How correlation differs from causeation?

Correlation means that when one quantity increases, the other tends to increase as well. Causation means that the increase in one quantity CAUSES an increase in another quantity. It is a common error to assume that correlation implies causation; sometimes correlation is caused by causation, but not always. For example: let's say that the price of sugar gradually went up over the last 10 years; so did the price of cooking oil. Neither one is caused by the increase of the other; rather, they are both part of a larger tendency, namely, inflation. As another example, during the same 10-year period, the population of your country gradually increased. This is independent of the inflation; both prices and population simply tend to increase over time.