 A third important temporal asymmetry is the asymmetry of cause and effect. Causes invariably precede their effects in time. Reichenbach attempted to analyze causal direction in terms of macrostatistics or probability. He appealed to his notion of screening-off to define a relation of causal betweenness, and also to define causal direction. It is in this latter context that the RCCP was introduced. The connection between RCCP and causal direction will be discussed in  Section 6  below. Reichenbach also formulated a probabilistic theory of causation, and explored the connections between these new ideas and the mark method for distinguishing causal direction, which he had proposed much earlier (Reichenbach 1958).