[crocal]

Just because A occurs before B in « wall clock » time does not mean they are causally related.

[judofyr]

But neither does a logical clock. The implication only goes one way: if A happens before B, then the logical clock of A has to be smaller than that of B. The other way does not have to hold.

[brunoac]

For Lamport Clocks the implication is only one way. But for Vector Clocks it is both ways.