Takayuki KawamotoさんがG＋で紹介してくれた鍵言葉のひとつ

Correlation is not causation：：曲訳すると「'Correlation'なのだよ'causation'とは違うのだよ」

Correlation is not causation

If causes are tendencies that can be counteracted by other tendencies, this should change the way we think of causation, away from Hume’s idea of causation as constant conjunction.

Rather than thinking that robust correlations are indicative of causation, they should be taken as evidence for something other than causation. Identity, classification and essence are typical candidates for robust correlations. All water is H₂O, all whales are mammals and all humans are mortal. Such truths are not subject to interference and the first thing is always correlated with the second. They do not need ceteris paribusqualifying. In contrast, causal truths share none of these features.

Correlation does not imply causation. At best it might be taken as indicative or symptomatic of it. And perfect correlation, if this is understood along the lines of Hume’s constant conjunction, does not indicate causation at all but probably something quite different.

- See more at: http://blog.oup.com/2013/11/correlation-is-not-causation/#sthash.gwkUoe2h.dpuf

Correlation is not causation | OUPblog