Blogs

Essays on QCA, causality, and set-theoretical reasoning.

Causal mechanisms, some second thoughts

Published on roelrutten.com — 5 April 2021

Causality Mechanisms Critical Realism QCA

Causal mechanisms are widely used to explain how causes connect to outcomes across qualitative and quantitative research. This essay problematizes “mechanism talk” and proposes an alternative framing: causal powers.

Main idea: If social reality is heterogeneous and contingent, mechanism-based explanations can be limiting—especially when they assume determinism and leave little room for agency.

Why mechanism talk is attractive

Mechanisms are often presented as the link between independent and dependent variables: a way to move beyond “X affects Y” into “X affects Y because…”. They are also used as a bridge between quantitative findings (population-level effects) and qualitative work (case-level narratives).

Three core problems raised in the essay

Definition ambiguity: a mechanism can mean a sequence/process, or a system of interacting parts—implying different analytic commitments.
Level of abstraction: mechanisms are observed in cases but expected to generalize; equifinality makes this difficult without strong assumptions.
Human agency: mechanism explanations can drift toward passive accounts where agents “trigger” mechanisms but intentionality fades from the causal story.

An alternative: causal powers

The post suggests thinking in terms of causal powers—what entities can do, even if outcomes do not always occur. This helps account for contingency (powers can be exercised or not, and can be effective or ineffective) and keeps human agency in the explanation.

Set theory and the search for extraterrestrial life

Published on roelrutten.com — July 2023

Set theory Complex causality Fermi paradox

Probability arguments about extraterrestrial life can point in opposite directions. This post asks whether set theory offers a clearer intuition: if life requires a highly specific, complex configuration of conditions, then the “set” of life-bearing planets may be extremely small.

Core claim: The more specific and complex the configuration of necessary conditions, the smaller the intersection set becomes— potentially explaining why we do not observe extraterrestrial civilizations.

Starting point: the Fermi paradox

The post contrasts probabilistic reasoning (vast numbers of potentially habitable planets) with the persistent puzzle: if intelligent life is abundant, why don’t we see evidence of it?

A set-theoretical move: list conditions for life

The argument proceeds by enumerating multiple necessary conditions (e.g., key chemical elements plus additional planetary/system features). The post builds a high-dimensional configuration and highlights the resulting combinatorial explosion.

Complex causality implies a sparse set

If each condition is quite specific (covering only a small subset of planets), then their intersection can quickly shrink toward a nearly empty set. The post illustrates this with an analogy: combine a few highly specific attributes and you may uniquely identify a single case out of billions.

Conclusion

While not offering proof, the set-theoretical perspective is presented as a compelling reason to expect that life may be rare, because the configuration required could be extremely unlikely to occur many times.

For the full argumentation and exact assumptions, use the PDF link above.