1) Do you understand the standard story about the thermodynamic arrow of time? Wikipedia:

Physically speaking, the perception of cause and effect in the dropped cup example is a phenomenon of the thermodynamic arrow of time, a consequence of the Second law of thermodynamics. Controlling the future, or causing something to happen, creates correlations between the doer and the effect, and these can only be created as we move forwards in time, not backwards.

2) Do you understand the standard story about the smoking/tar/cancer example in Pearl's theory of causality? If not, here's a good explanation.

For anything more advanced than that, Ilya is probably your best bet :-)