Rationality Quotes February 2013

arundelo

Another monthly installment of the rationality quotes thread. The usual rules apply:

Please post all quotes separately, so that they can be upvoted or downvoted separately. (If they are strongly related, reply to your own comments. If strongly ordered, then go ahead and post them together.)
Do not quote yourself.
Do not quote comments or posts from Less Wrong itself or from Overcoming Bias.
No more than 5 quotes per person per monthly thread, please.

Another monthly installment of the rationality quotes thread. The usual rules apply:

Please post all quotes separately, so that they can be upvoted or downvoted separately. (If they are strongly related, reply to your own comments. If strongly ordered, then go ahead and post them together.)
Do not quote yourself.
Do not quote comments or posts from Less Wrong itself or from Overcoming Bias.
No more than 5 quotes per person per monthly thread, please.

You originally were talking about a duck in your closet, which isn't the same as thing as being around ducks.

The discussion reminds me of this, which makes the point that, while corelation is not causation, if there's no corelation, there almost certainly isn't causation.

Yes, this is completely wrong. There is frequently no correlation but strong causation due to effect cancellation (homeostasis, etc.)

Here's a recent paper making this point in the context of mediation analysis in social science (I could post many more):

http://www.quantpsy.org/pubs/rucker_preacher_tormala_petty_2011.pdf

Nancy, I don't mean to jump on you specifically here, but this does seem to me to be a special instance of a general online forum disease, where people {prefer to use | view as authoritative} online sources of information (blogs, wikipedia, ... (read more)

21Richard_Kennaway13y

This is completely wrong, though not many people seem to understand that yet. For example, the voltage across a capacitor is uncorrelated with the current through it; and another poster has pointed out the example of the thermostat, a topic I've also written about on occasion. It's a fundamental principle of causal inference that you cannot get causal conclusions from wholly acausal premises and data. (See Judea Pearl, passim.) This applies just as much to negative conclusions as positive. Absence of correlation cannot on its own be taken as evidence of absence of causation.

9simplicio13y

Not disagreeing, but just wanted to mention the useful lesson that there are some cases of causation without correlation. For example, the fuel burned by a furnace is uncorrelated with the temperature inside a home. (See: Milton Friedman's thermostat.)