Halfway proportionality

Abstract

According to the so-called ‘proportionality principle’, causes should be proportional to their effects: they should be both enough and not too much for the occurrence of their effects. This principle is the subject of an ongoing debate. On the one hand, many maintain that it is required to address the problem of causal exclusion and take it to capture a crucial aspect of causation. On the other hand, many object that it renders accounts of causation implausibly restrictive and often reject the principle wholesale. I argue that there is exaggeration on both sides. While one half of the principle is overly demanding, the other half is unobjectionable. And while the unobjectionable half does not block exclusion arguments on its own, it provides a nuanced picture of higher-level causation, fits with recent developments in philosophy of causation, and motivates adjustments to standard difference-making accounts of causation. I conclude that at least half of the proportionality principle is worth taking seriously.

Proportionality in Causation, Part II: Applications and Challenges

“…This ‘disjunction problem’ illustrates a broader issue: in many cases, proportionality appears to recommend causes whose generality does not make them genuinely preferable (Yablo, 1992b, p. 420, Bontly, 2005, p. 340, McDonnell, 2017: §5.1, Vaassen, 2022: §3.2). Consider: …”

“…In particular, does it arise from fundamental physical structure (like that of phase space in classical mechanics), as Strevens (2008, p. 105) suggests? Or is it ‘emergent’ high‐level structure (like that of color space), where this might derive, in part, from high‐level laws involving the properties in question, as Rubenstein (forthcoming) suggests? A powerful reason to adopt the latter view is that high‐level explanations –– like those in psychology and economics –– typically embrace multiply realizable causal processes.…”

“…For one thing, some background conditions are usually required: the presentation of a red target would not yield pecking if the pigeon were blindfolded. As Jäger (2021, p. 583) and Vaassen (2022, p. 2827) point out, this raises a potential problem for proportionality: the conjunction of the ordinary cause with the required background condition threatens to outcompete the ordinary cause. For example, the presentation of the red target fails to screen off the conjunction of the presentation of the red target with the absence of the blindfold.…”

“…In particular, ordinary causes have atypical microphysical realizers. For example, as Vaassen (2022: n.13) observes, some ways of realizing the presentation of a red target involve the ejection of a rogue particle with enough momentum to kill the pigeon 13 . Let a ‘normal’ presentation of a red target be one which does not involve any such rogue particle.…”

“…Blanchard (2020: §4) develops a more concrete interventionist proposal, based on the idea that causal explanations should specify which interventions would prevent the effect. In the absence of a more ‘metaphysical’ ingredient, however, Blanchard's criterion threatens to count many ordinary causes as disjunctive (Rubenstein, forthcoming).…”