According to Evidential Pluralism, mechanistic studies should be scrutinised alongside comparative studies when evaluating a causal claim. This leads to new approaches to evidence-based medicine and evidence-based policy making, for example. Talks in this series consider Evidential Pluralism and/or alternative approaches to handling diversity of evidence in causal enquiry.

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2025

29 September. 3-4.30pm Jonathan Fuller (Pittsburgh). An argument framework for evidence synthesis and evidence-to-decision analysis.

From its concepts for appraising evidence to its principles of evidence-based decision-making, evidence-based medicine (EBM) implicitly relies on a measurement theory of medical evidence. In the measurement theory, evidence is epidemiological measurements of clinical outcomes. In the first part of this talk, I argue that the evidential pluralist about health technology assessment must search for evidence beyond clinical epidemiology, but also beyond the narrow conception of evidence and narrowly applicable tools of the measurement theory. Instead, they should turn to an argument theory of medical evidence, an idea adapted from work done by Nancy Cartwright and Jeremy Hardie. In the argument theory, evidence is facts or data that supports premises in argumentation for medical hypotheses. The argument theory underwrites an argument framework for evidence synthesis and evidence-to-decision analysis. In the second part of the talk, I introduce the fundamentals of the argument framework. The framework uses tools such as nodal diagrams and principles from the sciences of reasoning – including logic, statistics, and epistemology – to organize practical reasoning towards decisions as well as epistemic reasoning about the effectiveness and safety of health technologies. Though broadly applicable, it is most promising for contexts in which diverse evidence is available that cannot be ‘amalgamated’ using homogenizing measurement instruments and instead must be ‘synthesized’ through complex argumentation.

21 October. 3-4.30pm Miriam Solomon (Temple University). How to be an Evidential Pluralist.

I have seen a number of different definitions of evidential pluralism (previously “EBM+”), ranging from the strict Russo-Williamson thesis (2007) to more relaxed views of the appropriate epistemic roles of hypotheses about mechanisms and evidence of mechanisms. In this talk I draw on cases in the recent history of science and medicine, especially the early years of the Covid pandemic, to argue that evidence for the appropriateness of epistemic humility about knowledge of mechanisms supports a more careful description of how to be an evidential pluralist.

3 November. 3-4.30pm. David Fisman (Toronto). The Idea of Modeling: Climbing the Ladder of Causality in Epidemiology.

Evidence-based medicine frameworks such as GRADE elevate randomized controlled trials (RCTs) as the highest form of causal evidence. But in Judea Pearl’s Ladder of Causality, it is models (simplified representations of reality, often mathematical or graphical in nature) that enable the deepest causal insight. In this talk, I explore two complementary modeling traditions. Infectious disease models are dynamic and recursive, capturing the feedback inherent in epidemics and enabling simulation of interventions over time. The non-independence of outcomes when diseases are communicable may mean that RCTs are infeasible; the nature of public health emergencies may mean that RCT are unethical. A second modeling framework relates to directed acyclic graphs (DAGs), which are static but powerful tools for clarifying assumptions, identifying confounding, and formalizing causal questions (and are indeed closely related to recent transformative developments in artificial intelligence). Together, these modeling approaches allow us to reason beyond mere association or experimental data. As the late Babak Pourbohloul said: “Models move us from data to understanding. Once we understand, we can predict and control.” Modeling is not a fallback when RCTs fail; it is often the most rigorous and honest way to truly understand how systems work.

1 December. 3-4.30pm. Kevin C. Elliott (Michigan). Alleviating Epistemic Injustice: Strategies from Science and Values.

The concept of epistemic injustice can be a powerful tool for characterizing the experiences of those who strive to address environmental health threats in their communities but who are illegitimately dismissed as being ignorant or misinformed. This talk explores how philosophers can potentially contribute to understanding and alleviating these epistemic injustices—especially hermeneutical injustices—by drawing from the literature on science and values. This literature highlights contingent scientific choices that experts and community members can reasonably handle in different ways. The talk will examine several of these contingent choices, including choices about background assumptions, research questions, and standards of evidence. Additionally, the talk will show how philosophers can carefully consider how particular forms of engaged scholarship with scientists and/or community members would enable them to draw on these insights from the science-and-values literature in the most effective and ethically responsible ways.

Past talks

2025

20 March, 4-5.30pm. Gary Goertz (Notre Dame) & Stephan Haggard (UCSD). Evidential Pluralism: The Example of Multi-method Large-N Qualitative analysis.

In other work, we have explored methodological issues around a research approach we call Large-N Qualitative Analysis (LNQA). The core of the method combines a consideration of regularities and within-case causal inference of all cases falling within a specified scope. In this talk, we outline a particular variant of this approach: multimethod LNQA or M-LNQA. The distinctive feature of M-LNQA is that it combines a statistical and LNQA component and thus raises interesting issues about evidential pluralism: how evidence of very different sorts can be combined to strengthen inference.

14 April, 3-4.30pm. Alexandra Trofimov (Manchester). How Evidential Pluralism mitigates epistemic injustice in evidence-based evaluation.

The aim of this paper is to demonstrate how Evidential Pluralism, an emerging account of the epistemology of causality, can help to avoid epistemic injustice in evidence-based evaluation. This, in turn, supports the adoption of Evidential Pluralism as a new methodology for evaluation. By prioritising certain kinds of evidence and devaluing or excluding other kinds of evidence, orthodox evidence-based approaches can lead to epistemic injustice. In contrast, by advocating a more inclusive approach to evidence, Evidential Pluralism is able to avoid the epistemic injustices committed by orthodox evidence-based approaches. These arguments are supported by consideration of three case studies concerning Covid-19 public face mask mandates, global value chains for development and consent to participate in non-pharmaceutical interventions.

12 May, 3-4.30pm. Christopher Clarke (Rotterdam). Against causal pluralism.

Causal pluralism claims that there are two types of causation: causal difference-making, which is defined in terms of counterfactual conditionals; and causal production which cannot be defined in terms of counterfactuals. Quantitative social science studies causal difference-making, while qualitative social science studies causal production. Or so it is claimed. I argue against causal pluralism from a conceptual engineering perspective. While the concept of causal difference-making has a clear role to play in our reasoning (namely guiding rational decision-making), the concept of causal production does not have a clear role to play. For example, I look at the suggestion that causal production might have a role to play in helping us decide who is morally and legally responsible for a given outcome. I argue against this suggestion, thereby casting doubt on causal pluralism. In light of this, qualitative social scientists would be better off adopting evidential pluralism rather than causal pluralism. (Throughout the talk I will also advertise some results from my draft monograph “Causation Reengineered”.)

16 June, 2-3.30pm Phyllis Illari (UCL). Epistemic games and causal problems: a framework for teaching the evaluation of scientific information.

Studies in science education demonstrate that laypeople typically engage with science to meet situation-specific needs. Their interest in science often emerges only when it directly helps them solve a particular problem. However, most research in science education has focused on evaluating the trustworthiness of information and the level of understanding required for its use. Less attention has been given to assessing the appropriateness of scientific information for specific purposes while recognizing its limitations. This paper aims to address this gap by proposing a framework to help laypeople evaluate scientific information in a purpose-specific manner. The framework introduced in this paper is based on the philosophical classification of causal information and its relevance to four scientific problems: inference, explanation, prediction, and control. It categorizes causal information into two types of epistemic games used by scientists: difference makers search and production or mechanism search. By understanding these games, laypeople can better assess the merits and limitations of scientific information relative to their specific needs. The paper also offers insights into how this framework can be taught in educational settings, with a focus on genetics education as an example. The aim is to enhance students’ capacity to critically engage with scientific information, thereby improving their ability to make informed decisions based on the specific needs and challenges.

30 June. 3-4.30pm Federica Russo (Utrecht). How is Who. Evidence as Clues for Action in Participatory Research Interventions.

Participatory and collaborative approaches in sustainability science and public health research contribute to co-producing evidence that can support interventions by involving diverse societal actors that range from individual citizens to entire communities. However, existing philosophical accounts of evidence are not adequate to deal with the kind of evidence generated and used in such approaches. In this paper, we present an account of evidence as clues for action through participatory and collaborative research inspired by philosopher Susan Haack’s theory of evidence. Differently from most accounts of evidence for use in policies and interventions, our account combines action-oriented (the how) and actors-oriented (the who) considerations. We build on Haack’s theory and on the analysis of examples of participatory and collaborative research in sustainability science and public health research to flesh out six procedural criteria for the generation and mobilization of evidence in and from participatory research. Action-oriented criteria invite to look at evidence from a (a) foundherentist, (b) gradational and (c) quasi-holistic perspective. Actors-oriented criteria point out that evidence generation and utilization are (d) social, (e) personal, and (f) embedded. We suggest that these criteria may reinforce participatory and collaborative approaches to evidence co-production when addressing complex problems in sustainability science and public health allowing for the generation of a kind of practical objectivity.

21 July. 3-4.30pm Rosa Runhardt (Radboud) & Jon Williamson (Manchester). Evidential Pluralism and educational ethnography.

Evidence-based policy is typically grounded in a narrow conception of evidence, one that prioritizes comparative studies and quantitative meta-analyses as the preferred base for establishing causal claims. However, this prevailing theory of evidence—often implicitly adopted in policy contexts—faces serious limitations when it comes to capturing the complexity of social interventions, particularly in fields such as education. We argue that this narrow conception ignores the extensive volume of knowledge that is generated in research fields such as educational meta-ethnography. Far from being epistemically inferior, we contend that meta-ethnographies could make an essential contribution to the evidential base for policy. By analysing meta-ethnography using the Evidential Pluralism framework (which scrutinises evidence of mechanisms alongside evidence of correlation), we show that meta-ethnographic studies can be fruitfully reinterpreted as providing evidence of a mechanism complex. This evidence can play a crucial critical role, as meta-ethnography shows how the complex enables, reinforces, or counteracts a policy of interest. We will illustrate this potential use of meta-ethnography using an example, Holly Craggs and Catherine Kelly’s qualitative meta-synthesis of adolescent experiences of school belonging (2018).

These seminars are organised by the team of the Interdisciplinary Systematic Review project in the Philosophy Department at the University of Manchester.