Mitchell_Porter comments on The Fabric of Real Things - Less Wrong

16 Post author: Eliezer_Yudkowsky 12 October 2012 02:11AM

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Comment author: lukeprog 12 October 2012 06:43:23AM 4 points [-]

Once again speaking as the author of Eliezer's Sequences and Mainstream Academia...

Like Eliezer, I haven't seen anyone suggesting that a universe is a connected fabric of causes and effects in the Pearlian sense. Nor have I seen anyone suggest that one can only meaningfully talk about things that one can find by tracing causal links.

If some young philosopher wants to publish some great, attention-grabbing papers in Nous early in their career, I suggest they write up the philosophy-paper versions of the core ideas in The Useful Idea of Truth and The Fabric of Real Things (citing Eliezer, of course).

Comment author: Mitchell_Porter 12 October 2012 07:02:41AM 7 points [-]

What would it even mean to say that the universe is a fabric of cause and effect "in the Pearlian sense of causality"? Pearl originated a new method of causal analysis, not a new concept of causation.

Comment author: Pfft 13 October 2012 02:48:04AM 1 point [-]

I guess it means causation as manipulability, as opposed to e.g. causation as contrafactual?

Comment author: Eugine_Nier 13 October 2012 04:19:35AM 1 point [-]

How is causation as manipulability "Pearlian"? Pearl's whole point is that it's possible to determine causality without manipulating.

Comment author: pragmatist 19 October 2012 01:24:02AM *  2 points [-]

In so far as Pearl has a theory of causation, it is a manipulability theory. Sure, Pearl provides a method for drawing causal conclusions from data about correlations. But what he means by causation is cashed out in terms of how interventions on one variable affect another variable, not just in terms of correlations. Correlations are indicators of causation for Pearl, but they don't constitute causation. The structural equations Pearl uses to represent causal relationships are meant to capture not just de facto mathematical relations between variables, they support counterfactuals. They tell us what would happen to the variable on the left hand side of the equation if the variables on the right hand side were manipulated.

See section 6 of the SEP article for connections between the manipulability theory of causation and Pearl's formalism.

Comment author: Pfft 13 October 2012 05:09:55PM 0 points [-]

But first you need to know what causality is. While the general idea that "causality is about manipulations" was around before Pearl, he certainly popularized it, and his causal bayesian networks and the do-calculus made it something that could be studied mathematically.