Wright makes one point with absolute clarity: you cannot draw causal conclusions without some causal hypotheses. This echoes what we concluded in Chapter 1: you cannot answer a question on rung two of the Ladder of Causation using only data collected from rung one. Sometimes people ask me, “Doesn’t that make causal reasoning circular? Aren’t you just assuming what you want to prove?” The answer is no. By combining very mild, qualitative, and obvious assumptions (e.g., coat color of the son does not influence that of the parents) with his twenty years of guinea pig data, he obtained a
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