Chair of public health at Collège de France, Paris

1. Causal Pluralism and
Public Health
Federica Russo
Philosophy & ILLC | University of Amsterdam
russofederica.wordpress.com |@federicarusso
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2. Outline
 How to ask philosophical questions about causation
 And make philosophy relevant to science and policy
 Causal pluralism
 The selection of relevant philosophical questions and scientific problems of causality
 Public health challenges and evidential pluralism
 Why pluralistic approaches to causality and evidence can help address challenges in
public health
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3. Philosophizing about causation
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4. Causality is a key concept
 In every-day contexts
 Had I heard the alarmclock, I wouldn’t have missed the bus
 When I switch the button, the light turn on/off
 In scientific contexts
 Poverty causes delinquency
 SARS-CoV-2 causes respiratory difficulties
 In decision contexts
 Increasing tobaco taxation reduces smoking
 School closure for 2 weeks limits positive Covid cases
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5. But what is causation?
 A long-standing, ever-green question in philosophy
 From the Greeks, and possibly before
 Key conceptual shifts from the scientific revolution owards
 Ups and downs in contemporary thinking
 The typical philosophical questions:
 What is causation / causality?
 What are causes?
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6. Not one, but many questions
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7. Making sense of
a vast intellectual enterprise
 Philosophical theorising about causes
 Long history, ups and downs, harsh criticisms, dominant views, etc
 Expansion of philosophical theorising about causes
 Beyond physics, attention to the special sciences, medicine, and
epidemiology
 Attention to questions about use, besides traditional metaphysics,
epistemology, and semantics
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8. Causal pluralism
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Causality cannot be reduced to one single concept
but has to be analysed using several concepts

9. 5 philosophical questions
Metaphysics
What is causality? What kind of things are causes
and effects?
Semantics
What does it mean that A causes B?
Epistemology
What notions guide causal reasoning?
Methodology
How to establish whether A causes B? Or how much
of A causes B?
Use
What to do once we know that A causes B?
5 scientific problems
Inference
Does A cause B? To what extent?
Prediction
What to expect if A does (not) cause B?
Explanation
How does A cause or prevent B?
Control
What factors to hold fixed to study the relation
between A and B?
Reasoning
What considerations enter in establishing whether /
how / to what extent A causes B?
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10. Use
Metaphysics
Semantics Epistemology
Methodology
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11. The causal mosaic
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12. Tiles for the Causal
Mosaic
…
necessary and sufficient;
levels; evidence;
probabilistic causality; counterfactuals;
manipulation and invariance; processes;
mechanisms; information;
dispositions;
exogeneity; Simpson’s paradox;
regularity; variation;
action; inference;
validity; truth;
…
To be arranged by:
Philosophical Questions
Metaphysics, Semantics,
Epistemology,
Methodology, Use
Scientific Problems
Inference, Prediction,
Explanation, Control,
Reasoning
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13. A causal mosaic
A picture made of tiles
Each tile has a role that
Is determined by the scientific problem / philosophical question
it addresses
Stands in a relation with neighbouring concepts
A causal mosaic is dynamic, partly depends on scientists’
/ philosophers’ perspectives
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14. Public health challenges and
the benefits of a pluralistic approach
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15. Six causal challenges
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16. 1. [Causal Narrative] Choose the most effective way to explain disease and then
intervene (direct paths versus very indirect paths)
2. [Level of aggregation] Pitch the right or best level of intervention: individual versus
population, different types of social aggregation
3. [Types of factors] Choose the right or best factor(s) to intervene upon: bio-chemical
and/or socio-economic factors. Partly dependent on one’s metaphysical views about
disease causation
4. [Cause vs risk] Understand the conceptual borders between “risk” and “cause”, with
implications for the actionability of risks and causes, and to the communication to
general public
5. [Evidential pluralism] Assess the evidence and choose methods to form the
knowledge base and to design interventions. Assess how much evidence of
correlation and/or of mechanisms is needed to have a solid enough knowledge base
6. [Causes and norms] Concepts of health and disease are not “causally neutral.”
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17. 1. [Causal Narrative] Choose the most effective way to explain disease and then intervene
(direct paths versus very indirect paths)
2. [Level of aggregation] Pitch the right or best level of intervention: individual versus
population, different types of social aggregation
3. [Types of factors] Choose the right or best factor(s) to intervene upon: bio-chemical and/or
socio-economic factors. Partly dependent on one’s metaphysical views about disease
causation
4. [Cause vs risk] Understand the conceptual borders between “risk” and “cause”, with
implications for the actionability of risks and causes, and to the communication to general
public
5. [Evidential pluralism] Assess the evidence and choose methods to form
the knowledge base and to design interventions. Assess how much
evidence of correlation and/or of mechanisms is needed to have a solid
enough knowledge base
6. [Causes and norms] Concepts of health and disease are not “causally neutral.”
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18. Evidential pluralism
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19. From causation to
evidence for causal relations
 Evidential pluralism: one typically needs both evidence of correlation and evidence
of mechanisms to establish a causal claim.
 Epistemology and methodology
 How to establish whether A causes B
 Not a fool-proof approach: some correlation and some mechanism are needed to have
some explanation of the phenomenon at stake
 Not metaphysics
 Causation is not reduced to correlation or to mechanisms, or to the sum of the two
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20. Contrast and compare
Evidence-based medicine
 Uses evidence hierarchies or ‘GRADE’
systems
 Evidence of correlation is typically
considered superior
 RCTs and meta-analyses are gold
standard
 Evidence of mechanisms is typically
downplaid
Evidential pluralism
 Rejects stricts hierarchies
 Advocates for a plurality of methods
for evidence generation and evidence
assessment
 Quantitative, experimental,
observational, and even case reports
 Explains how to evaluate evidence of
mechanisms
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21. Evidential pluralism and public health
 [E of Correlation] Knowing that smoking causes lung cancer
 [E of Mechanism] Knowing how smoking causes lung cancer
 Knowing aspects of [that] and of [how] can help set up PH interventions at different
levels (see also challenges 2,3), e.g.:
 [That] > blanket policy banning smoking in public places; raising tobacco taxation, …
 [How] > targeted policies in schools, pregnant women, specific workplaces, …
 N.B.: mechanisms are bio-psycho-social, not just bio-chemical
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22. How much of ‘that’ and ‘how’
is needed?
 [That] and [How] license different inferences and interventions
 In ideal situations, and in real-world scenarios
 Often, we need to intervene on the basis of some [That] and very little [How]
available
 See e.g. Covid lockdown strategies in 2020
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23. Back to causal pluralism
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24. Causal pluralism and
the design of interventions
1. How much do we really need to know about the target population to properly
intervene? (Explanation, control)
2. How likely it is that implementing X we’ll get the sought result Y? (Inference,
prediction)
 Being clear about 1. and 2. helps with
 Generation and assessment of evidence (evidential pluralism)
 Design of PH interventions
 Communication between experts and with the general public
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25. Spelling out the complexity,
rather than reducing it
 PH faces complex, wicked problems
 We tend to think that to make problems tractable, we need to reduce complexity
 With causal and evidential pluralism we can spell out the complexity
 Which causal question is of relevance?
 How much of [That] / [How] is needed? For what purpose?
 Which aspects of [That] / [How] will be communicable to the public?
 Which values are we promoting with intervention X or Y?
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26. To sum up and conclude
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27. Philosophy at the service of public health
 Evergreen philosophical questions about causation can be made relevant to the
practice of science and in policy contexts
 Causal pluralism and evidential pluralism are ways to
 Promote looking at practices of science and policy design more closely
 Design conceptual approaches to causality and evidence that
 Help in the practice of evidence generation and assessment and policy design
 Improve communication between experts and with the general public
When problems are complex,
complexity has to be spelled out, not reduced
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28. Causal Pluralism and
Public Health
Federica Russo
Philosophy & ILLC | University of Amsterdam
russofederica.wordpress.com |@federicarusso
28
Thanks for your attention

29. Types of causing
Anscombian pluralism: pulling, pushing, binding, …
Aristotelian causes
Concepts of causation
Hall: Dependence vs production
Types of inferences
Inferential bases, inferential targets.
Epistemic causality
Sources of evidence
Difference-making and mechanisms
Methods for causal inference
Quantitative, qualitative, observational, experimental, …
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