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Causality. What is a cause?. On September 11, 2001, the World Trade Center Towers collapsed. What caused them to fall? Heath Ledger died in January of 2008. What caused his death?. Hume. Relations of ideas Ideas are truths that are independent of human reasoning
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What is a cause? • On September 11, 2001, the World Trade Center Towers collapsed. What caused them to fall? • Heath Ledger died in January of 2008. What caused his death?
Hume • Relations of ideas • Ideas are truths that are independent of human reasoning • Triangles have 3 sides whether or not there are people to think about them • Matters of fact • Facts must be perceived or created by humans • Causes are matters of fact, not ideas
What leads to causal inferences? • Physical proximity • Temporal proximity • Channel for action • Similar causes lead to similar effects • Generalization from past instances • The DP rule • DP=p(E|C) - p(E|¬C) • A cause must change the probability that some event occurs
Simple launching events • The standard event is seen as causal • If the balls do not touch, then it is not seen as causal • If the balls come together and stop and then the second one moves, it is not seen as causal
Causes and counterfactuals • Counterfactual statements • Statements that presume some event had not occurred. • If I hadn’t eaten so much, I wouldn’t feel sick now. • Counterfactual reasoning is related to causality • People must be able to reason about what would have occurred had the putative cause not happened.
Causes and explanations • Causes presume some type of explanation • The type of explanation desired sets the context for the cause • Many different things may be seen as causal depending on the type of explanation required • Levels of explanation in Psychology (Marr) • Computational-level explanations • Algorithmic-level explanations • Implementational-level explanations