Difference-Making and Explanatory Relevance

An international conference


The central question for any theory of explanation can be put in terms of relevance. What makes bits of information relevant to explaining why something is the case? Classical accounts of explanation (in terms of nomic expectability, causation, or certain statistical patterns) have frequently been criticized for not properly answering this question. In recent approaches to the question, philosophers have turned to the idea of making a difference. Causes, for instance, that make a difference to the occurrence of an event are relevant to explaining why that event occurred. This idea is present both in counterfactual accounts of explanation that have been advanced by Woodward and others as well as alternative approaches such as the one by Strevens. But the notion of difference-making has also been studied independently of the philosophy of explanation, for instance in the questions centring around free will and responsibility. 

The aim of the present conference is to bring together philosophers from different disciplines to present their newest research on the topics of difference-making and explanatory relevance.


Monday 12 July

3 pm Joaquim Giannotti (Birmingham): Grounding Laws as Difference-Makers

5 pm Jonathan Schaffer (Rutgers): Putting the Making Back into Difference-Making

Tuesday 13 July

3 pm Mario Günther (Canberra): Difference-Making Causation

5 pm Carolina Sartorio (Arizona): Difference-Making and Free Will Causalism

Wednesday 14 July

3 pm Josh Hunt (U Michigan): Norms to Explain By

5 pm Vera Hoffmann-Kolss (Bern): Interventionism, Monotonicity and the Problem of Variable Choice

Thursday 15 July

3 pm Hans Rott (Regensburg) & Eric Raidl (Tübingen):   Difference-making, Relevance, Contraposition: Towards a Logic of Because

5 pm Laura Franklin-Hall (NYU): High-Level Explanation and the Overshooting Problem

Friday 16 July

3 pm Nick Emmerson (Birmingham): Plumbing Metaphysical Explanatory Depth

5 pm Michael Strevens (NYU): Difference-Making and Mechanism


Nick Emmerson: Plumbing Metaphysical Explanatory Depth

The central aim of this talk is to motivate an account of depth in metaphysical explanation. With increasing interest in interventionist analyses of metaphysical explanation (Schaffer 2016, 2017; Wilson 2016, 2018; Reutlinger 2017), an accompanying account of metaphysical explanatory depth (MED) is conspicuous in its absence. In extending the analogy between grounding and causation, I shall argue that MED is similarly connected to the range of testing interventions under which an explanatory generalization remains invariant (Hitchcock & Woodward 2003b; Woodward 2003). After elucidating the notion, through two toy-examples, I demonstrate the important work which MED can perform in characterizing debate within metaphysics. Focusing, upon a novel approach to explaining the identity and distinctness of objects, I argue that Erica Shumener’s (2020) account is progressive with respect to prior proposals, precisely because it provides greater MED. Having established the utility of MED, I then turn this analysis to the metaphysics of explanation itself, with intriguing results.

Joaquim Giannotti: Grounding Laws as Difference-Makers

Some metaphysicians argue that we have compelling reasons for accepting grounding laws—general principles about what grounds what—in our theorizing. One is that they permit us to enjoy unified and systematic metaphysical explanations. Another is that grounding laws connect what is grounded with what does the grounding. My aim is to bolster the theoretical serviceability of grounding laws by showing that they are difference-makers. To accomplish this goal, I set out to do two things. First, I identify a suitable notion of difference-making partial ground that can be applied to the grounding laws. Second, I argue that the grounding interventionist framework has built-in resources for establishing that grounding laws are difference-making partial grounds. This merit does not just enrich the package deal of benefits advertised by grounding interventionism, but it also gives the sympathizers of grounding laws a reason in favour of this approach. My conclusion is that grounding interventionism is a promising approach for capturing the explanatory relevance of grounding laws.

Laura Franklin-Hall: High-Level Explanation and the Overshooting Problem

What distinguishes good scientific explanations, those that enlighten and captivate us, from their work-a-day peers, which may minimally account for the phenomena at hand but without inspiration? Abstraction is a popular answer. One explanation is more abstract than another when its explanans says less than does the other, ruling out fewer ways that the world might be. Yet accounts of explanation that aim to capture our preference for explanatory abstraction face the challenge of not embracing overly abstract explanations which say too little about an event’s run-up to be very explanatory of it. In prior work, I pressed this ‘overshooting’ challenge against the influential interventionist difference-making account of explanation, arguing that, at least with the resources already on offer, that account was unable to home in on explanations at the intuitively correct level. In this talk I will address two recent attempts to fill this gap. In each case, I will argue that these replies either don’t succeed, or do so only by making the kinds of metaphysical commitments that interventionists have aimed to avoid.

Mario Günther: Difference Making Causation

We put forth an analysis of causation. The analysis centers on the notion of a causal model that provides only partial information as to which events occur, but complete information about the dependences between the events. The basic idea is this: an event causes another just in case there is a causal model that is uninformative on both events and in which the first event makes a difference as to the occurrence of the other. We show that our analysis captures more causal scenarios than the other counterfactual accounts to date. 

Vera Hoffmann-Kolss: Interventionism, Monotonicity and the Problem of Variable Choice

One of the key challenges for interventionist theories of causation is to develop criteria for variable choice. Which variables should be included in a causal model describing a system or a situation? In this paper, I argue that the set of variables constituting a model should satisfy the following monotonicity requirement: the causal relations occurring in the model should not disappear if further variables are added to it. Moreover, I argue that these further variables, which are hypothetically added to test the adequacy of a model, must satisfy several constraints. In particular, they must be at least as natural as the variables already contained in the model. I conclude that the adequacy of interventionist causal models depends on stronger metaphysical assumptions than proponents of interventionism typically assume.

Josh Hunt: Norms to Explain By

Accounts of scientific explanation disagree about what’s required for a cause, law, or other ontic structure to be a reason why an event occurs. In short, they disagree about the conditions for explanatory relevance. Nonetheless, these accounts almost universally agree that there is a non-deflationary fact of the matter about explanatory relevance, settled by corresponding truth-makers or worldly states of affairs. By identifying and rejecting this descriptivist assumption, I develop an expressivist account of explanatory relevance—based on Gibbard’s norm-expressivism about rationality. My account rescues metaphysical agnostics from the dilemma of choosing between realism and relativism about explanatory relevance relations. Ethical expressivists have extensively defended their position from relativism, and I adapt these defenses to expressivism about scientific explanation. By respecting ordinary scientific practice, my account rehabilitates an irrealist conception of explanation.

Hans Rott & Eric Raidl:   Difference-making, Relevance, Contraposition: Towards a Logic of Because

The concept of difference-making has been used for the analysis of causes, explanations and reasons. All of these concepts can be expressed in natural language by using the connectives because and since. In this paper we argue that difference-making should also be regarded as applying to (many) conditionals as used in natural language. Very roughly, a difference-making conditional ‘If A, then C’ is true/accepted in a worldly/epistemic state s just in case
(i) C is true/accepted in s revised by the assumption of A, but
(ii) C is not true/accepted in s revised by the assumption of not-A.
We argue that the logic of difference-making conditionals which has been studied by Rott (1986, 2019) and Raidl (2020, 2021, forthcoming) can be extended to get a logic for because by adding the clause that
(iii) A and C are true/accepted in s.

Carolina Sartorio: Difference-Making and Free Will Causalism

Difference-making has been discussed in connection with causation and explanatory relevance, but also in connection with free will and responsibility. The focus of this talk is the role that difference-making plays in “causalist” views of free will and responsibility—views based, precisely, on actual causes or explanations. Of particular interest is the application of those views to indeterministic scenarios, given the special puzzles of indeterministic causation. I discuss this issue in light of the reductionism/primitivism debate about causation.

Jonathan Schaffer: Putting the Making Back into Difference-Making

t is widely thought that causation, grounding, and explanation are connected to difference-making, with difference-making understood via counterfactual patterns. Yet ‘making’ is a causative notion. I argue that the notion of difference-making relevant to causation, grounding, and explanation is not a notion of mere counterfactual patterns but rather a more laden notion involving the making or determination of a difference, where determination is a primitive asymmetric notion (with causation and grounding as species). Specifically I argue that Structural Equation Models (SEMs) embed a primitive notion of determination in (i) the distinction between exogenous (/independent) and endogenous (/dependent) variables, (ii) the use of functions to represent how the value of an exogenous variable is determined by its parents, and (iii) the use of the ‘do’ operation to understand conditionals. Where Woodward says that SEMs are interventionist, I say instead that they are determinationist, requiring no specific causative notion of agency but rather the more general notion of determination.

Michael Strevens: Difference-Making and Mechanism

I will argue (or persuasively assert) that any approach to causal or explanatory relevance that’s built around differencemaking is going to need, in addition to a definition of differencemaking itself, an independent criterion for individuating types of mechanism. I’ll then survey three quite different approaches to individuating mechanism: a metaphysical approach (based on the notion of naturalness), a physical approach (rooted in boundaries of some sort laid down by the fundamental laws of nature), and a pragmatic approach (connecting the individuation of mechanism to certain practical needs). My aim is not so much to tout one of these over the others as to investigate the distinctive appeal of each — though I’ll proceed in a naturalistic vein that has rather more sympathy for the latter two approaches.


Attendance is free but please register in advance by writing to hamburgrelevance (at) gmail (dot) com.


We gratefully acknowledge the financial support provided by the DFG through Stephan Kraemer’s Emmy Noether grant (KR 4516/2-1).