Remember that correlation does not imply causation. Just because two things have a correlate with one another, it does not mean that we can jump to an conclusion.
If we look at the graph below, we can see that the rate of diagnosed autism and sales of organic food have an almost perfect correlation. However, we know for a fact that organic food does not cause autism- it just so happens that they correlate with one another.
That is why correlations cannot show cause and effect. To prove that a correlation does so, further studies and experiments must be done.
D. James Joyce's Ulysses is one of the most influential novels of the twentieth century, due largely to the innovations of the literary technique known as stream-of-consciousness.