Wikipedia:Reference desk/Archives/Miscellaneous/2017 January 21

= January 21 =

Unknown causal link
This may sound like science and/or mathematics, but I'm not sure that it is really.

Suppose I posit that there is a mutually causal link between two variables X and Y: both affect each other. I make no claim about what the relationship might be, and I do not claim that there are no other factors influencing the two variables, that is, I do not expect a value of X to have an associated value of Y.

So, am I positing anything? Is what I posit entirely without meaning?--Leon (talk) 14:12, 21 January 2017 (UTC)
 * See Causality. You as the proposer are the one to explain whether by "a mutually caused link" you mean a dependence that is predictable, quantifiable, repeatably demostrable in one/both directions, reversible, instantaneous/delayed,... because if you make no such claim, the "caused link" may be no more than a Questionable cause. It's easy to be misled by Post hoc ergo propter hoc e.g. "The rooster crows immediately before sunrise; therefore the rooster causes the sun to rise." and by Superstition. Blooteuth (talk) 15:04, 21 January 2017 (UTC)
 * Okay, I'll say that the link must be, principally, quantifiable, but could be a function of infinitely many other variables. Predictable and repeatedly demonstrable: not sure. Reversible: not sure what you mean. Timing: not necessarily instantaneous.--Leon (talk) 15:13, 21 January 2017 (UTC)
 * Sorry, I disbelieve in functions of "infinitely many variables". See Reversibility disambiguated. Delayed Action at a distance would raise questions of what is being propagated, how fast and through what medium. Blooteuth (talk) 16:06, 21 January 2017 (UTC)


 * What you are positing certainly has meaning. I would express it as
 * $$X=f(Y, Z, W)$$
 * $$Y=g(X, Z, V)$$


 * You have bidirectional causality, jointly confounding factors Z, and individual confounding factors W and V. Loraof (talk) 17:34, 21 January 2017 (UTC) Actually W and V are not called confounding factors, just additional causes. Loraof (talk) 19:19, 21 January 2017 (UTC)


 * Our article causality claims that causes must precede effects, implying that there could be no such thing as bidirectional causality. But usage depends on the discipline; for example, in economics it is common to allow instantaneous causality, as when the current quantity of a good demanded depends on the current price. Loraof (talk) 19:54, 21 January 2017 (UTC)
 * It would only allow for no simultaneous bidirectional causality. It is trivial to see bidirectional causality exists in the real world; feedback loops. Fgf10 (talk) 21:36, 21 January 2017 (UTC)