I have always heard, for as long as I remember, that correlation and causality are not the same. That is OK. They are indeed different.
But there is always this implication by many, if not the most, people that correlation is second class and causality is the first class. Causality should be respected while one should be cautious about correlations.
It bothers me whenever I hear that implication about the superiority of causality. To me it is like saying that invention is better than necessity or that a baby is better than his mother. Clearly there is a strong relationship between a mother and a baby and every mother wants her baby to go much farther than her. It is important to remember, however, that baby follows mother. Similarly, if there is no necessity than there is no need for invention, or without an established causal necessity, an invention is worthless.
Correlation is observed in data and then only people think of finding out the causal chain. Except in purely theoretical reasoning, correlation seeds the need for causality. Hence, I say that ‘Correlation is the Mother of Causality’.
In these days of Big Data (hype) if there is some thing really important, it is to understand correlations because then only causality may be explored and established.