Ex_1: Cannabis induziert Schizophrenie? Fakten: 1. Cannabis Konsum korreliert mit doppeltem Risiko im späteren Leben mit Schikzophrenie diagnostiziert zu werden 2. Cannabis Konsum korreliert mit frühem Ausbruch von Symptomen
Ex_1: Cannabis induziert Schizophrenie? 1. Studie Menschen die mit Cannabis induzierter psychotischer Episode (E) diagnostiziert werden entwickeln später oft Schizophrenie (S). Variablen: Cannabis Konsum (C), E, S
Ex_1: Cannabis induziert Schizophrenie? 2. Studie Menschen mit E e und genetischer Disposition (G) g, haben ein Schizophrenie Risiko entsprechend dem anderer Menschen mit G g. Variablen: C, E, S, G
Ex_1: Cannabis induziert Schizophrenie? Studie 1 Studie 2
Hume Regularity Hume Regularity Lewis Counterfactual Salmon Process ? [Pearl, Spirtes and Scheines] Probability Some theories of causation, and their most prominent proponents
Hume's categories, from perception to the idea of causation
David Lewis Counterfactual Dependence account A causes B means: CF: B counterfactually depends on A Not A then necessarily not B A then necessarily B When is this the case? If worlds w1 were CF holds are closer to the actual world than worlds w2, where CF does not hold (i.e. A but not B).
Selected traditional Problems for theories of causation Preemption Overdetermination Spurious correlation Omission
Woodwards Theorie der Kausalität A causes B iff we can use their relationship to manipulate (control) the value of B. Direct cause [DC] Total Cause [TC] Contributing Cause [CC]
Woodward – Central Issues 2 Modes of Representation: Directed Graphs Equations 2 Fundamental Concepts Intervention Invariance
Woodward – More Detail Interventions: - possibility - ambiguity - precision (top-down manipulation) Generalization: - what-if-things-had-been-different? questions - robustness & stability, scope & range
Woodward – More Detail 2 Status of the causal claim: - C verursacht E in Hinsicht auf V!