduced to behaviour
– Mentalistic conceptions can be reduced to neurophysiological concepts (Churchland 1988)
• Law reductionism: One class of regularities/laws can be reduced to another class of regularities.
– Biological laws can be reduced to chemical laws, which can be reduced to physical laws.
– Empiricism
• Reduction of phenomenon (materialism): all phenomena can be conceived of (reduced) as being of a certain kind (e.g. Material) Reductionisms
As a research
program
Ontological Holism
Partial
reductionism
Total
reductionism
Biochemistry
Socio-biology
Unity of
science,
(physics)
Marxism,
Quantum
physics (new age)
Forms of rationality in handling uncertainty
Norms of rationality
• Logic
• Probability theory
• Confirmation theory
Heuristics:
• Salience
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–
–
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Concreteness
Proximity
Emotional interest
Perceptual biases
• Representativeness
– Causaual reasoning (assuming that similar events have similar causes)
• Availability
– biases in exposure and attention to data, – biases in memory retrieval, and salience
(Kahneman, Slovic and Tversky 1982; Nisbett and Ross 1980)
http://www.jstor.org/pss/188158
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Forms of rationality: Historicism
• Absolute rationality: given by nature or God
• Paradigms: Consensus (Kuhn, 1962)
• Research programs: new predictions (Lakatos
1970)
• Research traditions: problems solved (Laudan
1977)
– “it was rational to accept Newtonian mechanics and to reject Aristotelian mechanics by, say, 1800”, and “it was irrational after 1830 to accept the biblical chronology as a literal account of earth history” (Laudan, 1977)
Most research findings are false
Most research findings are not true because:
1. Bias
2. Repeated independent testing by different groups
–
With low power, low effect size, large number of tested relationships, financial interests
“Most Research Findings Are False for Most Research Designs and for Most Fields”
• ”PPV exceeding 50% is quite difficult to get.”
Ioannidis JPA (2005) Why most published research findings are false. PLoS Med 2(8): e124.
Annals of Science
The Truth Wears Off
Is there something wrong with the scientific method?
by Jonah Lehrer December 13, 2010 http://www.newyorker.com/reporting/2010/12/13/101213fa_fact_lehrer#ixzz1JPDulGuP
• The decline effect
• second-generation antipsychotics
• ”verbal overshaddowing” (Jonathan Schooler)
• weak coupling ratio exhibited by decaying neutrons
• Symmetry (in appearance) and reproductive selection (Anders Møller)
• Explanations:
• Publication bias (Ioannidis)
• “significance chasing,” i.e., finding ways to interpret the data so that it
passes the statistical test of significance
• Selective reporting: “selective reporting is not the same as scientific fraud”
but “one of subtle omissions and unconscious misperceptions”
•“a lot of extraordinary scientific data are nothing but noise.”
Most research findings are false
The research findings are less likely to be true if:
1. The studies conducted in a scientific field are small.
2. The effect sizes in a scientific field are small.
3. The number of tested relationships is great and the selection of tested relationships is small.
4. The flexibility in designs, definitions, outcomes, and analytical modes in a scientific field is great.
5. The financial and other interests and prejudices in a scientific field are great.
6. The hotter a scientific field (with more scientific teams involved).
Ioannidis JPA (2005) Why most published research findings are false. PLoS Med 2(8): e124.
We do not give up!
The significance of ”significance”
• “It feels good to validate a hypothesis,” …. “It feels even better when you’ve got a financial interest in the idea or your career depends upon it. And that’s why, even after a claim has been systematically disproven you still see some stubborn researchers citing the first few studies that show a strong effect. They really want to believe that it’s true.” John Ioannidis.
• “A “significant” result is defined as any data point that would be produced by chance less than five per cent of the time. This ubiquitous test was invented in 1922 by the English mathematician Ronald Fisher, who picked five per cent as the boundary line, somewhat arbitrarily, because it made pencil and slide‐
rule calculations easier.”
http://www.newyorker.com/reporting/2010/12/13/101213fa_fact_lehrer#ixzz1JPDulGuP
http://www.newyorker.com/reporting/2010/12/13/101213fa_fact_lehrer#ixzz1JPDulGuP
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Hierarchy of knowledge
Theoretical:
• General propositions about the world
• Abstract models
• Can be articulated (by language)
Hierarchy of sciences
• Natural sciences
• Social sciences
• Humanities
Practical:
• Related to experience (empirical).
• Related to particular cases.
• Can be articulated? (lingual, by action)
Norms of Science*
Hierarchy of evidence
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Meta‐analysis
Systematic reviews
Randomized Controlled Trial
Non‐randomized Trial
Observational studies
– Kohort study
– Case‐control study
– Case series
Economic rationality
PART 2
• Maximising utility
• Profit
• Market mechanisms
– The invisible hand
Science lookalike forms of rationality
• Tends to exclude:
– Justice
• Distributive justice
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Economic rationality
Judicial rationality
• Subsumption logic
• Analogical thinking
(casuistry)
Measuring utility and preferences:
1.Standard gamble
2.Time‐trade‐off
3.Rating scale/visual analog scale
Tends to ignore our preference dynamics
Judicial rationality
Taxonomic rationality
Classificatory values:
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• Whiplash
– Medical diagnosis?
– Judicial diagnosis?
Simplicity
Exclusiveness
Exhaustiveness
Practical utility
Status of diseases
Status of disease
Disease characteristics
• Organ placement (high‐low)
• Acute ‐ chronic
• Mortality
• Objective diagnostic signs, markers
• Presumed causality
Treatment characteristics
• Use of technology
• Dramatic
• Intervention
• Treatment response
Patient characteristics
• Age
• Sex
• Physician‐patient communication (mismatch)
• Disfigurement
• Helplessness
Album 1996; Album & Westin 2007
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Can du Ö Will do
Possibility Ö Disease
• Hi‐tech
• Hi‐touch
• Assistive reproductive technology => involuntary childlessness, infertility treatment
• Surgery reduces diabetes 2 => Diabetes becomes a surgical (and not a metabolic) disease (Lautz. Diabetes Care, 2011)
• Access to radiological services results in use
• Lysdahl KB, Hofmann B. What causes increasing and unnecessary use of radiological investigations? a survey of radiologists' perceptions. BMC Health Services Research 2009; 9: 155. • Lysdahl KB, Hofmann B, Espeland A. Radiologists' responses to inadequate referrals.European Radiology E‐pub ahead of print, November 17 2009. Imperative of possibility
• Can do – will do.
• If you do not do everything possible, you will
be held responsible.
• «We have to do (try) everything possible»
Rationality of extension
• “Too much of a good thing is wonderful.” Mae West
Imperative of action
• Better to act than not to act.
• «Do not just stand there, do something.»
• If you do not act, you will be held responsible.
• Professional identity is constituted by action, and not by non‐action.
Too much of a good thing is wonderful
• More than % 80 of all X‐ray examinations are negative.
• More than % 90 of all laboratory tests are negative.
• 10‐40 (80)% of all X‐ray examinations are unnecessary.
• 66 % of all laboratory tests are unccecessary. http://pmj.bmj.com/cgi/reprint/82/974/823
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More is better than less?
• 30% of radiological examinations are not compliant with guidelines
Images are
better than
numbers (and what we can
hear)
Carton M, Auvert B, Guerini H, Boulard JC, Heautot JF, Landre MF, Beauchet A, Sznajderi M, Brun‐Ney D, Chagnon S: Assessment of radiological referral practice and effect of computer‐based guidelines on radiological requests in two emergency departments. Clin Radiol 2002, 57: 123‐128.
• 20‐50% of the examinations are not justified
Malone JF: Radiation protection in medicine: Ethical framework revisited. Rad Prot Dosim 2009, 135: 71‐78.
• In Sweeden 20% of all CT‐examintations were not justified
Almén A, Leitz W, Richter S. National Survey on Justification of CT‐examination in Sweden. Rapport number 2009:03. Swedish Radiation Safety Authority.
Rationality of costs
• ”costlier is better” (Rank NEJM 2008;359:1424‐5)
Summary Forms of rationality
«Within science»
• Logic
• Internal norms of science
• Reductionism
• Holism
• Rationality of classification (taxonomy)
• Forms of inference
• Causation
– Cause ↠ effect
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Materialism versus vitalism
Physicalism
Mechanical rationality
Realism versus idealism
Rationalism versus empiricism
Hypothesis testing
– Verificationism
– Falsificationism
«Outside science»
• Economic rationality
• Legal rationality
• Bureaucratic rationality
• Business rationality
• Industrial rationality
• Action oriented rationality
– Imperative of action
• News oriented rationality
– The new > the old
• Rationality of extension
– Much is better than little
• Rationality of complexity
– Advanced is better than simple
• Knowledge bias: – To know > not to know
• Medicalization
Conclusion
• There is not one rationality in medicine and health care
• They have different sources and they interplay (beyond what is warranted by their premises)
• This gives a diverse epistemology
• Health care epistemology must analyse this diversity
• Many things seem reasonable (and hence rational)
• It is important (morally) to disclose forms of rationalities that are unwarranted and unjustified (judged by their own premises) in fields where people’s health is at stake
– This is a task for philosophy of medicine and health care
• We should be more explicit in analysing and disclosing our epistemological perspectives and presuppositions
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