 Reichenbach imposes two further axioms—the axioms of order (1949f, p. 137)—that are supposed to hold necessarily of limiting frequencies for infinite time series. One is trivial, essentially asserting that a conditional frequency on lags (Reichenbach’s term for lags is “phases”) of a constant “variable” can always be replaced by a conditional frequency on no lag of that variable. The second, however, appears to be a very strong stationarity principle that is not generally true: the probability of one variable conditional on a specified common lag of other variables is invariant under all uniform translations of the lags. This axiom seems to derive directly from Reichenbach’s interpretation of the foundations of probability, in particular from Reichenbach’s assumption about normal sequences, described below. 